[Federal Register Volume 71, Number 81 (Thursday, April 27, 2006)]
[Rules and Regulations]
[Pages 24972-25008]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-3165]



[[Page 24971]]

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Part III





Department of Energy





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Office of Energy Efficiency and Renewable Energy



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10 CFR Part 431



Energy Conservation Program: Test Procedures for Distribution 
Transformers; Final Rule

  Federal Register / Vol. 71, No. 81 / Thursday, April 27, 2006 / Rules 
and Regulations  

[[Page 24972]]


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DEPARTMENT OF ENERGY

Office of Energy Efficiency and Renewable Energy

10 CFR Part 431

[Docket No. EE-TP-98-550]
RIN 1904-AA85


Energy Conservation Program: Test Procedures for Distribution 
Transformers

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Final rule.

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SUMMARY: Pursuant to Sections 323(b)(10) and 346(a) of the Energy 
Policy and Conservation Act, as amended, (EPCA or the Act), 42 U.S.C. 
6293(b)(10) and 6317(a), the Department of Energy (DOE or the 
Department) promulgates a rule prescribing test procedures for 
measuring the energy efficiency of distribution transformers under 
EPCA, definitions to delineate the products covered by the test 
procedures, provisions (including a sampling plan) manufacturers must 
use to implement the test procedures, provisions to allow manufacturers 
to use calculation methods to determine the efficiency of some of their 
models, and enforcement testing for distribution transformers. The 
Department will use the new test procedures in evaluating what energy 
conservation standards are warranted for distribution transformers 
other than the low-voltage dry-type. When DOE promulgates such 
standards, then the test procedures and other provisions adopted today 
will be used to determine the efficiencies and assess compliance of the 
transformers subject to these standards. For low-voltage dry-type 
distribution transformers, the new standards prescribed for them in 
section 325(y) of EPCA, 42 U.S.C. 6295(y), go into effect on January 1, 
2007, and all of the provisions of today's rule will become applicable 
to those transformers at that time.

EFFECTIVE DATE: This final rule is effective May 30, 2006, except for 
Sec.  431.197(a)(4)(i), section 6.2(f) of Appendix A and section 6.2(b) 
and (c) of Appendix A which contain information collection requirements 
that have not been approved by the Office of Management and Budget 
(OMB). The Office of Energy Efficiency and Renewable Energy will 
publish a document in the Federal Register announcing the effective 
date.

FOR FURTHER INFORMATION CONTACT: Cyrus Nasseri, Project Manager, Test 
Procedures for Distribution Transformers, Docket No. EE-TP-98-550, 
United States (U.S.) Department of Energy, Energy Efficiency and 
Renewable Energy, Building Technologies Program, EE-2J, 1000 
Independence Avenue, SW., Washington, DC 20585-0121, (202) 586-9138, 
email: [email protected].
    Francine Pinto, Esq., U.S. Department of Energy, Office of General 
Counsel, GC-72, 1000 Independence Avenue, SW., Washington, DC 20585-
0121, (202) 586-9507, email: [email protected].

SUPPLEMENTARY INFORMATION:

I. Introduction
    A. Authority and Background
    B. Summary of the Final Rule
II. Discussion
    A. General
    B. Transformers Subject to the Test Procedure--Definition of 
Distribution Transformer
    1. General
    2. Incorporation and Definition of EPCA's Exclusions--General
    3. Specific EPCA Exclusions
    a. Transformers with Tap Ranges of 20 Percent or More and 
Special Impedance Transformers
    b. Testing Transformers
    c. Grounding Transformers
    4. Other Exclusions Considered
    5. Rebuilt or Refurbished Distribution Transformers
    6. Coverage of Liquid-Filled Transformers
    C. Test Procedure for Distribution Transformers
    1. General Discussion
    2. Specific Provisions of the Test Procedure
    a. Testing Harmonic Transformers
    b. Determining Winding Temperatures
    c. Test Set Neutrals
    d. Losses from Auxiliary Devices
    e. Testing of Multiple Voltage Transformers
    f. Short-Circuiting Conductor Strap
    g. Revisions Suggested by NEMA in TP 2-2005
    h. Language Corrections as to Conversion of the Resistance 
Measurement to the Reference Temperature and Conducting the No-Load 
Loss Test
    D. Basic Model
    1. General Discussion
    2. Definition of a Basic Model
    E. Manufacturer's Determination of Efficiency
    1. General Discussion
    2. Sampling Plan
    3. Alternative Efficiency Determination Method (AEDM)
    F. Enforcement Procedures
III. Procedural Requirements
    A. Review Under Executive Order 12866
    B. Review Under the Regulatory Flexibility Act of 1980
    C. Review Under the Paperwork Reduction Act
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act of 1999
    I. Review Under Executive Order 12630
    J. Review Under the Treasury and General Government 
Appropriations Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Congressional Notification
IV. Approval of the Office of the Secretary

I. Introduction

A. Authority and Background

    Part C of Title III of the Energy Policy and Conservation Act 
(EPCA) provides for an energy conservation program for certain 
industrial equipment. (42 U.S.C. 6311-6317) Section 346 of EPCA states 
that the Secretary of Energy (Secretary) must prescribe testing 
requirements and energy conservation standards for those ``distribution 
transformers'' for which the Secretary determines that standards 
``would be technologically feasible and economically justified, and 
would result in significant energy savings.'' (42 U.S.C. 6317(a)) The 
recent amendments to EPCA set forth in the Energy Policy Act of 2005 
(EPACT 2005), Pub. L. 109-58, accomplish the following for this 
equipment: (1) Section 321(35) of EPCA now defines ``distribution 
transformer'' (42 U.S.C. 6291(35)), (2) Section 323(b)(10) of EPCA 
provides that the testing requirements ``shall be based on the 
`Standard Test Method for Measuring the Energy Consumption of 
Distribution Transformers' prescribed by the National Electrical 
Manufacturers Association (NEMA TP 2-1998).'' (42 U.S.C. 
6293(b)(10)),\1\ and (3) section 325(y) of EPCA prescribes minimum 
efficiency levels for low-voltage dry-type distribution transformers 
(42 U.S.C. 6295(y)).
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    \1\ Section 323(b)(10)(B) also provides that the Department may 
``review and revise'' the test procedures established under that 
subparagraph. (42 U.S.C. 6293(b)(10)(B))
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    On October 22, 1997, the Department issued a notice setting forth 
its determination (hereafter referred to as the ``Determination'') 
that, based on the best information it had available, energy 
conservation standards for electric distribution transformers appeared 
to be technologically feasible and economically justified, and were 
likely to result in significant energy savings. 62 FR 54809.
    The Department subsequently began the process for its issuance of 
test procedures for distribution transformers. On February 10, 1998, 
the Department held a public workshop (the ``1998 workshop'') to 
discuss the following issues: (a) Whether DOE

[[Page 24973]]

should adopt national and international consensus standards as its test 
procedures for determining the energy efficiency of distribution 
transformers, (b) defining the transformers that the test procedures 
will cover, (c) whether, and to what extent, there is a burden on 
industry, especially on manufacturers, because of additional testing 
and data processing, (d) the definition of ``basic model'' for 
distribution transformers, (e) the sampling plan for units to be 
tested, (f) the selection of an energy consumption measure for 
distribution transformers, (g) the selection of reference temperatures, 
(h) the requirements for applying corrections to measurement data, and 
(i) the requirements for quality assurance in testing. The Department 
also gave interested parties an opportunity to submit written comments 
on these issues.
    In 1998, the National Electrical Manufacturers Association (NEMA) 
published ``NEMA Standards Publication No. TP 2-1998, Standard Test 
Method for Measuring the Energy Consumption of Distribution 
Transformers,'' (NEMA TP 2-1998) a publication that extracts and 
presents pertinent parts of the current industry standards for 
distribution transformer efficiency testing. NEMA TP 2-1998 also 
presents a weighted average method to compute the energy efficiency of 
transformers, in order to demonstrate compliance with the efficiency 
levels in NEMA Standard TP 1-1996 (NEMA TP 1).\2\ Comments received at 
the 1998 workshop, written comments associated with this workshop, and 
NEMA TP 2-1998 formed the basis for preparing the November 12, 1998, 
Notice of Proposed Rulemaking (the ``1998 proposed rule'') in this 
proceeding. 63 FR 63359.
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    \2\ NEMA TP 1 contains suggested efficiency levels. Its full 
name and title are ``NEMA Standards Publication No. TP 1-1996, Guide 
for Determining Energy Efficiency for Distribution Transformers.'' 
NEMA TP 1 was updated in 2002, with modifications to some of the 
efficiency levels.
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    In the 1998 proposed rule, the Department proposed to adopt testing 
methods that (1) it could use to evaluate distribution transformers 
during the development of efficiency standards, and (2) manufacturers 
and DOE would use to determine the efficiency of the transformers which 
the standards would cover. DOE proposed to incorporate by reference as 
its test methods the provisions from either the Institute of Electrical 
and Electronics Engineers (IEEE) Standards C57.12.90-1993 and 
C57.12.91-1993 (using IEEE C57.12.00-1993 as an additional reference 
source), or NEMA TP 2-1998. The 1998 proposed rule also included 
proposed definitions of ``distribution transformer'' and related terms, 
of terms used in the test procedure provisions, and of ``basic model.'' 
It also proposed a sampling plan for applying the test procedures to 
perform compliance testing. The sampling approach was based on the plan 
for compliance testing in 10 Code of Federal Regulations (CFR) Part 
430, which contains energy efficiency requirements for consumer 
products, but tailored to distribution transformers and with a minimum 
sample size of five units. The Department selected this approach 
because it appeared to provide a satisfactory balance between assuring 
the accuracy of efficiency ratings for distribution transformers and 
minimizing the testing burden on manufacturers. The Department also 
sought comment on three alternative compliance approaches for basic 
models produced in small numbers.
    DOE held a public meeting on January 6, 1999, on the 1998 proposed 
rule and received nine written comments. After reviewing the oral and 
written comments, DOE concluded that the comments raised a number of 
significant issues that required additional analysis. On June 23, 1999, 
the Department reopened the comment period on the 1998 proposed rule, 
64 FR 33431, (the ``1999 reopening notice'') to provide an opportunity 
for additional public comment on the following issues: (a) The 
suitability of NEMA TP 2-1998 for adoption as the DOE test procedure; 
(b) the adequacy of stakeholder opportunity to review NEMA TP 2-1998; 
(c) the transformers covered under the definition of ``distribution 
transformer;'' (d) the suitability of the definition of ``basic model'' 
for the purpose of grouping transformers to limit the test burden; and 
(e) the appropriateness of the proposed sampling plan and a number of 
alternatives for demonstrating compliance. The Department received five 
comments in response to the 1999 reopening notice.
    On the basis of these comments, two additional comments it received 
subsequently, and its review of the issues raised by the 1998 proposed 
rule and the 1999 reopening notice, the Department issued a 
supplemental notice of proposed rulemaking (SNOPR). 69 FR 45506 (July 
29, 2004). In the SNOPR, DOE proposed to adopt (1) a new ``stand 
alone'' test procedure for distribution transformers, drafted by the 
Department and consisting almost entirely of test methods contained in 
NEMA TP 2-1998 and other existing industry standards, (2) revised 
definitions to establish which transformers the test procedure covers, 
(3) a new definition of ``basic model'' and a new sampling plan, to 
implement the test procedures, (4) provisions to allow manufacturers to 
use calculation methods, instead of testing, to determine the 
efficiency of some of their models, and (5) enforcement procedures, 
including a testing protocol, for distribution transformers. DOE held a 
public meeting on September 27, 2004, on the SNOPR (the ``2004 public 
meeting'') and received six written comments.
    Concurrently with this rulemaking, the Department has evaluated the 
establishment of energy conservation standards for distribution 
transformers. On October 2, 2000, the Department made available a 
Framework Document for Distribution Transformer Energy Conservation 
Standards Rulemaking, which was the subject of a public workshop on 
November 1, 2000, and on which stakeholders submitted written comments 
before and after the workshop. 65 FR 59761 (October 6, 2000). 
Thereafter, the Department visited manufacturers of distribution 
transformers and posted on DOE's website \3\ several draft reports 
concerning the development of standards for these transformers. On the 
same day that it published the SNOPR, DOE issued an Advance Notice of 
Proposed Rulemaking (ANOPR) for distribution transformer standards. 69 
FR 45376 (July 29, 2004). Several of the written comments DOE received 
in response to the ANOPR address issues raised in the SNOPR, and the 
Department has referenced them in the docket of this rulemaking and has 
considered them in formulating today's final rule.
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    \3\ http://www.eere.energy.gov/buildings/appliance_standards/commercial/dist_transformers.html
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    On October 18, 2005, the Department published a final rule to place 
in its regulations the energy conservation standards, and related 
definitions, that Congress prescribed in EPACT 2005 for certain 
consumer products and commercial and industrial equipment. 70 FR 60407. 
The rule included the definitions for ``distribution transformer'' and 
``low-voltage dry-type distribution transformer,'' and the standards 
for low-voltage dry-type distribution transformers, that were contained 
in EPACT 2005. 10 CFR sections 431.192 and 431.196. The Department put 
the provisions for all of the commercial and industrial products 
covered by EPACT 2005, including those for distribution transformers, 
in 10 CFR Part 431. 70 FR 60414-18. In the prior Federal Register 
notices dealing

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with test procedures for distribution transformers, DOE had proposed 
adding a new part 432 to include requirements for distribution 
transformers. 63 FR 63376, 63369; 69 FR 45517, 45520. As a result of 
DOE's decision, in response to EPACT 2005, to incorporate provisions 
for distribution transformers into 10 CFR Part 431, today's final rule 
places the new test procedures for this equipment in Subpart K to 10 
CFR Part 431.

B. Summary of the Final Rule

    The test procedure in today's rule is based on the test methods 
contained in NEMA TP 2-1998 \4\ and IEEE Standards C57.12.90-1999 and 
C57.12.91-2001. Initially, the Department will use the test procedure 
to evaluate distribution transformers for which it is currently 
developing energy conservation standards. When DOE promulgates such 
standards, the Department will then require manufacturers to use the 
test procedure to determine compliance with the standards and as a 
basis for their efficiency representations for covered transformers. 
The Department would also use the test procedure in any enforcement 
proceeding concerning compliance with such standards and related 
labeling requirements. In addition, the test procedures will become 
mandatory for all of these purposes--compliance determination, 
representations and enforcement--for low-voltage dry-type distribution 
transformers when standards go into effect for them, pursuant to 42 
U.S.C. 6295(y), on January 1, 2007.
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    \4\ In September 2005, NEMA provided the Department with its 
revised test procedure document, TP 2-2005, which is similar to the 
rule language in the SNOPR. The Department has treated this 
submission as a comment on the SNOPR, has incorporated into today's 
rule a number of the changes that this revision made to the SNOPR's 
rule language, and addressed below the significant differences 
between the revision and the SNOPR.
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    The language of today's rule sets forth all testing requirements, 
without reference to other sources, for determining the energy 
efficiency of distribution transformers. Measurement of electric power 
consumed by the transformer is in the form of no-load and load losses. 
The rule specifies methods with which to measure the temperature, 
current, voltage, extent of distortion in voltage waveform, and direct 
current resistance of the windings. The rule also prescribes provisions 
for calculating efficiency. The testing methods are largely the same as 
those proposed in the SNOPR, with several clarifying changes and a few 
changes to provide manufacturers with greater flexibility.
    Today's rule amends the definition of ``distribution transformer'' 
that DOE recently adopted, 70 FR 60416, by adding capacity limits (the 
same ones the Department proposed in the SNOPR), making minor language 
and format changes, and clarifying the exclusion of transformers with 
tap ranges greater than 20 percent. As discussed below, today's 
definition conforms to, and incorporates the relevant language from, 
the definition that EPACT 2005 added to EPCA. (42 U.S.C. 6291(35)) The 
Department's definition establishes which transformers the test 
procedure covers. It uses the approach DOE proposed in the SNOPR--a 
broad definition with numerical criteria, but narrowed by the exclusion 
of specific types of transformers, many of which are not commonly 
understood to be distribution transformers. The numerical criteria 
(except for the added capacity limits) and the exclusions are the same 
as those in EPCA's new definition. They include virtually the same 
primary and secondary voltage ranges the Department proposed in the 
SNOPR, most of the exclusions DOE proposed, and no additional 
exclusions. Today's definition of distribution transformer, however, 
does not include the exclusions of K-factor and harmonic mitigating 
distribution transformers, which DOE proposed in the SNOPR but which 
are absent from the EPCA definition. Stakeholders will have the 
opportunity in the energy conservation standards rulemaking to comment 
to the Department on whether standards should apply to these 
transformers.
    Today's rule contains several features designed to reduce the 
number of transformers that manufacturers would have to test. First, 
the Department allows manufacturers to group models into ``basic 
models'' for testing purposes, and defines ``basic model'' as proposed 
in the SNOPR, with minor clarifications. Second, the rule includes the 
same type of compliance sampling plan proposed in the SNOPR, except 
that the sampling plan tolerance is based on a single-unit sample 
tolerance (confidence limit) of eight percent, rather than the five 
percent DOE proposed. And third, today's rule allows manufacturers to 
use alternative methods, other than testing, to determine the 
efficiency of some basic models. The rule incorporates the SNOPR 
proposal except that manufacturers need not use a different method for 
each of the following groups of distribution transformers: low-voltage 
dry-type, medium-voltage dry-type, and liquid-immersed. Manufacturers 
can use a single method for transformers in two or all three of these 
groups so long as the method is validated separately in each of the 
groups for which the manufacturer uses it. Today's rule also contains 
the enforcement procedures proposed in the SNOPR, including a testing 
protocol, modified to be consistent with the revised compliance 
sampling plan tolerance. Finally, the Department is republishing in 
this rule, without substantive change, the standards for low-voltage 
dry-type distribution transformers that it originally codified at 70 FR 
70417. Today's rule contains a revised table that has a clearer, more 
appropriate format than the table in the original rule. The table also 
includes the reference conditions for the standards, which DOE 
inadvertently omitted from the initial codification but which are 
essential elements of the standards, as set forth in Table 4-2 of NEMA 
TP 1-2002, from which EPCA incorporates the standards. (42 U.S.C. 
6295(y))

II. Discussion

A. General

    Representatives of several organizations attended the public 
meeting on September 27, 2004, including trade associations (Copper 
Development Association, National Electrical Manufacturers Association 
(NEMA), and National Rural Electric Cooperative Association), 
transformer manufacturers (Acme Electric Corporation (ACME), ERMCO 
Distribution Transformers (ERMCO), Federal Pacific Transformer (Federal 
Pacific or FPT), Kuhlman Electric Corporation, Pemco Corporation 
(Pemco), and Howard Industries, Inc. (Howard Industries or Howard)), a 
core steel manufacturer (AK Steel Corporation), electric utility 
companies (Georgia Power Company and Ameren Services), the Canadian 
Government (Natural Resources Canada), the National Institute of 
Standards and Technology (NIST) of the U.S. Department of Commerce, and 
private research/consulting entities (BB&F Associates, Lawrence 
Berkeley National Laboratory, Merritt and Associates, Navigant 
Consulting, Inc., and Optimized Program Services, Inc.). NEMA also 
submitted a written statement in advance of the public meeting. 
Following the public meeting, ERMCO, Federal Pacific, Howard 
Industries, Cooper Power Systems (Cooper) and NEMA each submitted a 
written statement. In addition, the Department received ten comments in 
its energy conservation standards rulemaking that pertained to both the

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test procedure and the energy conservation standards rulemakings. 
Therefore, the Department cross-referenced these comments from the 
energy conservation standards docket (EE-RM/STD-00-550) to this 
proceeding. The ten cross-referenced comments were submitted by Pemco, 
ERMCO, Harmonics Limited, NEMA, Federal Pacific, HVOLT, Inc. (HVOLT), 
Oregon Department of Energy (ODOE), Howard Industries, Power Quality 
International (PQI) and EMS International Consulting (EMS).
    The following summarizes the issues addressed in the preamble of 
the SNOPR and discusses in detail the points on which significant 
comments were presented during and after the public meeting.

B. Transformers Subject to the Test Procedure--Definition of 
Distribution Transformer

1. General
    Although EPCA directed DOE to prescribe energy conservation 
standards and test procedures for certain ``distribution transformers'' 
(42 U.S.C. 6317(a)), until recently the Act did not define that term. 
Therefore, the Department undertook to adopt such a definition in this 
rulemaking. It proposed a definition in the 1998 proposed rule, 63 FR 
63362-63, 63369-70, addressed the issue again in the 1999 reopening 
notice, 64 FR 33432-34, and proposed a substantially revised definition 
in the SNOPR. 69 FR 45506. That revised definition included 
transformers meeting numerical criteria as to primary and secondary 
voltage and capacity, and excluded specifically listed types of 
transformers. 69 FR 45509-10, 45520-22. The Department designed that 
definition primarily to (1) encompass within ``distribution 
transformer'' only those transformers commonly understood to be 
distribution transformers, i.e. those made for the distribution of 
electricity, and (2) exclude those distribution transformers for which 
standards clearly would not produce significant energy savings. 69 FR 
45509-10.
    EPACT 2005 recently revised EPCA to include a definition of 
``distribution transformer'' (42 U.S.C. 6291(35)), thus filling the gap 
DOE had sought to fill with its own definition. As part of the final 
rule mentioned above, to place in the CFR certain provisions prescribed 
in EPACT 2005, the Department incorporated this new definition, almost 
verbatim, into 10 CFR section 431.192. 70 FR 60407, 60416-17. (In the 
paragraphs that follow, the new definition is referred to as the 
``EPCA'' or ``new'' definition.) The EPCA definition is similar in 
approach and content to the definition proposed in the SNOPR. It 
includes numerical criteria--a maximum input voltage and frequency that 
are similar to those in the SNOPR definition, and a maximum output 
voltage that is identical--as well as a list of excluded transformers 
that is quite similar to the SNOPR's list of excluded transformers. 
(The differences between EPCA's list of exclusions and the SNOPR's list 
are discussed below. Today's rule adheres to the EPCA list.) The new 
definition also authorizes DOE to add to the list of exclusions any 
type of transformer that meets certain criteria.
    One significant difference exists, however, between the numerical 
criteria in the EPCA and SNOPR definitions. No capacity ranges are 
stated in the new definition, whereas the SNOPR definition limits the 
term ``distribution transformer'' to liquid immersed units with a 
capacity of 10 kVA to 2500 kVA, and dry-type units with a capacity of 
15 kVA to 2500 kVA. (The Department has been using a similar definition 
to delineate the transformers it is evaluating in the standards 
rulemaking. 69 FR 45381-45384.) Transformers outside of these ranges 
are not typically used for electricity distribution, which is the 
commonly understood function of a distribution transformer. The 
Department received no adverse comment on these proposed ranges. 
Moreover, NEMA agreed with the proposed lower capacity limit for dry-
type transformers, indicating that efficiency standards for 
transformers with lower kVA ratings would fail to meet the criteria in 
section 346 of EPCA. (NEMA, No. 39 at p. 2; Public Meeting Transcript, 
No. 42.11 at p. 22) \5\ But notwithstanding the lack of any explicit 
capacity limits in the EPCA definition of distribution transformer, as 
a practical matter an upper capacity limit is implicit in that 
definition. A transformer's capacity is to some extent tied to its 
primary (input) and secondary (output) voltages. Therefore, the maximum 
limits for primary and secondary voltages, of 34.5 kilovolts and 600 
volts, respectively, in the EPCA definition have the practical effect 
of limiting transformers that meet the definition to those with a 
maximum capacity in the range of approximately 3750 to 5000 kVA, or 
possibly slightly higher. The voltage limits in the EPCA definition, 
however, subsume no lower limit on capacity.
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    \5\ A notation in the form ``NEMA, No. 39 at p. 2'' identifies a 
written comment the Department has received and has included in the 
docket of this rulemaking. This particular notation refers to a 
comment (1) by the National Electrical Manufacturers Association 
(NEMA), (2) in document number 39 in the docket of this rulemaking 
(maintained in the Resource Room of the Building Technologies 
Program), and (3) appearing on page 2 of document number 39. 
Likewise, ``Public Meeting Transcript, No. 42.11 at p. 22,'' for 
example, would refer to page 22 of the transcript of the ``Public 
Meeting on Test Procedures for Distribution Transformers'' held in 
Washington, DC, September 27, 2005, which is document number 42.11 
in the docket of this rulemaking.
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    It is unclear whether ``distribution transformer'' as now defined 
in EPCA and DOE's regulations is, or can be, subject to capacity ranges 
other than the just-mentioned upper limit. On the one hand, the new 
definition includes no such capacity limitation, and it authorizes DOE 
to exclude from the definition, by rule, any transformer if it is 
designed for a special application, is unlikely to be used in a general 
purpose application, and significant energy savings would not result 
from applying standards to it. (42 U.S.C. 6291(35)(B)(iii)) This 
suggests that unless, and until, DOE acts and identifies capacity 
ranges that meet these criteria, they are not part of the new 
definition of distribution transformer. On the other hand, it is 
uncertain whether Congress intended to regulate as distribution 
transformers units outside of the capacity ranges in the SNOPR, because 
few are used to distribute electricity. In addition, at the same time 
it enacted the new distribution transformer definition, Congress also 
directed use of, and incorporated into EPCA, provisions of NEMA TP 2-
1998 and NEMA TP 1-2002, respectively (42 U.S.C. 6293(b)(10) and 
6295(y)), both of which apply only to transformers with capacity ranges 
similar to those in the SNOPR definition. Thus, Congress may have 
intended to limit the term ``distribution transformer'' to transformers 
within the capacity ranges that normally characterize transformers that 
distribute electricity. If so, that would mean the Department's 
authority to regulate the efficiency of transformers under 42 U.S.C. 
6317 would be limited to transformers within these capacity ranges.
    Given the inclusive language of EPCA's definition of distribution 
transformer, however, the Department is not prepared at this point to 
infer that EPCA imposes this limitation. The Department also does not 
possess information on whether transformers outside of these ranges 
would meet the criteria in 42 U.S.C. 6291(35)(B)(iii), particularly the 
one on energy savings from applying standards, for exclusion from the 
definition of distribution transformer. The standards rulemaking

[[Page 24976]]

for distribution transformers, in which DOE would develop such 
information, and this test procedure rulemaking to a slightly lesser 
extent, have focused almost entirely on transformers within the 
capacity ranges. Thus, at the present time, DOE is proceeding on the 
premise that ``distribution transformer'' as defined in EPCA includes 
transformers outside the capacity ranges in the SNOPR.
    One option, therefore, would be for the Department to retain this 
definition in its rules, not revise it in today's rule, and apply it in 
any standards rulemaking as well. That would have little or no impact 
on adoption of the test procedures in today's rule, but it might delay 
issuance of the rule. The Department believes that the test procedures 
as proposed in the SNOPR and revised for inclusion in today's rule 
would be valid for determining the efficiency of transformers with 
capacities up to the limits implicit in EPCA's definition, and below 
the lower end of the proposed ranges proposed in the SNOPR. 
Nevertheless, because DOE had not proposed to apply the test procedure 
to transformers with such capacities, it would have to provide some 
opportunity for public comment on the applicability of the test 
procedure to those transformers. Doing so could delay completion of 
this rulemaking.
    The impact in the standards rulemaking, of applying the EPCA 
definition without capacity limits, would be much greater than the 
impact of doing so in this test procedure rulemaking. Formulating 
standards for a product involves developing an understanding of, and 
evaluating, factors such as the nature of the product, its market, the 
technical feasibility of potential efficiency improvements, the 
manufacturing costs of such improvements, the resulting energy savings, 
the cost of the improved product(s) to purchasers, the impact of 
efficiency standards on manufacturers and utilities, and environmental 
and employment impacts, as well as other factors unique to a particular 
product. The Department has been engaged in such activities with 
respect to distribution transformers for over five years, examining for 
the most part products within the capacity ranges in the SNOPR 
definition of distribution transformer. It is now developing proposed 
standards for these products. To expand that rulemaking now to include 
transformers outside these ranges would impose a substantial burden on 
DOE, and would substantially delay the rulemaking by requiring that the 
Department go back to the beginning of the process of evaluating 
standards for these additional transformers. Neither DOE nor 
stakeholders contemplated that the standards rulemaking would cover 
these additional transformers. To the contrary, as indicated above, 
interested parties had reached a consensus as to the transformers to be 
covered in the standards rulemaking, and expect that DOE will now move 
as promptly as possible to promulgate standards for these transformers.
    Another possibility would be for the Department to attempt to 
preserve the current scope of the standards and test procedure 
rulemakings by pursuing exclusion from the definition of distribution 
transformer, under 42 U.S.C. 6291(35)(B)(iii), of transformers with 
capacities outside the ranges specified in the SNOPR definition. This 
too would delay the rulemakings. For DOE to gather relevant information 
and assess whether transformers above and below the SNOPR's capacity 
ranges meet the criteria in 42 U.S.C. 6291(35)(B)(iii), would be 
burdensome and time consuming. And if DOE determined exclusion of these 
transformers to be warranted, it would have to undertake additional 
rulemaking proceedings to achieve such exclusion. Moreover, if DOE were 
to conclude that these transformers do not meet the criteria for 
exclusion, DOE would be in essentially the same position it is in now.
    The Department is determined to avoid further delays in the 
rulemakings on standards and test procedures for distribution 
transformers. Therefore, it does not wish either to expand these 
rulemakings to cover transformers outside the SNOPR's capacity ranges, 
or to pursue at this time exclusion of such transformers from the 
definition of distribution transformer. Furthermore, the transformers 
within these capacity ranges clearly are within the new EPCA definition 
of distribution transformer, so the Department is authorized to pursue 
standards for them, and DOE believes there are ample grounds to 
conclude that such standards are warranted under the criteria of 
section 346(a) of EPCA, 42 U.S.C. 6317(a).
    For these reasons, Sec.  431.192 of today's final rule modifies the 
EPCA definition of distribution transformer that was recently 
incorporated into the DOE rules by adding to it the kVA capacity 
limitations in the SNOPR definition. This definition will not include, 
as it could not, any transformers excluded from the EPCA definition, 
and today's test procedure and any standards rulemaking will not cover 
such transformers. The Department is adopting this definition, with its 
capacity limitations, for the purpose of delineating the coverage of 
today's rule, as well as the transformers that will be evaluated in the 
current standards rulemaking for distribution transformers. The 
inclusion of the capacity limitations in today's definition does not 
mean that DOE has concluded that the EPCA definition of distribution 
transformer includes such limitations. Rather, at some point after 
completion of the current rulemakings as to distribution transformers, 
the Department intends to evaluate transformers with larger and smaller 
capacities than those included in today's definition, review how EPCA 
should be construed with regard to those transformers, and decide what 
if any action to take with regard to adoption of efficiency 
requirements for such transformers. If DOE adopts efficiency 
requirements for any of these transformers, it would amend the 
definition of ``distribution transformer'' in its regulations 
accordingly.
    Finally, the capacity limitations in today's definition of 
``distribution transformer'' will have no effect on the existing 
requirements for low-voltage dry-type distribution transformers. EPCA 
sets forth a definition and standards for this equipment, 42 U.S.C. 
6291(38) and 6295(y), which DOE incorporated into its regulations at 10 
CFR sections 431.192 and 431.196(a). Because the definition states that 
a ``low-voltage dry-type distribution transformer'' is a ``distribution 
transformer'' that meets certain criteria, the addition of capacity 
limits to the definition of ``distribution transformer'' could be read 
as affecting what constitutes a ``low-voltage dry-type distribution 
transformer'' under the regulation. As stated above, however, the 
maximum limits for primary and secondary voltages of 34.5 kilovolts and 
600 volts, respectively, in EPCA's definition of ``distribution 
transformer,'' in effect limit transformers that meet that definition 
to those with a maximum capacity of approximately 3750 to 5000 kVA. 
Similarly, one of the criteria for a ``low-voltage dry-type 
distribution transformer'' is that its primary voltage not exceed 600 
volts, 10 CFR section 431.192, which contemplates a secondary voltage 
much lower than 600 volts. The obvious effect of this is that a 
transformer will be a ``low-voltage dry-type distribution transformer'' 
under the regulations only if its maximum capacity is far less than 
3750 kVA, and in all likelihood less than the 2500 kVA maximum in 
today's definition of distribution transformer. In addition,

[[Page 24977]]

EPCA and DOE rules prescribe standards for low-voltage dry-type 
distribution transformers only with kVA's within the range of 15 to 
1000, 42 U.S.C. 6295(y) and 10 CFR section 431.196(a), which are within 
the 15 to 2500 kVA range that today's definition of ``distribution 
transformer'' incorporates for dry-type transformers. For these 
reasons, the capacity limitation in today's definition of 
``distribution transformer'' has no impact on the current DOE and EPCA 
requirements for low-voltage dry-type distribution transformers.
2. Incorporation and Definition of EPCA's Exclusions--General
    As indicated above, DOE incorporated into its rules the new EPCA 
definition of distribution transformer, including the language listing 
specific types of excluded transformers and authorizing DOE to add to 
that list. 70 FR 60416-17. Upon further review, the Department has 
decided to adopt in Section 431.192 of today's rule several editorial, 
clarifying and format changes to the language concerning the 
exclusions.
    To begin with, this language states that the term ``distribution 
transformer'' does not include ``a transformer that is designed to be 
used in a special purpose application and is unlikely to be used in 
general purpose applications, such as [the list of specifically 
excluded transformers]'' (42 U.S.C. 6291(35)(B)(ii); 70 FR 60416-17) At 
first reading, this language appears to exclude unspecified types of 
transformers that meet the criteria just quoted, and to introduce a 
list consisting of specific illustrations of the transformers excluded. 
However, the very next paragraph of the definition states that DOE may, 
``by rule,'' exclude ``any transformer not listed'' which meets 
criteria that, in substantial part, are virtually identical to the 
criteria just quoted. (42 U.S.C. 6291(35)(B)(iii); 70 FR 60416) If the 
definition were read as excluding any transformer, in addition to those 
specifically listed, that met these criteria, this would obviate and 
render null the provision authorizing DOE to exclude additional 
transformers that meet these criteria, but only through rulemaking. The 
Department believes, however, that the soundest construction of these 
provisions is that transformers not specifically listed in the 
definition can be excluded only through a DOE rulemaking, thus 
providing certainty as to which transformers are covered at any given 
point in time. Use of the language quoted at the beginning of this 
paragraph to introduce the list of specifically excluded transformers 
serves to describe those transformers, and helps indicate the types of 
transformers the statute authorizes DOE to exclude by rule. Therefore, 
because this provision does not actually delineate excluded 
transformers, and in order to avoid confusion as to the function of 
this language, DOE in today's rule has amended section 431.192 by 
excluding it.
    As just indicated, DOE incorporated into its definition of 
distribution transformer language from EPCA that authorizes DOE to add 
to the list of excluded transformers. (42 U.S.C. 62912(35)(B)(iii); 70 
FR 60416-17) Because this language authorizes action by DOE and does 
not actually describe transformers that are not ``distribution 
transformers,'' upon further reflection the Department believes that 
the language need not be included in the definition in the DOE rules. 
Therefore, the Department has amended its definition of ``distribution 
transformer'' by omitting this language from section 431.92 of today's 
rule.
    As to the specific exclusions, the Department indicated when it 
adopted the EPCA definition, 70 FR 60408, that the definition uses 
incorrect terms in its exclusions of ``Uninterruptible Power System 
[UPS] transformer, impedance transformer, * * * [and] sealed and 
nonventilating transformer.'' (42 U.S.C. 6291(35)(B)(ii)) In accordance 
with its expressed intention to address such minor drafting problems in 
future rulemaking proceedings, where Congress has not already done so, 
70 FR 60408, in today's rule DOE is amending its definition of 
distribution transformer to correct use of these terms. First, UPS 
transformers are commonly referred to as ``Uninterruptible Power Supply 
transformers,'' not ``Uninterruptible Power System transformers,'' and 
therefore DOE adopts the former term in today's rule. Second, every 
transformer has an impedance, but only transformers with impedances 
outside of normal ranges, i.e., ``special-impedance'' transformers, 
warrant exclusion from standards. The Department had proposed to 
exclude such transformers from its definition of distribution 
transformer in the SNOPR, and NEMA excludes them from coverage of NEMA 
TP 1 and TP 2. Therefore, DOE construes EPCA as excluding ``special 
impedance'' transformers, and today's rule substitutes that term for 
``impedance'' in the list of exclusions. Third, IEEE standards define 
``sealed'' transformers separately from ``nonventilated'' transformers, 
treating them as two different types of transformers. The definitions 
are such that it would be highly unlikely for a particular transformer 
to be both ``sealed'' and ``nonventilated.'' In the SNOPR, DOE treated 
them as two separate exclusions from the term ``distribution 
transformer,'' as it believes is appropriate. In light of the 
foregoing, DOE construes EPCA as containing separate exclusions for 
sealed and nonventilated transformers, and today's rule so provides.
    The Department has also changed the format for the specific 
exclusions in section 431.192 of today's rule, and adopted the approach 
in the SNOPR, by placing the exclusions in a numbered list, rather than 
simply listing them seriatim in a single paragraph. The Department 
believes this will make the rule easier to read and use.
    Finally, conforming to the approach in EPCA, DOE's recently adopted 
rule lists the 12 types of transformers it excludes from the term 
``distribution transformer,'' but contains no definition for any of 
them. 70 FR 60416-17. In the SNOPR, DOE proposed definitions for the 
transformers it proposed to exclude. The Department believes such 
definitions are warranted because they help to clarify exactly which 
transformers are covered. Today's rule includes seven definitions drawn 
from IEEE standards, and five that DOE developed based on industry 
catalogues, practice and nomenclature. DOE believes they represent a 
reasonable construction of the EPCA exclusions. Except as indicated in 
the discussion below of the definitions of special impedance, testing 
and grounding transformers, they are the same definitions DOE proposed 
in the SNOPR.
3. Specific EPCA Exclusions
a. Transformers With Tap Ranges of 20 Percent or More and Special 
Impedance Transformers
    EPCA and the Department's recently adopted rule exclude from the 
definition of ``distribution transformer'' transformers with ``multiple 
voltage taps, the highest of which equals at least 20 percent more than 
the lowest.'' 42 U.S.C. 6291(35)(B)(i); 70 FR 60416. The Department 
reads this language as excluding transformers with a tap range of 20 
percent or more. It is similar to the exclusion in the SNOPR of 
transformers with a tap range greater than 15 percent. The language 
EPCA uses for this exclusion, however, is ambiguous.
    Each distribution transformer with multiple voltage taps has a 
nominal voltage at which it normally operates and other voltages 
(taps), typically

[[Page 24978]]

above and below its nominal voltage at which it can also operate. The 
voltage taps enable the transformer to be connected to distribution 
lines at these other voltages. The tap range represents the difference 
between the highest and lowest voltage taps relative to the nominal 
voltage, expressed as a percentage. It is unclear whether, under the 
EPCA exclusion, a transformer's tap range is determined by computing 
the percentage of the voltage difference between its lowest and highest 
voltage taps relative to the voltage of the lower tap, or, as the 
industry has traditionally done, by adding the sum of the percentages 
by which the highest and the lowest voltage taps deviate from the 
nominal voltage. (The traditional industry method is equivalent to the 
percentage of the difference between the lowest and highest voltage 
taps relative to the nominal voltage.) These two approaches generally 
yield two different results for tap range value for any given 
transformer with multiple voltage taps. For example, a 600-volt primary 
transformer with two 2.5-percent taps above and four 2.5-percent taps 
below the nominal, with the highest tap being 630 volts and the lowest 
540 volts, would normally be referred to as having a tap range of 15 
percent (i.e., 6 times 2.5 percent, or 90 volts as a percentage of 600 
volts = 15 percent). Similarly, a 600-volt primary with three 2.5-
percent taps above and three 2.5-percent taps below the nominal, with 
the highest tap being 645 volts and the lowest 555 volts, would also be 
referred to under the traditional industry approach as having a tap 
range of 15 percent. However, if the tap percentages for these 
transformers were calculated as a percentage of the voltage rating of 
the lowest tap (540 volts and 555 volts in these examples), these two 
transformers would have a tap range of 16.2 percent and a 16.7 percent, 
respectively.
    The Department believes that EPCA's exclusion of transformers with 
a tap range of 20 percent or more is best construed as reflecting 
standard industry practice, such that tap ranges do not vary with the 
voltage rating of the lowest tap. Rather, tap range should be 
calculated, and excluded transformers identified, based on the industry 
practice of calculating the transformer's percent tap range relative to 
the nominal voltage of the transformer. Accordingly, the Department 
interprets EPCA as excluding transformers from the definition of 
``distribution transformer'' when the aggregate of the transformer's 
highest to lowest tap voltages, relative to the nominal voltage, equals 
at least 20 percent. In section 431.192 of today's rule, the Department 
has incorporated this interpretation into its regulations by adding 
clarifying language to amend the regulation containing this exclusion 
that it adapted from EPCA in 70 FR 60416.
    The Department also notes that EPCA includes this exclusion in a 
separate paragraph, rather than in the list that comprises the other 
exclusions from the definition of ``distribution transformer.'' (42 
U.S.C. 6291(35)(B)(i)-(ii)) See 70 FR 60416. To present this exclusion 
in the same format as the other exclusions, in section 431.192 of 
today's rule the Department has added ``Transformer with Tap Range of 
20 percent or more'' to the list of exclusions and defined that term 
using the EPCA language that contains the exclusion, modified as just 
indicated.
    As indicated above, the Department had proposed in the SNOPR to 
exclude transformers with tap ranges greater than 15 percent. 69 FR 
45110, 45420-22. Pemco, a manufacturer, expressed the concern that, if 
the Department declines to adopt efficiency standards for distribution 
transformers with a tap range of greater than 15 percent (currently the 
standard tap range for low voltage dry-type transformers), 
manufacturers might begin producing transformers with a slightly larger 
tap range, and such transformers would not be covered by standards. 
(Pemco, No. 48 at p. 2) That could create a significant loophole under 
the regulations. Since the 20-percent tap range is larger than the 
previously proposed 15-percent range, exclusion of transformers with 
tap ranges of at least 20 percent should reduce the risk that 
transformers with slightly larger tap ranges would be produced in order 
to avoid coverage. But that risk will not be completely eliminated.
    The exclusion of special impedance transformers, as provided in 
EPCA, as recently incorporated by DOE into 10 CFR section 431.192, and 
as previously proposed by DOE in the SNOPR, raises a similar issue. The 
issue is brought into focus by DOE's proposed definition for these 
transformers in the SNOPR. The proposed definition specified a normal 
impedance range for each standard kVA rating, and stated that a 
``special-impedance transformer'' would be any transformer with an 
impedance outside the applicable range. Any such transformer would not 
be a ``distribution transformer'' covered by the proposed rule. 69 FR 
45510-11, 45520-22. No commenter objected to this exclusion, and only 
one specifically addressed it. Howard Industries recommends that DOE 
replace its proposed normal impedance ranges with ranges included in 
Howard's comments, which are more in line with ranges ANSI uses to 
delineate special impedance transformers and on which most utility 
systems are based. (Howard, No. 55 at p. 3) For most kVA levels, DOE's 
proposed ranges are broader than Howard's. Hence, DOE's ranges would 
result in exclusion of fewer transformers, by classifying fewer as 
``special impedance.'' In its revised test procedure document, NEMA TP 
2-2005, NEMA incorporated DOE's proposed normal impedance ranges. 
(NEMA, No. 60 Attachment 1 at pp. 5-6)
    The Department is concerned that some transformers designed for 
electricity distribution could be manufactured with impedances outside 
normal ranges so that they would not be subject to otherwise applicable 
efficiency standards. Such transformers could be less expensive to 
manufacture than normal impedance transformers manufactured in 
compliance with the standards, and therefore could have a competitive 
advantage over standards-compliant distribution transformers. If this 
occurred, it would subvert the standards. At best, the manufacturer(s) 
of such new, non-complying transformers would sell them in place of 
complying products they would otherwise have sold, and the product 
would have a share of the market for which DOE analysis demonstrated 
that standards were technologically feasible and economically 
justified. This would reduce energy savings below the levels that 
standards under EPCA are designed to achieve, and reduce the benefits 
transformer consumers and the public would realize from the standards. 
At worst, to avoid significant losses of market share to the competing, 
non-complying transformer, other manufacturers would be forced to 
produce the same type of non-complying unit. In that case, all or most 
of the benefit of standards could be lost.
    The Department believes that use of the impedance ranges in the 
proposed rule, to delineate special impedance transformers, is a 
reasonable implementation of EPCA's exclusion of these transformers. 
This is the same approach, discussed above, that EPCA follows in its 
exclusion of transformers with non-standard tap ranges, in that only 
transformers that are considerably outside the normal ranges are 
excluded from coverage. To construe EPCA otherwise, that is, to 
construe it as excluding from coverage any transformer that falls 
outside the current, standard normal impedance ranges, could spawn a 
new generation of distribution transformers with impedances outside 
these ranges, which

[[Page 24979]]

would not be subject to Federal efficiency standards and test 
procedures. As just mentioned, this could subvert DOE's energy 
efficiency standards. NEMA's inclusion of DOE's proposed impedance 
ranges in the revised TP 2 standard provided to the Department, and the 
fact that only one commenter objected to them, indicate they are a 
sound basis for delineating the special impedance transformers that are 
excluded from coverage under today's rule and DOE's efficiency 
standards. Therefore, section 431.192 of today's rule retains the 
SNOPR's proposed definition of the ``special-impedance transformers'' 
excluded from the term ``distribution transformer.''
    The Department recognizes that this approach may not prevent 
attempts to circumvent its efficiency requirements through manufacture 
of distribution transformers that appear to, or do, fall just within 
this exclusion or the exclusion of transformers with tap ranges of 20 
percent or more. Such transformers could conceivably be manufactured 
for use in standard applications to distribute electricity in power 
distribution systems, but with efficiencies below those required by 
DOE's standards. Indeed, other exclusions from today's definition of 
distribution transformer could also be exploited to justify manufacture 
of transformers, for standard distribution applications, that do not 
meet DOE standards. The Department believes one such example may be the 
exclusion for drive (isolation) transformers. Such transformers can be 
similar to standard distribution transformers. A manufacturer might be 
able to produce and market, for standard distribution uses, a 
transformer that does not meet DOE efficiency standards but that 
clearly, or arguably meets, DOE's definition of ``drive (isolation) 
transformer,'' and claim that it is not a ``distribution transformer'' 
as defined by DOE.
    The Department intends to strictly and narrowly construe the 
exclusions from the definition of ``distribution transformer.'' It will 
also take appropriate steps, including enforcement action if necessary, 
if any manufacturer or other party erroneously invokes one of the 
exclusions as a basis for marketing a transformer that is a 
``distribution transformer'' under today's rule but does not meet DOE 
standards. Moreover, to the extent transformers that do fall within the 
exclusions begin to be marketed for standard distribution applications, 
or find widespread use in such applications, DOE will examine whether 
re-defining the relevant exclusions, and/or legislative action, is 
warranted.
b. Testing Transformers
    EPCA, and DOE's recent rule, also exclude a ``testing transformer'' 
from the definition of distribution transformer, 42 U.S.C. 
6291(35)(B)(ii) and 70 FR 60416, as does section 431.192 of today's 
rule. The Department proposed this exclusion in the SNOPR. 63 FR 63363; 
69 FR 45510. No stakeholder commented on it, in response to either the 
NOPR or SNOPR, except that in its revised TP 2-2005 document, NEMA 
deleted the following sentence from the SNOPR's proposed definition of 
``testing transformer'': ``This type of transformer is also commonly 
known as an Instrument Transformer.'' (NEMA, No. 60 Attachment 1 at p. 
7) An instrument transformer, however, is a type of transformer used 
for extending the voltage and current ranges of measuring and control 
instruments--such as voltmeters, ammeters, wattmeters, and relays--and 
is not the same as a testing transformer that supplies power to test 
electrical equipment. The Department recognizes that it erroneously 
included this sentence in the SNOPR definition of testing transformer 
and has deleted it from today's rule.
    The Department believes that this error would not have lead 
stakeholders to infer that DOE had proposed to specifically exclude 
instrument transformers from the definition of ``distribution 
transformer'' in the SNOPR, for two reasons. First, the remainder of 
the proposed definition of testing transformer clearly did not include 
instrument transformers, and second, contrary to the incorrect 
sentence, testing transformers are not commonly known as instrument 
transformers. Nevertheless, to the extent the proposed rule may have 
been read to specifically exclude instrument transformers, DOE believes 
such an exclusion is unnecessary and unwarranted. The revised NEMA TP 
2-2005 contains no such exclusion. Moreover, an instrument transformer 
would be designed to handle less power than the lower capacity limits 
(10 kVA for liquid-immersed and 15 kVA for dry-type) in today's 
definition of distribution transformer, unless it was also designed to 
distribute electricity. In the former case, the transformer would not 
be covered under today's rule (or under the SNOPR) even absent a 
specific exclusion, rendering an exclusion unnecessary. In the latter 
case, it should be covered, and subject to DOE efficiency standards and 
test procedures, as a ``distribution transformer.'' Hence, there is no 
reason to consider further the exclusion of ``instrument transformers'' 
from today's definition of distribution transformer.
c. Grounding Transformers
    Finally, section 431.192 of today's final rule contains a 
clarifying modification to the SNOPR's definition of ``grounding 
transformer.'' That definition referred to ``[a]n autotransformer with 
a zig-zag winding arrangement.'' 69 FR 45521. The Department has since 
become aware that this language is internally inconsistent, because an 
autotransformer with a zig-zag winding cannot be an autotransformer as 
defined in the rule, nor does it meet industry's conventional 
understanding of the term. The Department used the term autotransformer 
in the proposed grounding transformer definition to describe a type of 
transformer that does not have a separate physical secondary winding 
(unlike a conventional transformer). But although a three-phase 
autotransformer has three coils constituting the primary winding only, 
and no separate secondary winding, a section of each primary coil is 
``tapped-off'' to create, in effect, a secondary winding. A grounding 
transformer, however, has only a primary winding, and no secondary 
winding output. In today's rule, in the definition of ``grounding 
transformer,'' the Department has replaced the reference to an 
autotransformer with a reference to a transformer with a primary 
winding and no secondary winding.
4. Other Exclusions Considered
    The bulk of the comments on the SNOPR's definition of distribution 
transformer advocated eliminating or narrowing exclusions DOE had 
proposed, or adding other exclusions. EPACT 2005 incorporated none of 
these exclusions into EPCA.
    In the SNOPR, DOE had proposed to exclude both harmonic mitigating 
transformers and K-factor (also referred to as ``harmonic tolerating'') 
transformers at K-13 and higher, largely based on its view that: (1) 
regulating them would not save significant amounts of energy, and (2) 
they are sufficiently expensive that there is little risk they would be 
purchased in place of more efficient transformers that would be subject 
to standards. 69 FR 45511, 45520-21. The Department also indicated its 
belief that few harmonic mitigating transformers would be commonly 
understood to be distribution transformers. 69 FR 45511. No commenter 
advocated retention of either exclusion, and several supported 
eliminating or narrowing them.

[[Page 24980]]

Supporting elimination of both exclusions, NEMA stated that the 
exclusions could be used to avoid efficiency standards. (NEMA, No. 39 
at p. 2 and No. 47 at p. 2; Public Meeting Transcript, No. 42.11 at p. 
22; NEMA No. 51 at p. 2) The Oregon Department of Energy raised doubts 
that these transformers would be unable to meet standards and saw no 
rationale for excluding them. (ODOE, No. 54 at p. 2) Harmonics Limited 
believes the market for them is large and growing, that use of K-rated 
transformers to circumvent existing standards has resulted in greater 
energy consumption, and harmonic transformers can both comply with 
standards and address harmonics issues. (Harmonics Limited, No. 50 at 
p. 1) ACME and Pemco advocated elimination of the exclusion for K-
factor transformers (Public Meeting Transcript, No. 42.11 at pp. 32-33; 
Pemco, No. 48 at p. 2), and EMS International Consulting, Inc. (EMS) 
advocated elimination of the exclusion for harmonic mitigating 
transformers. (EMS, No. 57 at p. 3) In addition, EMS recommended that 
DOE cover K-rated transformers (up to a certain level which EMS did not 
specify), and Federal Pacific recommended narrowing the K-factor 
exclusion for transformers rated up to 300 kVA and broadening it for 
transformers above 300 kVA, both on grounds similar to those advanced 
by commenters who advocated its elimination. (EMS, No. 57 at p. 2; FPT, 
No. 44 at pp. 2-3 and No. 52 at p. 2)
    Based on these comments, and upon further review, DOE has concluded 
there is not a sufficient basis at this point to exclude harmonic 
mitigating or K-factor transformers from the definition of distribution 
transformer. In essence, the Department proposed in the SNOPR to 
exclude these transformers on the grounds that they are not 
``distribution transformers,'' and that energy conservation standards 
for them would fail to meet the EPCA criteria in 42 U.S.C. 6317(a)(1) 
because such standards would not save substantial amounts of energy 
and/or be economically justified. Concerning the first point, as 
discussed above, EPCA, as amended in EPACT 2005, now defines the term 
``distribution transformer.'' Harmonic mitigating and K-factor 
transformers do not per se fail to meet the numerical criteria in this 
definition, nor are they in the definition's list of excluded 
transformers. (42 U.S.C. 6291(35)(A) and (B)(i)-(ii))
    EPCA, as recently amended, now authorizes DOE, however, to exclude 
by rule any transformer if it is designed for a special application, if 
it is unlikely to be used in a general purpose application, and if 
significant energy savings would not result from applying standards to 
it. (42 U.S.C. 6291(35)(B)(iii)) DOE previously relied on general 
information to support the views expressed in the SNOPR that harmonic 
mitigating and K-factor transformers would not be used for general 
purpose distribution applications, and that standards for them would 
not save significant amounts of energy. However, these conclusions were 
somewhat negated by the comments that these transformers could be sold 
in place of distribution transformers that are subject to standards, 
and that their use is increasingly common. Also, the Department is not 
aware of any more concrete information or analyses that address whether 
standards for these transformers could save energy. Thus, the 
Department now has no basis for excluding them under the new criteria 
in section 42 U.S.C. 6291(35)(B)(iii). For these reasons, DOE cannot 
conclude at this point that harmonic mitigating or K-factor 
transformers fail to meet the new EPCA definition of ``distribution 
transformer.''
    Concerning the issue of whether these transformers should be 
excluded from DOE's definition of distribution transformer on the 
ground that energy conservation standards for them would not meet the 
criteria in 42 U.S.C. 6317(a)(1), as just set forth, there is 
insufficient basis to conclude that such standards would fail to save 
substantial amounts of energy. Furthermore, comments that harmonic 
mitigating and K-factor transformers could be manufactured to be in 
compliance with applicable efficiency standards without excessive cost 
suggest that standards for this equipment might well be economically 
justified. As with the issue of potential energy savings, the 
Department is not aware of any concrete information or analyses that 
suggest that standards for K-factor and harmonic mitigating 
transformers are not economically justified. Thus, the Department 
believes there is insufficient basis to conclude at this point that 
standards for these transformers would fail to meet the criteria in 42 
U.S.C. 6317(a)(1).
    Some commenters suggest adding other exclusions to the definition 
of distribution transformer. Federal Pacific recommends that mining 
transformers (transformers installed inside a mine, inside equipment 
operated in a mine, or as a component of underground-digging or 
tunneling machinery) be excluded from the application of standards, 
because of their radically different loss characteristics and special 
dimensional constraints. (FPT, No. 52 at p. 2) Aligning with that 
comment, NEMA excludes mining transformers from its revised test 
procedure, TP 2-2005. (NEMA, No. 60, Attachment 1 at p. 1 and p. 4) 
Pemco asserts the need for an exclusion for transformers subject to 
dimensional, physical or design constraints, such as height limits, low 
temperature rise, special sound level requirements, weight limits, and 
suitability for high altitudes, which, according to Pemco, render it 
physically impossible or cost-prohibitive for these transformers to 
meet an efficiency standard. (Pemco, No. 48 at p. 1) Pemco also states 
that an exclusion is needed for retrofit transformers that have to be 
exactly the same as the ones they are replacing. (Pemco, No. 48 at p. 
1-2) Similarly, Howard Industries advocates an exclusion for retrofit 
transformers, particularly underground and subway style transformers, 
on the grounds that they are subject to severe physical or electrical 
constraints, and would be unable to also meet energy conservation 
standards. (Public Meeting Transcript, No. 42.11 at p. 36; Howard, No. 
55 at p. 3) However, although NEMA views the lack of an exclusion for 
retrofit transformers as problematic, it did not advocate such an 
exclusion because it has not formulated a definition or solution for 
this problem. (Public Meeting Transcript, No. 42.11 at p. 35)
    In the SNOPR, DOE did not propose to exclude any of the foregoing 
types of transformers from its proposed definition of distribution 
transformer. And as with K-factor and harmonic mitigating transformers, 
EPCA excludes none of them from its definition of distribution 
transformer. (42 U.S.C. 6291(35)(A) and (B)(i)-(ii)) Furthermore, the 
commenters who supported these additional exclusions have provided 
neither data as to the energy savings potential of standards for these 
transformers, nor information as to the likelihood they could be used 
in general purpose applications, and the Department is not aware of any 
concrete information or analyses that address these points. Therefore, 
the Department has no basis for excluding any of the transformers 
discussed in this paragraph under section 321(35)(B)(iii) of EPCA. (42 
U.S.C. 6291(35)(B)(iii)) As to whether these transformers satisfy the 
criteria in 42 U.S.C. 6317(a)(1) for adopting test procedures and 
standards, the commenters have provided broad claims, but no technical 
or factual evidence, that addresses this issue.
    For these reasons, the Department has concluded that there is not a 
sufficient basis at this point to exclude harmonic mitigating or K-
factor transformers, or

[[Page 24981]]

transformers subject to dimensional, physical or design constraints 
(including mining transformers), from today's definition of 
distribution transformer, and the definition does not exclude them.
    Rather, DOE will revisit the issues of whether, and to what extent, 
these transformers should be subject to standards, and at what levels, 
during the standards rulemaking for distribution transformers. As set 
forth in the Determination notice, the Department can best address 
issues as to the technological feasibility, economic justification and 
potential energy savings of energy conservation standards in the 
standards rulemaking, particularly during evaluation of proposed 
standard levels. 62 FR 54810. For many products, such as the types of 
distribution transformers at issue here, the question of whether 
standards are warranted cannot adequately be addressed without detailed 
information and analysis. Once the Department has decided to propose 
additional standard levels for distribution transformers, and has 
provided its analysis of the levels it has considered in depth, 
stakeholders will have an opportunity to comment. They can provide 
factual information and analysis on issues such as whether the proposed 
standard levels, or other levels, are warranted for particular classes 
of transformers, including the types just discussed. These comments 
could also address whether some types of transformers should be 
completely or partially excluded from standards, including, for 
example, whether a portion of K-factor transformers should be excluded 
as advocated by Federal Pacific. To the extent information developed 
during the standards rulemaking warrants exclusion of any type of 
transformers from coverage of the new standards (and test procedures), 
the Department will modify its definition of ``distribution 
transformer'' accordingly.
5. Rebuilt or Refurbished Distribution Transformers
    The Department did not specifically address in the SNOPR whether 
today's test procedure, as well as efficiency standards for 
distribution transformers, would apply to rebuilt distribution 
transformers (i.e., units on which one or more windings have been 
replaced), or to used or repaired distribution transformers. Nor does 
EPCA specifically address this question. Several commenters stated that 
the requirements should apply to rebuilt transformers, commonly 
referred to also as refurbished transformers. EMS and HVOLT stated that 
coverage of rebuilt units is necessary to close a potential loophole 
(EMS, No. 57 at p. 3; HVOLT, No. 53 at p. 3), and ERMCO stated that 
failure to cover rebuilt units might enable end-users to avoid 
standards by always rewinding failed units. (ERMCO, No. 49 at p. 2) 
Manufacturers appeared to be concerned that the increased cost of new, 
standards-compliant transformers would cause some customers to either 
purchase rebuilt, instead of new, transformers or rebuild existing 
transformers they already own. The Oregon Department of Energy agreed 
that rebuilt transformers should be required to meet new standards, 
indicating that high-quality rewinding practices can produce products 
that would meet standards while poor quality work can seriously degrade 
performance. (ODOE, No. 54 at p. 2) Some commenters also advocated 
coverage of used and/or repaired distribution transformers. (Howard, 
No. 55 at p. 3; EMS, No. 57 at p. 3)
    EPCA, in essence, seems to require only new distribution 
transformers, that have not been sold to end users, to meet Federal 
efficiency requirements. (42 U.S.C. 6302, 6316(a) and 6317(a)(1)) Thus, 
DOE probably lacks authority to require that used and repaired 
transformers comply with its test procedures and standards. The same 
may be true for rebuilt transformers, although for them a genuine issue 
does exist as to DOE's authority. Generally, EPCA provides that 
products, when ``manufactured,'' are subject to efficiency standards. 
(42 U.S.C. 6295(b)-(i) and 6313) It is arguable, but by no means clear, 
that rebuilt transformers could be considered to be ``manufactured'' 
again when they are rebuilt, and therefore be classified as new 
distribution transformers subject to DOE test procedures and standards. 
If, however, rebuilt products cannot be classified as newly 
manufactured, DOE would be subject to the same limitation on its 
authority to regulate them as applies to used and repaired products. In 
addition, contrary to the suggestion of some commenters that DOE 
regulate the efficiency of distribution transformers that their owners 
have re-wound, and where the transformer is not re-sold, EPCA provides 
authority to regulate only products that are sold, imported or 
otherwise placed in commerce. (42 U.S.C. 6291, 6311, and 6317(f)(1))
    Throughout the history of its appliance efficiency program, DOE has 
not sought to regulate used units that have been re-conditioned or 
rebuilt, or have undergone major repairs. Regulating this part of the 
market, including the enforcement of efficiency requirements, could be 
an exceedingly complex and burdensome task. By and large, the 
Department believes EPCA indicates a Congressional intent that DOE 
focus on the market for new products, and believes that this is where 
the largest energy savings can be achieved. For distribution 
transformers in particular, the Department understands that at present 
rebuilt transformers are only a small part of the market. Moreover, the 
core dimensions of existing units are fixed, whereas for many newly 
manufactured transformers the dimensions of existing models could be 
enlarged in order to allow their efficiencies to increase. Therefore, 
at least initially, any standard for rebuilt transformers would likely 
have to be lower than for comparable newly manufactured units, and 
given the current size of the refurbished transformer market, it 
appears that significant energy savings could not be achieved by 
adopting standards for them.
    For all of these reasons, the Department does not intend to apply 
its standards and test procedures to used, repaired and rebuilt 
distribution transformers. Nevertheless, the Department recognizes that 
there may be some validity to the concerns raised by commenters about 
possible substitution of rebuilt for new transformers. If conditions 
change--for example, if rebuilt transformers become a larger segment of 
the transformer market--DOE will reconsider its decision not to subject 
them to energy conservation requirements.
6. Coverage of Liquid-Filled Transformers
    Finally, Howard Industries suggested, with regard to liquid-filled 
transformers, that the utility, municipal, and co-op segment of the 
market not be subject to mandatory standards, because it already uses 
life-cycle cost methods in purchasing products, and that only the 
commercial and industrial segment be subject to such standards. 
(Howard, No. 55 at p. 4) This is an interesting suggestion, but the 
Department believes it is untenable because the distribution 
transformers used in these two market segments are not sufficiently 
different from one another. If the Department were to adopt efficiency 
requirements for transformers currently sold in one sector but not the 
other, DOE believes that the transformers it left unregulated would 
promptly find their way into the regulated market. The Department is 
charged with prescribing test procedures and energy conservation 
standards for those distribution transformers for which it determines 
standards are technologically feasible

[[Page 24982]]

and economically justified and would result in significant energy 
savings. Liquid-immersed distribution transformers sold into the 
utility, municipal and co-op segments of the market are ``distribution 
transformers'' as defined in section 321(35) of EPCA, and, because they 
clearly are designed for general purpose applications, DOE could not 
exclude them under paragraph (B)(iii) of that section. (42 U.S.C. 
6291(35)) Moreover, in October 1997, the Department made a 
determination that energy conservation standards for liquid-immersed 
distribution transformers would appear to be technologically feasible 
and economically justified, and to result in significant energy 
savings. 62 FR 54816. For these reasons, today's definition of 
``distribution transformer'' does not exclude liquid-immersed 
transformers, nor any subset of these transformers destined for any 
particular end-user or market segment.

C. Test Procedure for Distribution Transformers

1. General Discussion
    The Department developed the test method in today's final rule 
(Appendix A to Subpart K of Part 431) in order to have a single, 
primary reference that would clearly set forth all testing requirements 
for distribution transformers that may be covered by EPCA energy 
conservation standards. Almost in its entirety, the test method closely 
follows NEMA TP 2-1998 and the following four widely used IEEE 
standards: (1) IEEE C57.12.90-1999, ``IEEE Standard Test Code for 
Liquid-Immersed Distribution, Power and Regulating Transformers and 
IEEE Guide for Short Circuit Testing of Distribution and Power 
Transformers,'' (2) IEEE C57.12.91-2001, ``IEEE Standard Test Code for 
Dry-Type Distribution and Power Transformers,'' (3) IEEE C57.12.00-
2000, ``IEEE Standard General Requirements for Liquid-Immersed 
Distribution, Power and Regulating Transformers,'' and (4) IEEE 
C57.12.01-1998, ``IEEE Standard General Requirements for Dry-Type 
Distribution and Power Transformers Including those with Solid Cast 
and/or Resin Encapsulated Windings.''
    As discussed in the SNOPR, the DOE did not propose to adopt NEMA TP 
2-1998 verbatim as the DOE test method because of concerns about 
whether TP 2-1998 was sufficiently clear, detailed and accurate to 
serve as the DOE test procedure. 69 FR 45508-09. The Department had 
also identified problems with the clarity and level of detail in TP 2-
1998 in the 1998 proposed rule. 63 FR 63362. Nor did the Department 
propose to incorporate the four IEEE standards by reference. As stated 
in the SNOPR, that would require users to consult several reference 
documents in order to construct the test procedure, whereas having a 
single reference test procedure would reduce the potential of 
misinterpreting testing requirements and would enhance the convenience 
to users. In addition the IEEE standards include test methods not only 
for distribution transformers, but also for much larger power 
transformers that are not covered by the DOE test procedure. 
Nevertheless, the Department relied heavily on techniques and methods 
from NEMA TP 2-1998 and the four IEEE standards in developing the 
proposed test procedure and today's final test procedure.
    EPACT 2005, which the President signed into law on August 8, 2005, 
amended EPCA in effect to direct the Department to develop a test 
procedure for distribution transformers that is ``based on'' NEMA TP 2-
1998. (42 U.S.C. 6293(b)(10)). In the SNOPR, DOE stated that it had 
``adapted virtually all of the provisions of the [proposed ] test 
procedure from NEMA TP 2[-1998] and the * * * four widely used IEEE 
standards'' just cited, and had used NEMA TP 2-1998 to develop the 
proposed test procedure. 69 FR 45508. The Department did not receive 
any comments from stakeholders indicating that they took issue with 
these statements. As stated above, today's testing methods are largely 
the same as those proposed in the SNOPR. Thus, as also set forth above, 
NEMA TP 2-1998 and the IEEE standards are the bases for these test 
methods. Indeed, because NEMA TP 2-1998 is based on the IEEE standards, 
and represents an attempt to incorporate them into a single document, 
any test method that incorporates the substance of these standards 
would conform to TP 2-1998. Furthermore, today's test methods and those 
in NEMA TP 2-1998 are entirely consistent with one another. For all of 
these reasons, it can be fairly stated that today's test procedure is 
``based on'' NEMA TP 2-1998, within the meaning of 42 U.S.C. 
6293(b)(10), and satisfies the Congressional intent that the DOE test 
procedure reflect the content of TP 2.\6\
---------------------------------------------------------------------------

    \6\ Although NEMA TP 2-1998 contains a sampling plan for 
establishing compliance with prescribed efficiency levels, the 
compliance sampling plan in today's rule, which is discussed in 
section II-E below, is not based on the plan in TP 2. EPACT 2005 
mandates that the Department use 12 industry or voluntary test 
procedures, each for a different type of product, as the basis for 
DOE test procedures for those products. All contain test methods, 
but NEMA TP 2-1998 appears to be the only one that contains a 
sampling plan. Moreover, for the reasons explained in the SNOPR, 
that sampling plan is inconsistent with the standards and labeling 
requirements in EPCA for distribution transformers, and with basic, 
long-standing elements of DOE's appliance efficiency program. 69 FR 
45514. Congress gave no indication in enacting EPACT 2005 that it 
intended its mandate for use of NEMA TP 2-1998 to change EPCA's 
standards and labeling requirements, or the structure of DOE's 
program, for this product. For these reasons, DOE believes Congress 
intended to require that DOE's test methods for distribution 
transformers, but not its compliance sampling plan, be based on NEMA 
TP 2-1998. Accordingly, the Department construes 42 U.S.C. 
6393(b)(10) as not affecting the content of its compliance sampling 
plan for distribution transformers.
---------------------------------------------------------------------------

    In response to the SNOPR, several commenters requested that DOE 
rely on existing testing standards as much as possible, as it does for 
other products, instead of adopting a new stand-alone test procedure. 
(FPT, No. 44 at p. 7; Public Meeting Transcript, No. 42.11 at pp. 49, 
54-55) NEMA expressed concern that the Department's proposal differed 
significantly from the existing testing methods (NEMA TP 2-1998 and 
IEEE), and asserted that industry engineers would need to become 
experts in the new method, and that this could be a difficult, time 
consuming process. (Public Meeting Transcript, No. 42.11 at pp. 49-51, 
53, 60) The Department recognizes that there will be some burden on 
manufacturers resulting from today's stand-alone test procedure. This 
burden, however, should be minimal. The test methods in the DOE test 
procedure are virtually identical to those in the TP 2-1998 and IEEE 
standards, and require the same steps for determining losses and 
calculating efficiency. Comments from stakeholders offered no specifics 
as to why use of the DOE test procedure would be burdensome for 
manufacturers and identified no specific provisions in DOE's proposed 
test procedure that deviate from the TP 2-1998 or IEEE standards. 
Furthermore, in NEMA's revised TP 2 document, TP 2-2005, the test 
method closely parallels the SNOPR rule language. (NEMA, No. 60, 
Attachment 1) This indicates that, upon further reflection, NEMA 
believes use of DOE's proposed test procedure would not be burdensome 
for manufacturers.
    Federal Pacific states that manufacturers will still be required to 
reference industry standards, in addition to DOE standards. (FPT, No. 
44 at p. 6) The Department believes that due to the similarities 
between today's test procedure and the TP 2-1998 and IEEE documents, a 
manufacturer following the DOE test procedure would also be consistent 
with NEMA TP 2-1998 and the IEEE test procedures.

[[Page 24983]]

Therefore, manufacturers would not have to take separate steps to 
assure compliance with each test procedure.
    Federal Pacific also asserts that a stand-alone DOE test procedure 
may become a problem if IEEE, ANSI, or NEMA adopt changes to their 
standards because the changes may have to be incorporated into the DOE 
test procedure. (FPT, No. 44 at pp. 6-7) This issue is not unique to 
transformers, and exists whether DOE has a stand-alone test procedure 
or incorporates by reference one or more industry standards, such as 
the IEEE test methods for transformers. The Department regulates many 
other consumer products and commercial equipment, all of which have 
test procedures. Some of these are DOE-developed, stand-alone test 
methods, and others incorporate by reference industry standards. Even 
in the latter situations, no change to an industry standard becomes 
part of the DOE test procedure unless and until the Department adopts 
it. In the event of an industry-consensus revision to the test methods 
for distribution transformers, the Department would consider all 
petitions from manufacturers seeking to incorporate those changes into 
today's test procedure.
    In sum, the Department continues to believe that having a single, 
reference test procedure document would enhance the convenience to 
users and reduce the potential for misinterpretation of testing 
requirements. Today's final rule adheres to that approach rather than 
incorporating provisions from the existing industry test procedures.
    Commenters did not disagree with the Department's decision not to 
adopt NEMA TP 2-1998, without modification, as the DOE test procedure. 
In written comments and during the SNOPR public workshop meeting, 
however, NEMA proposed that DOE, NEMA and other stakeholders work 
together to reach a consensus on needed revisions of TP 2, so that NEMA 
could revise it and DOE could then incorporate it by reference. (NEMA, 
No. 39 at p. 1; Public Meeting Transcript, No. 42.11 at pp. 22, 49-51, 
53, 56-57) NEMA has now completed its revision of TP 2, informing DOE 
that it obtained approval from its membership and adopted TP 2-2005 on 
September 19, 2005. (NEMA did not indicate whether other stakeholders 
were involved in this process.) NEMA proposes that DOE adopt the TP 2-
2005 document as its test procedure for distribution transformers, and 
reference it in the final rule for such test procedures. (NEMA, No. 60 
at p.1)
    The Department believes that such action would be inappropriate. 
The Department recognizes NEMA's efforts to revise TP 2 and appreciates 
NEMA's openness, including its submission of a draft TP 2-200X document 
in March 2005 (NEMA, No. 59 Attachment 1) and the final TP 2-2005 
document in September 2005 (NEMA, No. 60 Attachment 1). These 
submissions have made a definite contribution to this proceeding. As 
indicated elsewhere in this preamble, these submissions identified 
changes that were needed in the proposed rule, and that DOE has adopted 
in today's final rule. These changes include modification of the 
definition of load loss and several editorial changes. As also 
discussed in this preamble, however, stakeholder comments submitted in 
response to the SNOPR, as well as DOE's own review, have resulted in 
many other changes that clarify and improve the proposed test 
procedure. These additional changes include provisions for testing 
harmonic transformers, clarification of the language concerning test 
set neutrals, and an alternative to the proposed method for providing 
short-circuiting conductors. None of the additional changes are 
reflected in NEMA's final TP 2-2005 document. Moreover, TP 2-2005 
contains a number of changes from the SNOPR that should not be included 
in today's final rule, such as the exclusion of mining transformers. 
For these reasons, the Department is not incorporating TP 2-2005 as its 
test procedure rule for distribution transformers. That said, in the 
future, the Department would consider incorporating verbatim the NEMA 
test method in TP 2 so long as its substance conforms with the test 
method then in effect.
2. Specific Provisions of the Test Procedure
a. Testing Harmonic Transformers
    As discussed earlier in this notice, the Department proposed in the 
SNOPR to exclude both harmonic tolerating (K-factor) transformers with 
a K-factor of K-13 or greater and harmonic mitigating transformers from 
the definition of distribution transformer, but today's definition 
includes both of these types of transformers. Several stakeholders who 
recommended removal of the exemption for these transformers, also 
recommended that the test procedure should require testing using a 
linear load profile (K=1), namely, using the fundamental-frequency test 
current in the measurement of load loss. (NEMA, No. 47 at p. 1; NEMA, 
No 51 at p. 1; HVOLT, No. 53 at pp. 2-3; PQI, No. 56 at p. 3) Federal 
Pacific stated that absent an industry standard harmonic load profile, 
K=1 is the only available method for consistently testing transformers 
designed for harmonic currents. (Public Meeting Transcript, No. 42.11 
at pp. 33-34) Federal Pacific also commented that it uses K=1 to test 
K-factor transformers when a customer specifies a K-factor transformer 
but also wants it to meet TP 1 efficiency levels. (FPT, No. 44 at p. 2) 
When a harmonic transformer is tested with a linear load, however, its 
measured losses are lower than the losses it would experience under 
non-linear loads. Therefore, the efficiency rating that results from 
testing the transformer with a linear load will be higher than the 
actual efficiency of the harmonic transformer during normal operation 
(i.e., when the transformer is subject to non-linear loads). 
Nevertheless, as one commenter indicated, testing harmonic transformers 
at linear loads does offer a straight-forward testing method that 
avoids over-complicating the issue. (FPT, No. 44 at p. 3, and No. 52 at 
p. 2) The Department believes that if its efficiency standards become 
applicable to K-factor and harmonic mitigating transformers, more 
efficient harmonic transformers will be manufactured than if the 
standard did not apply to them. DOE agrees with the above comments, and 
therefore today's final rule, in Section 4.1 of the test procedure, 
requires that manufacturers test these transformers using fundamental-
frequency test current (corresponding to a linear (K=1)) load.
b. Determining Winding Temperatures
    Today's test procedure expands the options available to 
manufacturers for determining the winding temperature of liquid 
immersed transformers. IEEE C.57.12.90-1999 provides that the 
temperature of windings of a liquid-immersed transformer is assumed to 
be the same as the temperature of the liquid in which the windings are 
immersed. Adding specificity to this approach, the Department proposed 
in the SNOPR that the winding temperature of a liquid-immersed 
distribution transformer would be the average of two temperature 
sensing devices applied to the outside of the transformer tank, at top 
oil level and at the bottom of the tank. Howard Industries questioned 
the accuracy of this method for determining winding temperatures, and 
recommended instead that DOE require direct (internal) top and bottom 
measurement of the liquid temperature to determine winding temperature. 
(Howard, No. 45 at p. 1)

[[Page 24984]]

    The Department understands that the most common method in the 
distribution transformer industry for estimating the temperature of 
liquid immersed windings is by using thermocouples attached to the 
exterior of the transformer tank, as proposed in the SNOPR. 
Furthermore, as also proposed in the SNOPR, today's rule requires that 
winding temperature be measured only after certain conditions have 
stabilized, which provides greater assurance that these external 
measurements are a good estimate of the winding temperature. For these 
reasons, DOE believes Howard's recommendation that DOE require direct 
top and bottom measurement of the liquid could impose significant and 
unnecessary burdens on manufacturers. Nevertheless, the Department 
recognizes that such direct measurements would be at least as accurate 
as external measurements, and that testers who prefer to make direct 
measurements should be allowed to do so. Therefore, today's final rule 
allows manufacturers to determine the winding temperature using either 
exterior tank measurements or direct liquid measurements.
    The Department understands that testers normally make external tank 
temperature measurements using thermocouples that are designed to be 
thermally insulated from the surrounding environment. The use of 
insulated thermocouples reduces error in the temperature measurement, 
and offers greater accuracy in determining the winding temperatures. 
Therefore, the Department has modified the language in proposed section 
3.2.1 to clarify that these external temperature measurements must 
involve the use of insulated thermocouples.
    In addition, proposed section 3.2.1 would give manufacturers the 
choice of waiting to measure winding temperature until either (a) the 
windings have been under insulating liquid with no excitation and no 
current in the windings for four hours before the direct current (dc) 
resistance is measured; or (b) the temperature of the insulating liquid 
has stabilized, and the difference between the top and bottom 
temperature does not exceed 5 [deg]C. These conditions each provide 
assurance that the temperature of the windings has stabilized when 
manufacturers measure it. The Department took these two conditions from 
IEEE C57.12.90-1999, which requires that both be met when the tester 
measures the winding temperature. Howard Industries commented that the 
DOE test procedure should also require that both be met, to be 
consistent with the IEEE standard. (Howard, No. 45 at p. 2) The 
Department recognizes the value of being consistent with IEEE. However, 
the Department does not believe that for distribution transformers, 
meeting both conditions is necessary. The IEEE standard encompasses kVA 
ratings of transformers that are much larger (up to 500,000 kVA and 
larger) than those covered by today's final rule (no larger than 2,500 
kVA). The Department believes that for distribution transformers, which 
are relatively small compared to many of the kVA ratings addressed by 
IEEE, manufacturers can achieve accurate winding temperature readings 
if one of these two conditions is met. Therefore, the language in 
today's final rule does not require that both conditions be met.
    The Department has also made some clarifying and editorial changes 
to the language of section 3.2.2 in today's rule, which concerns 
determination of the winding temperature of dry-type transformers. 
Section 5.2 of IEEE C57.12.91-2001 allows for the determination of such 
winding temperatures, for both ventilated and sealed units, through 
either direct measurement or use of the ambient temperature of the test 
area. The IEEE standard permits the latter, however, only under certain 
conditions. The Department intended to incorporate the IEEE approach in 
section 3.2.2 of the test procedure in the SNOPR, but that language 
appeared instead to permit use of the ambient temperature only in 
determining the winding temperatures of sealed units, and to apply the 
conditions for use of ambient temperature also to use of direct 
measurement. Section 3.2.2 of today's final rule contains revised 
language that clearly incorporates the IEEE approach.
c. Test Set Neutrals
    Part 4.0 of the proposed test procedure set forth provisions for 
determining transformer losses, including requirements for the test 
circuits and test sets used during testing. Section 4.3.3 of the SNOPR 
required use of a ``four-wire, three-wattmeter test circuit,'' and, for 
delta-wound transformers, use of ``a neutral deriving transformer * * * 
to obtain neutral and ground.'' Commenting on this section, Howard 
Industries stated that ``[t]here are options for the design of the 
power source used to test distribution transformers,'' and recommended 
adding to this section the phrase ``unless the source is WYE 
connected.'' (Howard, No. 45 at p. 2) Although the Department does not 
agree with the change Howard recommended, this comment indicates a need 
to clarify section 4.4.3. A wye-connected power source can be used to 
test either a wye-or delta-wound transformer, and a neutral deriving 
transformer is not needed, and rarely if ever used, to obtain a neutral 
and ground. The Department has added language to today's final rule to 
make clear that the test procedure allows the use of wye- and delta-
wound power source transformers for testing, and only requires use of a 
neutral deriving transformer in conjunction with a delta-wound 
transformer.
    Today's final rule also contains a few editorial changes with 
respect to section 4.3.3 of the SNOPR test procedure. First, because 
the first sentence of that section, as proposed, concerned three-phase 
distribution transformers generally and not merely test set neutrals, 
DOE has now moved the language to section 4.3.2. Second, the remaining 
language of section 4.4.3 in the SNOPR related only to testing of 
three-phase transformers, and therefore it has been renumbered in 
today's final rule as section 4.3.2.3 (part of Three-Phase Test Sets). 
Third, to improve clarity, the term ``grounding transformer'' has 
replaced the term ``neutral deriving transformer'' throughout the test 
procedure. This is because ``grounding transformer'' is more widely 
understood in the distribution transformer community as referring to 
the type of transformer used to create a grounded neutral for a delta-
wound transformer.
d. Losses From Auxiliary Devices
    Sections 4.4.3.1 and 4.5.3.1 of the SNOPR test procedure required 
losses attributable to test instrumentation to be deducted from 
measured no-load and load losses, respectively, in determining the 
total losses of a transformer. Commenters suggested that the final rule 
also require manufacturers, in determining load losses, to exclude 
those losses attributable to auxiliary devices installed on a 
distribution transformer but which are separate from the transformer, 
such as circuit breakers, fuses, and switches, because such losses are 
not related to losses from the transformer's windings. (Howard, No. 45 
at p. 1, and No. 55 at p. 3; ERMCO, No. 49 at pp. 1-2) These commenters 
raise a valid concern, although today's final rule permits, but does 
not require, the deduction or exclusion of auxiliary device losses from 
the measured load losses.
    When a distribution transformer is equipped with auxiliary devices 
(generally specified by the customer), these devices produce some 
energy losses, albeit relatively small in comparison to the unit's 
total losses.

[[Page 24985]]

DOE anticipates that its efficiency standards would apply to 
distribution transformers without regard to whether auxiliary devices 
are installed. The standards therefore would not govern the efficiency 
of auxiliary devices, but instead would apply to the performance of the 
basic transformer (the equipment to which the auxiliary devices are 
added). Because the Department is concerned that some manufacturers may 
find it burdensome or problematic to exclude all or part of the losses 
attributable to auxiliary devices, each manufacturer will have the 
discretion to include or exclude some or all of the auxiliary-device 
losses in the determination of load losses. Although exclusion of all 
such losses would result in a more accurate efficiency rating for the 
transformer being tested, inclusion of such losses would understate the 
efficiency rating of the transformer, and not circumvent any applicable 
standard. The purchaser would be receiving a slightly more efficient 
piece of equipment than indicated by the rating. This approach is 
consistent with the Department's regulations in other portions of its 
appliance standards program, which generally allow manufacturers the 
discretion to rate their products at efficiencies lower than could be 
justified by test results. e.g., 10 CFR section 430.24. It is also 
consistent with the IEEE standards, which set forth test methods for 
distribution transformers but do not require exclusion of losses from 
accessories in measuring transformer losses.
    Today's final rule also takes this same approach for 
instrumentation losses. For the reasons just stated, the Department 
believes DOE's test procedure should permit, but not require, (as 
proposed in the SNOPR) that manufacturers deduct instrumentation losses 
from total losses in determining transformer efficiencies. This will 
allow manufacturers greater flexibility than was provided by the SNOPR 
proposal, with no detriment to the public or circumvention of any 
applicable standard.
    Therefore, section 4.5.3.1 of today's test procedure allows 
manufacturers to exclude from measured load losses those losses 
attributable to auxiliary devices, and sections 4.4.3.1 and 4.5.3.1 
allow exclusion of losses attributable to testing instruments from both 
no-load and load losses. The Department has, however, slightly modified 
the SNOPR language in proposed sections 4.4.3.1 and 4.5.3.1 that 
identified the sources of instrumentation losses. The final rule omits 
the reference to ``ammeter'' because, upon further consideration, DOE 
now realizes that no measured transformer losses are attributable to 
this instrument. The Department has also made two other similar 
modifications. The term ``wattmeter'' is replaced by ``wattmeter 
voltage circuit'' because a wattmeter experiences losses through both 
its current and voltage circuits, but only losses from the voltage 
circuit are part of measured transformer losses. The term ``instrument 
transformer'' is changed to ``voltage transformer'' because 
``instrument transformer'' refers to both current and voltage 
transformers, both of which experience losses, and it is only losses of 
the voltage transformer that are part of measured transformer losses 
and should be deducted from the total measured losses. None of these 
revisions is a departure from the substance of the SNOPR. Rather they 
improve the precision of the final rule and reduce the risk of 
misinterpretation or misapplication of the test procedure.
    With respect to how to deduct the losses from auxiliary devices 
from the measured load losses, one commenter suggested exclusion of the 
losses from auxiliary devices by removing the devices (Howard, No. 45 
at p. 1), and another suggested excluding the losses by deducting them 
from measured losses. (ERMCO, No. 49 at p. 2) Because the Department 
believes both approaches are sound, and would produce the same results, 
today's final rule allows manufacturers the flexibility of using either 
one.
e. Testing of Multiple Voltage Transformers
    Today's final rule also clarifies treatment of dual-or multiple-
voltage transformers under the Department's test procedure. 
Distribution transformers can be designed with multiple voltage ratings 
on the primary and/or secondary windings. Efficiency testing for these 
units can be problematic because, for a given transformer and kVA 
rating, DOE understands that each transformer will have two or more 
different efficiencies, i.e., one efficiency for each of its winding 
configurations. In other words, each multiple voltage transformer 
experiences different losses (and therefore different efficiencies) 
when operated at different voltages. This difference in losses is due 
to differences in current associated with the voltage configuration 
selected, and generally, the lower voltage ratings will have the higher 
losses and therefore lower efficiency ratings. The Department intends, 
however, to have just one standard level that would apply to all 
transformers in a given class, regardless of the voltage or voltages at 
which each transformer in that class is designed to operate.
    Howard Industries commented that the efficiency measurement on 
series or multiple voltage transformers should always be based on the 
highest voltage configuration. (Howard, No. 45 at p. 2; Howard, No. 55 
at p. 3) The Department is unable to accept this recommendation, 
because a transformer designed to operate at more than one nominal 
voltage would have to comply with the standard at all voltage ratings. 
Because the lowest voltage ratings would generally have the lowest 
efficiency ratings, to ensure that each multiple voltage transformer 
complies with the applicable standard at each voltage at which it 
operates, the manufacturer would have to determine the transformer's 
efficiency by testing it (or by calculating its efficiency using an 
AEDM), either at the voltage rating at which the highest losses occur--
generally the lowest voltage--or at each voltage at which the 
transformer operates. Therefore, today's final rule requires the 
manufacturer to determine the basic model's efficiency either at the 
voltage at which the highest losses occur or at each voltage at which 
the transformer is rated to operate.
f. Short-Circuiting Conductor Strap
    Section 4.5.2 of the SNOPR stated that in the test for measuring 
load losses, ``[t]he conductors used to short-circuit the windings must 
have a cross-sectional area equal to, or greater than, the 
corresponding transformer leads.'' 69 FR 45530. Howard Industries 
asserted that other methods exist for providing short-circuiting 
conductors or their equivalent, and that the test procedure should also 
permit manufacturers to use any short circuiting conductor that is ``of 
sufficient size to limit the tare watts to less than 10 percent of the 
transformer load losses.'' (Howard, No. 45 at p. 2) In industry 
parlance, ``tare watts'' are losses associated with the test set-up, 
and in this instance refer to losses in the short-circuiting conductor. 
The short-circuiting conductor losses incurred during testing are 
included in the measured load losses for the transformer being tested, 
but, as discussed above, may be deducted from the measured load losses. 
The Department's proposed requirement of a cross sectional area equal 
to, or greater than, the corresponding transformer leads is based on 
use of a simple, routine method for short-circuiting the windings by 
means of the shortest practical conductor between the terminals of the 
transformer. The Department believes this proposed

[[Page 24986]]

requirement would limit the short-circuiting conductor losses to 
approximately one to three percent of the transformer's measured load 
losses. Howard's recommended revision contemplates allowing a less 
conventional approach, and would allow losses in the short-circuiting 
strap to be as much as ten percent of the load losses.
    The Department's proposal generally follows the approach taken in 
the relevant IEEE standards. The IEEE standards are voluntary, however, 
and do not preclude manufacturers from using new, improved methods that 
do not strictly adhere to those standards. But incorporating the 
standards into DOE's test procedure would make them mandatory and limit 
manufacturer flexibility to use such new methods.
    The determination of losses in the short-circuiting strap is 
subject to errors, which will contribute to the overall error in the 
determination of transformer losses because manufacturers can deduct 
the short-circuiting losses from the measured load losses in making 
their determination of total losses. DOE is concerned that increasing 
the permissible losses, as proposed by Howard, might also increase the 
overall error--perhaps beyond acceptable limits--unless appropriate 
care is exercised to determine the higher losses of the short-
circuiting conductor. Today's rule, however, does not permit automatic 
deduction of 10 percent or any other fixed percent of losses 
denominated as occurring in the short-circuiting conductor or any other 
instrument or device. Instead, the rule provides that, in determining 
measured load losses, manufacturers may deduct only the losses 
``attributable'' to the short-circuiting conductor (as well as certain 
other instruments and devices). Thus, the rule allows deduction only of 
actual losses, i.e., losses determined with a reasonable degree of 
accuracy. Moreover, notwithstanding any increase in the amount of error 
that would be introduced by adoption of Howard's proposal in today's 
rule, the overall limit on the range of error for measurement of power 
losses remains at  3 percent, as proposed in the SNOPR. 
Thus, adoption of the proposal would not have a significant effect on 
overall results determined under the test procedure.
    For these reasons, today's rule allows manufacturers to use 
alternatives to the method specified in proposed section 4.5.2(b) for 
providing short-circuiting conductors, so long as such alternatives do 
not result in losses that are 10 percent or more of the total load 
losses. The language to implement this approach, however, varies 
slightly from the language proposed by Howard Industries. Howard's 
proposed language could be construed as permitting losses as great as 
10 percent, even if a manufacturer uses the method prescribed in the 
SNOPR. The Department sees no reason to allow that, and believes losses 
of that magnitude should be permitted only if a manufacturer uses 
alternative methods.
g. Revisions Suggested by NEMA in TP 2-2005
    As stated above, NEMA prepared a revised version of NEMA TP 2-1998 
and submitted it to the Department for review. (NEMA, No. 60 at p. 1) 
The Department compared this document, designated by NEMA as TP 2-2005 
(NEMA, No. 60 Attachment 1), with the rule language proposed in the 
SNOPR to identify all changes to the SNOPR's methods, procedures and 
language. For the purposes of this final rule, DOE is treating the 
differences that it identified as written comments submitted by NEMA on 
the SNOPR. The following discussion examines the significant 
differences that DOE has not addressed elsewhere in this notice.
    NEMA's TP 2-2005 contains a definition for ``tolerances on measured 
losses'' which was not provided in the SNOPR and which reads: 
``Measured values of electrical power, voltages, currents, resistances, 
and temperature are used in the calculations of reported data. To 
ensure sufficient accuracy in the measured and calculated data, the 
test system accuracy for each measurement shall fall within the limits 
specified in Table 4.'' (NEMA, No. 60 Attachment 1, p. 8) The 
Department has not added this definition to the list of terms it is 
defining in the final rule because it believes such a definition would 
not further clarify or add substance to the rule. Except for its range 
for frequency measurement accuracy, Table 2-1 \7\ of TP 2-2005 sets 
forth the same accuracy ranges as are contained in Table 2.1 in the 
SNOPR. Moreover, section 2.0 of DOE's test procedure states that 
``measurement error will be limited to the values shown in Table 2.1.'' 
69 FR 45524. The Department believes these accuracy requirements for 
the measurement of losses are sufficient and clear, and a definition of 
``tolerances on measured losses'' is therefore unnecessary.
---------------------------------------------------------------------------

    \7\ In the March 2005 draft of NEMA TP 2-200X, Table 4, 
Measurement Accuracy Requirements, was the correct citation. In 
preparing the final draft, Table 4 was re-labeled as Table 2-1, and 
all the values remained the same. The language on page 8 of TP 2-
2005 makes references to Table 4; however, this appears to be a 
typographical error as there is no Table 4 in TP 2-2005.
---------------------------------------------------------------------------

    As just indicated, Table 2-1 of NEMA TP 2-2005 contains an accuracy 
range for frequency measurement of  0.5 percent. (NEMA, No. 
60 Attachment 1, p. 9) The Department has decided not to add such a 
provision to Table 2.1 of today's final rule, however, for the 
following reasons. First, neither TP 2-1998 nor the widely-used IEEE 
test methods, which DOE used to develop today's test procedure, contain 
an accuracy range for frequency measurement. Secondly, except in 
unusual cases, it is not needed. When power is supplied from the 
utility grid, frequency is very accurate and there is no need to 
prescribe a frequency accuracy or require manufacturers to take steps 
to assure accuracy. The Department would only require manufacturers to 
assure accuracy when the power supply is not synchronized with an 
electric utility grid, and this is addressed in sections 4.4.2 and 
4.5.2 of the SNOPR. Thus, the Department has not added a frequency 
accuracy range to Table 2.1.
    Compared to the SNOPR, NEMA's TP 2-2005 contains slightly different 
and longer definitions of ``load'' and ``no-load'' loss. The SNOPR 
reads that ``[l]oad loss means, for a distribution transformer, those 
losses incident to a specified load carried by the transformer, 
including losses in the windings as well as stray losses in the 
conducting parts of the transformer. It does not include no-load 
losses.'' NEMA's revised TP 2-2005 reads ``load loss: The load losses 
of a transformer are those losses incident to the carrying of a 
specified load by the transformer. Load losses include I\2\R loss in 
the windings due to load and eddy currents; stray losses due to leakage 
fluxes in the windings, core clamps, and other parts, and the loss due 
to circulating currents (if any) in parallel windings, or in parallel 
winding strands.'' (NEMA, No. 60 Attachment 1, p. 4) The Department has 
not modified its proposed definition of ``load loss,'' except by 
deleting the last sentence as NEMA did in TP 2-2005. The Department 
recognizes that inclusion of this last sentence would make the 
definition inaccurate, because an insignificant amount of no-load loss 
is included in the measurement of load loss. Also, retention of this 
sentence might incorrectly imply that manufacturers should subtract 
this extremely small amount of no-load loss from load-loss 
measurements, to determine load loss.
    However, DOE believes that the remainder of its proposed definition 
of ``load loss'' is clear and not susceptible

[[Page 24987]]

of misunderstanding, and its brevity is preferable to the approach in 
TP 2-2005. The description of the various components of ``load loss'' 
in the NEMA definition helps explain the causes of load loss, but 
neither alters nor clarifies the definition or the requirements that 
the definition delineates. Such explanation generally is not included 
in rule language.
    Concerning the definition of ``no-load loss,'' the Department's 
SNOPR reads: ``[n]o-load loss means those losses that are incident to 
the excitation of the transformer.'' NEMA's revised TP 2 definition 
reads: ``no-load (excitation) loss: No-load (excitation) losses are 
those losses that are incident to the excitation of the transformer. 
No-load (excitation) losses include core loss, dielectric loss, 
conductor loss in the winding due to excitation current, and conductor 
loss due to circulating current in parallel windings. These losses 
change with the excitation voltage.'' Again, the Department considers 
the SNOPR definition to be clear and complete for the purposes of this 
test procedure. As with its suggested definition of ``load loss,'' 
NEMA's definition of ``no-load loss'' adds information, but its list of 
components is explanatory rather than substantive, and DOE has concerns 
similar to those discussed for the ``load loss'' definition. For these 
reasons, the Department is not modifying, except as indicated, either 
the ``no-load loss'' or the ``load loss'' definitions.
    NEMA TP 2-2005 introduces a definition of ambient temperature. 
(NEMA, No. 60 Attachment 1, p. 3) This definition appears to be derived 
from the American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE) Terminology of Heating, Ventilation, 
Air Conditioning, & Refrigeration (Second Edition) and has several 
elements that apply to types of transformers that are not distribution 
transformers. Therefore, it is not applicable to the Department's test 
procedure. Moreover, DOE believes that, in the context of today's final 
rule, ambient temperature clearly refers to the room temperature in the 
location where the measurements are being taken, as DOE intends. For 
these reasons, the Department believes a definition of ambient 
temperature is unnecessary in today's rule.
    Finally, NEMA TP 2-2005 contains a number of editorial changes to 
the language in the SNOPR's test methods. The Department has 
incorporated several of these, such as edits in the first paragraph of 
proposed section 6.1, in today's final rule.
h. Language Corrections as to Conversion of the Resistance Measurement 
to the Reference Temperature and Conducting the No-Load Loss Test
    Section 3.5 of DOE's proposed test procedure provided an equation 
for correcting measured resistance to the resistance at the reference 
temperature. 69 FR 45527. One of the terms of this equation, 
Tk, consists of a temperature level for copper windings, 
another for aluminum windings, and a third level ``[w]here copper and 
aluminum windings are employed in the same transformer.'' However, a 
separate resistance measurement is performed for each winding of a 
distribution transformer. Section 3.5 provides for adjustment of each 
such measurement, and each winding will be either copper or aluminum, 
but not both. Therefore, the equation for adjusting the measured 
resistance need not, and should not, include a temperature level that 
contemplates the use of the two metals together, and in today's final 
rule, the Department has deleted from section 3.5 the language that 
includes such a temperature level.
    Section 4.4.2 of the proposed test procedure concerns testing for 
no-load losses. Proposed paragraph (b) of that section directed the 
tester to ``[e]nergize not less than 25 percent'' of either the high 
voltage or low voltage winding. 69 FR45530. The Department drew the 25 
percent figure from section 8.2.3 of IEEE C57.12.90-2001 and C57.12.91-
2001, which recommend energizing 100 percent of the winding in 
conducting this test, but allow as low as 25 percent. The IEEE 
standards allow the 25 percent because they apply not only to 
distribution transformers but also to power transformers. Power 
transformers may require much higher voltages than are available in the 
power sources used in performing the no-load test. Distribution 
transformers, however, require much lower voltages, which can be 
accommodated by the available power sources. Moreover, distribution 
transformers rarely have a 25-percent voltage tap that would permit 
energizing a winding at 25 percent of its rated voltage, and DOE 
understands that instead, in testing distribution transformers for no-
load losses, windings are energized to 100 percent of rated voltage. 
Hence, DOE has deleted from today's final rule the provision allowing 
testers to energize 25 percent or more of a winding.
    Proposed paragraph (c) of section 4.4.2 required certain conditions 
with respect to voltage during the no-load loss test, ``unless 
otherwise specified.'' 69 FR 45530. Once again, DOE drew the quoted 
language from IEEE standards, where it is included to accommodate 
testing as to characteristics other than efficiency, in situations 
where a transformer includes special features requested by a customer. 
Because this language has no application to efficiency testing, and 
such testing must always be conducted under the conditions specified in 
proposed paragraph (b), section 4.4.2(c) of today's final rule does not 
include this language.

D. Basic Model

1. General Discussion
    Under the Department's energy conservation program, DOE has applied 
the ``basic model'' concept to alleviate burden on manufacturers, by 
reducing the amount of testing they must do to rate the efficiencies of 
their products. DOE's intent is that a manufacturer would treat each 
group of its models that have essentially identical energy consumption 
characteristics as a ``basic model,'' such that the manufacturer would 
derive the efficiency rating for all models in the group from testing 
sample units of these models. All of the models in the group would 
comprise the ``basic model,'' and they would all have the same 
efficiency rating. The proposed definition of basic model for 
distribution transformers implements this approach by permitting 
manufacturers to aggregate models that have the same energy consumption 
characteristics, but not models with different characteristics. 
Components of similar design can be substituted in a basic model 
without requiring additional testing if the represented measures of 
energy consumption continue to satisfy applicable provisions for 
sampling and testing.
2. Definition of a Basic Model
    In the SNOPR, the Department proposed a definition of ``basic 
model'' for distribution transformers that included essentially the 
same criteria as those contained in the definition proposed in the 1998 
proposed rule, plus a requirement that the transformers included in the 
basic model ``not have any differentiating electrical, physical or 
functional features that affect energy consumption.'' DOE made several 
other modifications to the definition, and described these changes in 
the SNOPR. 69 FR 45512-13.
    NEMA commented that the SNOPR definition of ``basic model'' was too 
vague and needed clarification. (Public Meeting Transcript, No. 42.11 
at pp. 22-23) Specifically NEMA was concerned

[[Page 24988]]

that the phrase added to the end of the basic model definition ``and do 
not have any differentiating electrical, physical, or functional 
features that affect energy consumption'' is unclear. (NEMA, No. 39 at 
p. 2) DOE believes that these general criteria for the creation of 
basic models are needed to allow manufacturers the flexibility to 
create basic model groupings that reflect product features that affect 
energy consumption. To address NEMA's concern, DOE is modifying the 
definition slightly to provide that voltage and basic impulse 
insulation level (BIL) rating are both examples of differentiating 
electrical features that would cause transformer models to be different 
basic models. DOE stated in the preamble of the SNOPR that each of 
these features would be a differentiating electrical characteristic, 
but the proposed definition itself did not include these examples.
    Additionally, NEMA noted it would prefer that the rule contain a 
table of basic models (NEMA, No. 39 at p. 2) or a tighter definition. 
(Public Meeting Transcript, No. 42.11 at p. 37) DOE believes that 
creation of a table of basic models would be impractical for several 
reasons. First, there are literally thousands of possible designs for 
any one kVA rating and combination of core steel and winding materials. 
Second, for DOE to attempt to identify both the energy consumption 
profile of each such combination of transformer features, as well as 
the combinations that have common profiles, would be an enormous 
undertaking. Third, to the extent that any significant number of these 
possible transformer variations is not produced, either now or in the 
future, effort may be wasted. And fourth, DOE believes that neither it 
nor industry can accurately anticipate all future design variations of 
distribution transformers. A table or other rigid definition, 
therefore, would (1) fail to provide for future designs, and/or (2) 
conflict with the rationale for using the ``basic model'' construct, 
and (3) force future designs to be grouped with models that do not 
share their energy consumption characteristics. As this last point 
indicates, NEMA's concern that the part of the definition quoted above 
could allow additional basic models at a later date is misplaced. To 
the extent that the definition would allow creation of additional basic 
models that subsume models with new energy consumption characteristics, 
this indicates the definition is sound rather than in need of 
alteration.
    DOE recognizes that, given the large number of variations in 
distribution transformer design, many manufacturers produce numerous 
basic models. The Department is aware, however, of no reasonable way to 
aggregate models with different energy consumption characteristics, for 
purposes of testing, that would produce an accurate efficiency rating 
for each model included in the grouping. Today's final rule, however, 
will allow manufacturers to rate the efficiency of many of their 
transformers based on calculations instead of testing, by using 
alternative efficiency determination methods. This should substantially 
alleviate any potential testing burden created by a manufacturer's 
producing large numbers of basic models.
    In summary, DOE will slightly modify the proposed definition of 
``basic model'' to explicitly provide that (1) voltage and BIL ratings 
are examples of differentiating electrical features that would cause 
transformer models to be different basic models, and (2) each basic 
model would comprise a group of models of distribution transformers. 
Otherwise, the proposed definition is sound because its specific 
elements and general criteria combine to allow the grouping of models 
with similar energy consumption characteristics without allowing models 
with different characteristics to be included in the same group.

E. Manufacturer's Determination of Efficiency

1. General Discussion
    During this rulemaking, NEMA advocated DOE adoption of the sampling 
plan for compliance testing in NEMA TP 2-1998, which would allow 
manufacturers to demonstrate the compliance of aggregations of basic 
models, and the Department presented and solicited comment on several 
alternative approaches for demonstrating such aggregate compliance. For 
the reasons discussed in the SNOPR, the Department chose not to propose 
adoption of either the NEMA TP 2-1998 sampling plan or an alternative 
approach allowing aggregation. 69 FR 45513-15.
    Instead, the Department has adopted both a sampling plan for 
compliance testing, and provisions allowing use of alternative methods 
(other than actual testing), for manufacturers to use to determine the 
efficiency of individual basic models of distribution transformers. As 
proposed in the SNOPR, today's rule requires each manufacturer to 
determine the efficiency of each of its basic models on a one-time 
basis by testing, at least five with compliance testing, and by rating 
each of the remaining basic models either by testing it, or, under the 
conditions set forth in the rule, by calculating the basic model's 
efficiency using an alternative efficiency determination method (AEDM). 
Where the manufacturer uses an AEDM for a basic model, it would not 
test units of the basic model to determine its efficiency for purposes 
of establishing compliance with DOE requirements.
2. Sampling Plan
    The Department designed the sampling plan in today's final rule to 
provide a high probability that manufacturers would find each basic 
model to be in compliance with the efficiency level at which it is 
manufactured, but without creating a significant probability that 
models would be found to meet levels higher than those at which they 
are manufactured. The latter--``false positives''--would in effect 
create a regulatory loophole, by allowing transformer models 
manufactured at efficiency levels below applicable standards to be 
rated as compliant with those standards. The Department's goal for 
distribution transformers is to have about a 97.5 percent probability 
that tests on sample units of a basic model would verify or support an 
efficiency rating for the model that is equal to or less than the 
average efficiency of all units of that model manufactured. Stated 
alternatively, a basic model that is manufactured at or above its rated 
efficiency would have a probability of not less than 97.5 percent of 
passing the compliance demonstration test--i.e., being found in 
compliance with its rated value--based on test results using any sample 
size.
    To accomplish this goal, DOE incorporated into its proposed 
sampling plan a one-sided statistical z-test, with a 97.5 percent 
confidence limit for average efficiency or power loss, which 
manufacturers would apply to the test results derived from testing 
sample units of a basic model. The 97.5 percent confidence limit in the 
one-sided z-test corresponds to 2[sigma]/[radic]n, where [sigma] 
represents the standard deviation of units of distribution 
transformers, and n is the number of units, including one, in the 
sample. Thus, for example, if a manufacturer tested a sample of only 
one unit of a basic model, and its measured power loss did not exceed 
the rated power loss of the basic model by more than the amount 
representing two standard deviations, the test would confirm the 
validity of the rated efficiency. By way of further example, if the 
manufacturer tested a sample of more than one unit, the numerical value 
for losses corresponding to the 97.5

[[Page 24989]]

percent confidence limit would decrease, and the precision of the 
determination of the average losses for the basic model would increase.
    In developing the SNOPR, DOE had information both to support a 
standard deviation (SD) for distribution transformers of 2.7 percent 
and to support one of 4 percent. Since the information in support of 
the 2.7 percent level was slightly stronger, DOE based the confidence 
limit (or ``tolerance'') \8\ in the SNOPR sampling plan on the SD of 
2.7 percent. 69 FR 45515. Two SDs of 2.7 percent correspond to a 
tolerance for the average efficiency of the sample of units tested of 
5/[radic]n percent. (Most commenters who commented on the sampling plan 
tolerance level addressed it as a straight numerical amount, although 
in actuality the proposed tolerance is a tolerance that depends on the 
size of the sample of units tested, and is 5/[radic]n percent. The 
commenters may have used straight numerical amounts because application 
of the expression 5/[radic]n percent to a sample size of one would 
always result in a flat five-percent tolerance.)
---------------------------------------------------------------------------

    \8\ The precise statistics term ``confidence limit'' is 
frequently replaced in engineering applications by a more general 
term ``tolerance.'' In the preceding discussion, DOE used the 
precise term to explain the basis of the tolerance in the SNOPR's 
proposed sampling plan for compliance testing. The Department will 
use the term ``tolerance'' in the discussion that follows, 
particularly because all of those who commented on this issue used 
this term.
---------------------------------------------------------------------------

    The Department received several comments stating that its proposed 
tolerance was too stringent, and should be relaxed. NEMA notes that the 
Department's equation relating the average efficiency of the sample and 
the represented efficiency assumes a tighter performance probability 
distribution function than is achievable in practice, particularly for 
small manufacturers. (NEMA, No. 47 at p. 3; NEMA, No. 51 at p. 3)
    Four commenters requested that the tolerance for individual units 
be relaxed from the SNOPR proposal of five percent to eight percent. 
(ERMCO, No. 43 at p. 2; FPT, No. 44 at p. 6; Howard, No. 45 at p. 2; 
EMS, No. 57 at p. 3) Federal Pacific commented that use of a five-
percent tolerance is too stringent given the variability of transformer 
losses, particularly the variability of no-load losses. (FPT, No. 44 at 
p. 6) EMS and ERMCO recommend that the tolerance should be eight 
percent to be consistent with IEEE/ANSI C57.12.00 and NEMA TP 2. (EMS, 
No. 57 at p. 3; ERMCO, No. 43 at p. 2) Howard Industries also 
recommended that the minimum acceptable efficiency level calculation be 
based on an eight-percent tolerance on total loss. (Howard, No. 45 at 
p. 2)
    Four commenters advocated a 12-percent tolerance, which would 
equate to three SDs of 4 percent. (Cooper, No. 46 at pp. 1-2; HVOLT, 
No. 53 at pp. 1-2; PQI, No. 56 at pp. 1-2; NEMA, No. 59 at p. 1, NEMA, 
No. 60, Attachment 1 at p. 34) This tolerance level would increase the 
compliance demonstration probability to 99.9 percent, but would also 
allow for a significant probability of false positives. For example, a 
basic model designed with losses 2 percent above its rated value would 
have a 99.4-percent probability of being found to have an efficiency at 
or above its rated level if the sample size is one, and would have a 
97-percent probability of being found to have such an efficiency if the 
sample size is five. In addition, a 12-percent tolerance would be 
inconsistent with the much smaller tolerance, for rejection of single 
units, in existing IEEE standards. For these reasons, the Department is 
not incorporating the 12-percent tolerance level into its sampling 
plan.
    Three of the commenters advocating the 12-percent tolerance for 
compliance testing based their position in part on the assertion that 
DOE's rule for electric motors allows a 20-percent ``test tolerance 
band.'' (Cooper, No. 46 at p. 2; HVOLT, No. 53 at p. 2; PQI, No. 56 at 
p. 2) The tolerance to which they refer in the electric motors rule is 
not applicable to distribution transformers for two reasons. First, the 
20-percent tolerance in the motors rule applies during testing that 
occurs in enforcement proceedings. The rule uses this tolerance to 
determine the adequacy of the size of the test sample used in the 
proceeding, following testing of the initial sample, and determination 
of the sample's mean, standard deviation, and standard error. This 20-
percent tolerance has no relevance to compliance testing. Second, 
application of a particular tolerance with respect to efficiency and 
losses for electric motors does not indicate the appropriate tolerance 
for distribution transformers. Induction motors have a similarity to 
transformers in that their stator and rotor windings are akin somewhat 
to the primary and secondary windings of a transformer. However, at 
that point the similarity ends. A transformer has no moving parts in 
normal operation whereas a motor's main feature is the spinning of the 
rotor, a mechanical process which in itself absorbs considerable 
energy. Thus, motors, in addition to having electrical power losses, 
also have mechanical losses. Consequently the comparison of motors and 
transformers when discussing tolerances used in determining efficiency 
is inappropriate.
    Based on the information provided in comments, DOE now believes 
that 4 percent is the better SD to use, and that the available 
information supporting the 4 percent figure outweighs that supporting 
the 2.7-percent SD. Two SDs at 4 percent equates to an eight-percent 
single unit tolerance, and results in a tolerance for the average 
efficiency of the sample of units tested of 8/[radic]n percent. 
Increasing the tolerance from 5/[radic]n percent to 8/[radic]n percent 
increases the probability of demonstrating compliance of a product 
manufactured at the applicable standard level from about 89 percent to 
about 98 percent, without introducing a significant probability that a 
product manufactured below the standard level would be found in 
compliance. This assumes that the variability of units of the basic 
model being tested have a standard deviation of 4 percent. The 
probability of a significant false positive--finding a model in 
compliance with its rated efficiency where on average the units of that 
model as manufactured actually experience a power loss 2-percent larger 
than the rated loss--is approximately 93 percent for a sample of one 
unit and 81 percent for a sample of five units. Both probabilities, 
especially the second one, are sufficiently low that a manufacturer 
would not risk producing a product with power losses 2 percent or more 
above the losses at which it seeks to rate the product. Thus, today's 
final rule increases the tolerance from 5/[radic]n percent to 8/
[radic]n percent.
    Several manufacturers submitted comments asking that DOE confirm 
that they have the option of testing all transformers of a basic model 
or some basic models. (Public Meeting Transcript, No. 42.11 at p. 22; 
NEMA, No. 39 at p. 2) One stakeholder requested clarification that if 
it chooses to test 100 percent of its production, it would not have to 
use the sampling plan or an AEDM (alternative efficiency determination 
method). (Public Meeting Transcript, No. 42.11 at p. 65) NEMA also 
requested clarification on the number of samples that would have to be 
tested if the sample size is small. (Public Meeting Transcript, No. 
42.11 at p. 67)
    As indicated above, once efficiency standards for distribution 
transformers have gone into effect, today's rule will require each 
manufacturer to rate the efficiency of each of its basic models on a 
one-time basis. The rating would enable the manufacturer to establish 
that the basic model complies with the applicable standard, and provide 
the basis for any energy representations

[[Page 24990]]

(e.g., labeling and certification) required by DOE. 69 FR 45514. The 
Department intended in its SNOPR proposal, and wishes to confirm with 
respect to today's rule, that where a manufacturer arrives at this 
rating through testing, rather than use of an AEDM, the sampling plan 
would permit the manufacturer to test 100 percent of the units 
available for testing. The language of section 431.194(b)(2) of the 
final rule has been modified to make this clear. Thus, where 
manufacturers have on hand more than five units of a basic model at the 
time they do compliance testing to rate the basic model, or produce 
more than five over a six-month period, they would have the discretion 
to rate the basic model based on testing either all of the units or a 
sample of at least five units. In addition, the final rule clearly 
requires compliance testing of 100 percent of the units for basic 
models for which a manufacturer produces five or fewer units during a 
six-month period.
    None of the provisions in today's rule would prevent a manufacturer 
from doing continuous testing of 100 percent of the units it produces 
in order to meet contractual obligations to report to its customers the 
losses, efficiency or other energy consumption characteristics of each 
individual unit it sells to them. Nor does the Department anticipate 
that provisions it may adopt, for assuring compliance with energy 
conservation standards and for manufacturer representations (e.g., 
labeling) as to efficiency, would prevent manufacturers from testing 
all of their units in order to meet such obligations.
3. Alternative Efficiency Determination Method (AEDM)
    Under the proposed rule, a manufacturer would have to validate each 
AEDM it uses based on test data for at least five basic models, derived 
by testing at least five units of each of these basic models. 69 FR 
45522. Taken together, these provisions would require testing of at 
least 25 units to validate an AEDM. Howard Industries commented that 
five basic models is too small a sample to adequately represent all the 
different kVA/voltages/BIL requirements when validating an AEDM and 
recommended that DOE require 75 models to be tested to validate an 
AEDM. (Howard, No. 45 at p. 3, and No. 55 at p. 3) Howard also asserted 
that five basic models was too low a number to verify that the AEDM 
would accurately predict the efficiency of all liquid-immersed 
transformers. It stated that transformers vary considerably, with a 
large number of design options. (Howard, No. 58 at p. 1) In addition to 
containing the validation requirement, however, the final rule (in 
section 431.197(a)(2)(i)) also precludes a manufacturer from applying 
an AEDM to a basic model unless ``the AEDM has been derived from a 
mathematical model that represents the electrical characteristics of 
that basic model.'' Thus, apart from any testing to validate the 
accuracy of an AEDM, this language will require each AEDM to represent 
any unique or custom-designed electrical characteristics of any basic 
model to which it applies. DOE believes that this provision 
satisfactorily addresses Howard's concern that DOE require AEDMs to 
reflect the particular characteristics of the transformers to which 
they apply.
    The Department believes that to require each AEDM to be validated 
based on testing of 75 basic models, or some other number larger than 
five, would create undue burden. The foregoing is particularly true 
because DOE understands that manufacturers use design models and 
software to design their distribution transformers, and DOE believes 
that most AEDMs would be derived from, or consist of, such models and 
software. Since these design tools would have validity independent of 
the AEDM substantiation required by DOE regulations, extensive testing 
to substantiate the validity of AEDMs appears to be unnecessary.
    Section 432.12(a)(2)(iii) of the proposed rule restricted the use 
of each AEDM to one of the following groups of distribution 
transformers: low-voltage dry-type transformers, medium-voltage dry-
type transformers, and liquid-immersed transformers. 69 FR 45522. Upon 
further review, the Department believes that this provision is too 
restrictive, and that manufacturers should be permitted to use a single 
AEDM for distribution transformers in two or all three of these groups, 
so long as the manufacturer validates the AEDM separately for each 
group. The Department is aware of no reason why it should limit use of 
each AEDM to transformers in one of these groups, if the AEDM can 
validly predict the efficiency for transformers in more than one group. 
Accordingly, today's final rule allows a single AEDM to apply to two or 
all three of these groupings. See 10 CFR section 431.197(a)(2) of the 
rule. The rule also requires that the manufacturer validate each AEDM 
separately for each group--i.e., low-voltage dry-type, medium-voltage 
dry-type, and liquid-immersed--for which it uses the AEDM, based on 
test data for five basic models from such group. 10 CFR section 
431.197(a)(2)(iii) of the rule. Thus to substantiate a single global 
AEDM that would apply to the entire range of distribution transformers 
(all three groups), a manufacturer would have to test not fewer than 15 
basic models (a total of at least 75 units), and it would have to test 
at least 10 basic models (a total of at least 50 units) to substantiate 
an AEDM that would apply to two groups. DOE believes this amount of 
testing to validate the AEDM is sufficient.
    The SNOPR also included a requirement that manufacturers 
``periodically'' verify each AEDM that they use. 69 FR 45523. Howard 
Industries recommended that the Department change ``periodically'' to 
``annually.'' (Howard, No. 45 at p. 3, and No. 55 at p. 3) The 
Department considered this proposal, but decided that annual 
verification of an AEDM, which could include testing, could be unduly 
burdensome on manufacturers. The Department has also decided, however, 
largely because of the particular circumstances of the distribution 
transformer industry, to eliminate the periodic verification 
requirement from today's final rule. Many distribution transformer 
manufacturers already engage in continuous testing--sometimes by 
testing 100 percent of their units--to assure that the actual 
performance, including efficiency, of their products conforms to the 
manufacturer's design software and representations to customers. In 
addition, other provisions of today's final rule authorize DOE to 
obtain information from manufacturers concerning their use of AEDMs, 
and to require a manufacturer to do sample testing or take other steps. 
Thus, DOE now believes that mandatory, periodic, subsequent 
verification of AEDMs for distribution transformers is unwarranted.

F. Enforcement Procedures

    The SNOPR included proposed enforcement procedures, including a 
sampling plan and other provisions for enforcement testing. 69 FR 
45415-17, 45523-23, 45533-34. The Department based the proposed 
procedures on enforcement provisions in 10 CFR Part 430, which apply 
when DOE examines whether a basic model of a covered product complies 
with efficiency requirements set forth in those parts. The SNOPR's 
enforcement sampling plan was based on the plan in Part 430, but was 
developed specifically for distribution transformers. It allows testing 
of small sample sizes and applies only to energy efficiency testing, 
whereas the Part 430 plan contemplates

[[Page 24991]]

larger sample sizes and covers energy use testing.
    NEMA requested clarification on when the process of enforcement 
commences. (Public Meeting Transcript, No. 42.11 at p. 73) The 
Department initiates the enforcement process when it receives 
information, either from a third party or other source, indicating that 
a manufacturer's units may not be in compliance with the national 
standard. Initially, DOE seeks to meet with the manufacturer and review 
its underlying test data as to the models in question. DOE would 
commence enforcement testing procedures if these steps do not resolve 
identified compliance issues.
    The Department also received comments relating to enforcement as to 
stock units and imported units. Cooper sought clarification on 
application of efficiency standards to units in stock when standards 
take effect, and to foreign manufacturers. (Cooper, No. 46 at p. 2) 
Traditionally, new DOE standards for a product have applied to units 
manufactured after a certain date, or, in the case of foreign-
manufactured units, imported after that date. See, e.g., 42 U.S.C. 
6291, 6295, 6311 and 6313. The Department anticipates that this will 
also be the case for distribution transformers. Therefore, the 
efficiency levels would not apply to units in a domestic manufacturer's 
stock prior to the date standards become applicable, or to units 
imported prior to that date. In all other respects, DOE anticipates 
that the same requirements and enforcement provisions that apply to 
domestic units will also apply to imported units. In addition, however, 
imported units are subject to the provisions of 42 U.S.C. 6301 of EPCA, 
concerning importation of products subject to EPCA requirements.
    HVOLT commented that the Department should require that the 
efficiency of any foreign-built transformer be verified by a third 
party before it can be sold in the U.S. (HVOLT, No. 53 at p. 3) The 
Department believes that this issue is outside the scope of this 
rulemaking. Today's final rule does not address the DOE administrative 
framework for manufacturers to follow to demonstrate compliance with 
distribution transformer energy conservation standards. The Department 
will likely address such requirements in conjunction with the standards 
rulemaking.
    The SNOPR enforcement sampling plan contained several calculation 
equations. 69 FR 45533. Federal Pacific requested further explanation 
and examples of the enforcement calculations. (FPT, No. 44 at p. 6) As 
explained in the SNOPR, the statistical methods used in those 
calculations were based on well-established statistical methods for 
obtaining a confidence interval on a mean. 69 FR 45516. Hence, the 
Department believes these calculations can be understood by any 
statistician. In addition, a complete explanation is set forth in NIST 
Technical Note 1456, Operating Characteristics of the Proposed Sampling 
Plans for Testing Distribution Transformers, May 2004, which has been 
placed in the docket for this rulemaking and is publicly available at 
http://www.eere.energy.gov/buildings/appliance_standards/commercial/dist_transformers.html. On the other hand, it would be very burdensome 
for DOE to develop and include in this notice a detailed explanation, 
in layman's terms, of the statistics and operation of these equations. 
Furthermore, these equations will be used by DOE, and would not be 
applied by manufacturers. For these reasons, the Department has 
concluded that the type of explanation Federal Pacific requests is 
unwarranted, and would add little useful information to the record of 
this rulemaking.

III. Procedural Requirements

A. Review Under Executive Order 12866

    The Office of Information and Regulatory Affairs of the Office of 
Management and Budget (OMB) has determined that today's regulatory 
action is not a ``significant regulatory action'' under Executive Order 
12866, ``Regulatory Planning and Review,'' 58 FR 51735 (October 4, 
1993). Accordingly, this action was not subject to review under the 
Executive Order.

B. Review Under the Regulatory Flexibility Act of 1980

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of an initial regulatory flexibility analysis for any rule 
that by law must be proposed for public comment, unless the agency 
certifies that the rule, if promulgated, will not have a significant 
economic impact on a substantial number of small entities. As required 
by Executive Order 13272, Proper Consideration of Small Entities in 
Agency Rulemaking, 67 FR 53461 (August 16, 2002), DOE published 
procedures and policies on February 19, 2003, to ensure that the 
potential impacts of its rules on small entities are properly 
considered during the rulemaking process. 68 FR 7990. The Department 
has made its procedures and policies available on the Office of General 
Counsel's Web site: http://www.gc.doe.gov.
    The Department reviewed today's final rule under the provisions of 
the Regulatory Flexibility Act and the procedures and policies 
published on February 19, 2003, and certified in the SNOPR that the 
proposed rule would not impose a significant economic impact on a 
substantial number of small entities. 69 FR 45517. As indicated in 
section I-A above, when it issued the SNOPR DOE was concurrently 
pursuing a rulemaking to develop energy conservation standards for low-
voltage dry type, medium-voltage dry type and liquid immersed 
distribution transformers. The Department explained in the SNOPR that, 
unless and until DOE adoption of such standards, no entities, small or 
large, would be required to comply with today's final rule. 69 FR 
45517. Once the Department adopted standards, however, the rule would 
become binding on, and could have an economic impact on, small entities 
which manufacture the distribution transformers subject to the 
standards. But the nature and extent of such impact, if any, could not 
be assessed until the Department has promulgated the standards. The 
Department stated in the SNOPR that, in light of these circumstances, 
at an appropriate point in conjunction with the standards rulemaking, 
it will conduct further review under the Regulatory Flexibility Act. 
The Department received no comments on this issue in response to the 
SNOPR.
    For medium-voltage dry-type and liquid immersed distribution 
transformers, DOE is continuing to pursue its standards-development 
rulemaking and the circumstances described in the SNOPR still exist. 
Therefore, after considering the potential impact of this final rule on 
small entities that manufacture these transformers, DOE affirms the 
certification that this rule will not have a significant economic 
impact on a substantial number of these small entities.
    Low-voltage dry-type distribution transformers, however, are no 
longer included in DOE's rulemaking on energy conservation standards 
for distribution transformers. Instead, EPCA, as amended in EPACT 
20005, now specifies minimum standards for all such transformers 
manufactured after January 1, 2007, 42 U.S.C. 6295(y), and the 
Department has incorporated those standards into its regulations. 10 
CFR section 431.196. Because today's rule will apply to all 
distribution transformers that become subject to standards, as of 
January 1, 2007, the rule

[[Page 24992]]

would become binding on all manufacturers, small and large, of low-
voltage dry-type distribution transformers. Consequently, under the 
Regulatory Flexibility Act, the Department must assess the economic 
impact of this rule on small manufacturers of these transformers.
    Small businesses, as defined by the Small Business Administration 
(SBA) for the distribution transformer manufacturing industry, are 
manufacturing enterprises with 750 employees or fewer. The Department 
estimates that, of a total of approximately 55 manufacturers of low-
voltage dry-type distribution transformers, about 45 are small 
businesses under the SBA definition. In today's rule, the enforcement 
provisions and the methods manufacturers must use to rate its products 
could potentially impose burdens on these small manufacturers. But DOE 
has examined these aspects of the rule and determined that they will 
not have a significant economic impact on a substantial number of small 
manufacturers of low-voltage dry-type distribution transformers.
    As to the enforcement provisions, they require DOE to first attempt 
to resolve a transformer's possible non-compliance with EPCA 
requirements by reviewing available information and meeting with the 
manufacturer. Then, if necessary, DOE must test sample units of the 
allegedly non-complying basic model(s) to determine whether they 
comply. See Section 431.198 of the attached rule. Only provisions that 
come into play once DOE invokes testing--specifically, manufacturers 
must provide and ship sample units to DOE and must retain all units in 
the batch sample until a final determination of compliance or non-
compliance, and manufacturers may conduct additional testing at their 
own expense if the DOE testing indicates non-compliance--could impose a 
significant burden on manufacturers.
    None of the enforcement provisions imposes on-going duties on 
manufacturers. They apply only when an issue of compliance is raised, 
which at this point is speculative. Indeed, even when they are invoked 
as to a particular manufacturer, they will only apply to the specific 
basic model(s) at issue. Moreover, these types of enforcement 
provisions have been in place for DOE's program for appliance energy 
conservation standards for more than 15 years, and the Department has 
commenced the process at most two or three times a year. In every 
instance it has resolved the matter without proceeding to enforcement 
testing, the only part of the process that could impose a significant 
burden on manufacturers. For all of these reasons the Department 
concludes that the enforcement provisions in today's rule will not have 
a significant impact on a substantial number of entities, whether small 
or large.
    As to the methods for manufacturers to rate the efficiencies of 
low-voltage dry-type distribution transformers, DOE notes initially 
that requirements for testing and rating these transformers are already 
implicit in EPCA. Specifically, to comply with EPCA's efficiency 
standards for low-voltage dry-type distribution transformers, 42 U.S.C. 
6295(y), manufacturers will have to determine the efficiencies of any 
such transformers they produce. This necessarily entails the use of 
testing and rating methods, and if DOE does not prescribe such methods, 
manufacturers would still be subject to the burden of using such tools. 
In addition, as noted above, EPCA requires DOE to prescribe testing 
requirements for any transformers subject to standards, and states that 
these requirements ``shall be based on'' NEMA TP 2-1998. 42 U.S.C. 
6293(b)(10) and 6317(a). Although these provisions allow the Department 
substantial discretion in prescribing a test method for distribution 
transformers, they indicate that EPCA contemplates that the DOE method 
likely would impose burdens equivalent or similar to those imposed by 
NEMA TP 2-1998. Thus, today's rule itself has an impact on small 
manufacturers only to the extent it imposes an incremental burden 
beyond what they would be required to do to comply with EPCA's 
standards or NEMA TP 2-1998.
    This is significant under the Regulatory Flexibility Act because 
the Act applies only where the agency's rule has a significant impact 
on small entities. It does not apply to a rule if the agency certifies 
that ``the rule will not * * * have a significant impact on a 
substantial number of small entities.'' 5 U.S.C. 605(a) (Emphasis 
added). Thus, the Act does not apply, for example, where the agency 
merely incorporates statutory requirements into its rules, or adopts 
the equivalent of statutory requirements without adding any significant 
impact on small entities. In such instances, it is the statutory 
requirements, and not the agency's rule, that could have an impact on 
small entities. The Department therefore examines in the following 
paragraphs whether today's rule imposes any burdens on small entities 
beyond those imposed by EPCA.
    In prescribing efficiency rating methods, today's rule (1) 
addresses the number of its basic models a manufacturer must rate 
through actual testing and how may units of each it must test, (2) 
prescribes a detailed method for testing each unit, and (3) provides 
for use of alternative efficiency determination methods for 
transformers that manufacturers do not rate through testing. See 
Section 431.193 and 431.197 of the attached rule. As to whether today's 
method for testing each unit is more burdensome than NEMA TP 2-1998, 
the two are nearly identical except that the Department's method adds 
technical detail, clarifying language, and editorial improvements. 
Thus, the DOE method is no more burdensome, and may alleviate burden 
because it reduces the need for manufacturers to do background work to 
provide missing details and clarify ambiguous provisions.
    Nor does today's test method impose significantly, if any, more 
burden than other methods a small manufacturer might reasonably use to 
comply with the EPACT standards for low-voltage dry-type transformers. 
A manufacturer might choose to use NEMA TP 2-1998, which as just 
indicated is no more burdensome than today's method, or NEMA TP 2-2005, 
which is almost word-for-word the same as the SNOPR's test method and 
which varies little from today's rule. A manufacturer might also craft 
a test method from the standards of accepted engineering practice as 
set forth in IEEE standards. On the one hand, except for the 
requirements as to equipment calibration in today's rule, the test 
method in the rule is the equivalent to the method in the four relevant 
IEEE standards. On the other hand, DOE believes it is possible that 
small manufacturers might each be able to modify the details of the 
IEEE test method so as to best fit its products. As a result its costs 
of testing needed to comply with the EPACT efficiency standards, i.e., 
implicit in the EPACT requirements, could be lower than the cost of 
testing under the test method in today's rule. The Department believes 
that such savings would not be significant, and to some extent would be 
offset by the resources a small manufacturer would have to expend to 
research and develop such a customized test method. Today's method does 
include requirements to calibrate equipment and maintain records of 
such calibrations, which are not explicitly included in the IEEE 
standards. But to achieve the accuracy levels required under these 
standards, a manufacturer would have to engage in some calibration 
effort. In any event, DOE estimates that today's rule would

[[Page 24993]]

require only about one week of staff time to satisfy the calibration 
requirements in the first year the rule is operative, and about two 
days a year thereafter. For the foregoing reasons, the Department 
concludes that, although today's test method might impose modest 
burdens on small manufacturers of low-voltage dry-type distribution 
transformers, these burdens are not significant.
    However, the final rule's provisions as to the amount of testing 
required to rate distribution transformer efficiencies are clearly far 
less burdensome to small manufacturers than methodologies currently in 
use. The rule requires each manufacturer to test at least five basic 
models. For each such model, the manufacturer must test the lesser of 
all units manufactured over a 180 day period or five units, and must 
rate the basic model's efficiency by applying a formula to the test 
results. The rule also allows use of AEDMs to rate the remaining basic 
models. The IEEE standards contain no provision for sampling, or for 
use of AEDMs, in rating the efficiency of distribution transformers. 
Moreover, DOE understands that, under current practice, where a 
manufacturer must rate a low-voltage dry-type transformer's losses--the 
equivalent of efficiency determination--typically it will test all 
units and rate them based on their average efficiency. Although, as 
explained below in footnote 6, EPCA does not direct DOE to use the 
sampling regimen in NEMA TP 2-1998, that is a methodology a 
manufacturer might use to determine whether its low-voltage dry-type 
transformers comply with EPCA's standards. NEMA TP 2-1998's sampling 
plan provides that, over a 180-day period, either all units 
manufactured be tested, or that five or more units per month be tested, 
thus requiring approximately six times as much testing as today's rule. 
It also contains no provision for rating transformer efficiencies 
through use of AEDMs. As explained in the SNOPR, 69 FR 45514-15, NEMA 
TP 2-1998 clearly requires considerably more testing that today's final 
rule (which requires the same amount of testing as DOE's proposal in 
the SNOPR).
    Insofar as the final rule's reduction in testing burden results 
from the use of AEDMs, however, this benefit is not without cost. The 
Department estimates that a manufacturer would have to incur 
approximately three to six weeks of engineering staff time to develop a 
valid AEDM, and approximately two weeks of staff time to administer and 
maintain the AEDM(s) thereafter. The Department estimates, however, 
that use of AEDMs would allow a manufacturer to do less than 20 percent 
of the testing that would otherwise be required.
    For all of these reasons, the Department certifies that today's 
final rule would not have a significant economic impact on a 
substantial number of small entities. Accordingly, DOE has not prepared 
a regulatory flexibility analysis for this rulemaking. DOE has 
transmitted the certification and supporting statement of factual basis 
to the Chief Counsel for Advocacy of the Small Business Administration 
for review pursuant to 5 U.S.C. 605(b).

C. Review Under the Paperwork Reduction Act

    As indicated in the SNOPR, today's final rule contains certain 
record-keeping requirements. 69 FR 45517. The situation with respect to 
the Paperwork Reduction Act (44 U.S.C. 3501 et seq.) is similar to that 
described in Section III.B. with respect to the Regulatory Flexibility 
Act. For the reasons stated there, unless and until the Department 
requires manufacturers to comply with energy conservation standards for 
medium-voltage and liquid immersed distribution transformers, no 
manufacturer of those products would be required to comply with these 
record-keeping provisions. Therefore, today's rule would not impose on 
those manufacturers any new reporting requirements requiring clearance 
by OMB under the Paperwork Reduction Act. The Department recognizes, 
however, as also set forth in the SNOPR, that if it adopts standards 
for those distribution transformers, once the standards become 
operative manufacturers will become subject to the record-keeping 
requirements in today's rule, and possibly additional reporting and/or 
record-keeping requirements. 69 FR 45517.
    We received no comments on this issue. For medium-voltage and 
liquid immersed distribution transformers, the Department intends, as 
stated in the SNOPR, to comply with the Paperwork Reduction Act with 
respect to the record-keeping requirements in today's rule at the 
appropriate point in conjunction with the standards development 
rulemaking.
    Since the publication of the SNOPR, however, the Department has 
adopted standards prescribed by EPCA for low-voltage dry-type 
distribution transformers. When these standards become operative on 
January 1, 2007, manufacturers of those products will be required to 
comply with the record-keeping provisions in today's rule. Therefore, 
as to these manufacturers today's final rule contains certain record-
keeping requirements that must be approved by the OMB pursuant to the 
Paperwork Reduction Act before the manufacturers may be required to 
comply with them. Section 431.197(a)(4)(i) would require manufacturers 
of distribution transformers to have records as to alternative 
efficiency determination methods available for DOE inspection; section 
6.2 of Appendix A would require maintenance of calibration records. As 
a result, concurrent with or shortly after publication of today's rule, 
the Department will issue a notice seeking public comment under the 
Paperwork Reduction Act, with respect to these manufacturers, on the 
record-keeping requirements in today's rule. After considering any 
public comments received in response to that notice, DOE will submit 
the proposed collection of information to OMB for approval pursuant to 
44 U.S.C. 3507.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. As stated in the ``EFFECTIVE DATE'' 
line of this notice of final rulemaking, the information collection 
requirements in Sec.  431.197(a)(4)(i) and section 6.2(b) and (c) of 
Appendix A will not become effective until OMB approves them. The 
Department will publish a document in the Federal Register advising 
low-voltage dry-type manufacturers of their effective date. That 
document also will display the OMB control number.

D. Review Under the National Environmental Policy Act of 1969

    DOE has determined that this rule falls into a class of actions 
that are categorically excluded from review under the National 
Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and the 
Department's implementing regulations at 10 CFR part 1021. 
Specifically, this rule establishing test procedures will not affect 
the quality or distribution of energy and, will not result in any 
environmental impacts, and, therefore, is covered by the Categorical 
Exclusion in paragraph A6 to subpart D, 10 CFR part 1021. Accordingly, 
neither an environmental assessment nor an environmental impact 
statement is required.

E. Review Under Executive Order 13132

    Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 4, 
1999), imposes certain requirements on agencies formulating and 
implementing policies or regulations that preempt State law or that 
have federalism implications. The Executive Order requires agencies to

[[Page 24994]]

examine the constitutional and statutory authority supporting any 
action that would limit the policymaking discretion of the States and 
carefully assess the necessity for such actions. The Executive Order 
also requires agencies to have an accountable process to ensure 
meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications. 
On March 14, 2000, DOE published a statement of policy describing the 
intergovernmental consultation process it will follow in the 
development of such regulations 65 FR 13735. DOE has examined today's 
final rule and has determined that it does not preempt State law and 
does not have a substantial direct effect on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government. No further action is required by Executive Order 13132.

F. Review Under Executive Order 12988

    With respect to the review of existing regulations and the 
promulgation of new regulations, section 3(a) of Executive Order 12988, 
``Civil Justice Reform'' (61 FR 4729, February 7, 1996), imposes on 
Federal agencies the general duty to adhere to the following 
requirements: (1) Eliminate drafting errors and ambiguity; (2) write 
regulations to minimize litigation; and (3) provide a clear legal 
standard for affected conduct rather than a general standard and 
promote simplification and burden reduction. Section 3(b) of Executive 
Order 12988 specifically requires that Executive agencies make every 
reasonable effort to ensure that the regulation: (1) Clearly specifies 
the preemptive effect, if any; (2) clearly specifies any effect on 
existing Federal law or regulation; (3) provides a clear legal standard 
for affected conduct while promoting simplification and burden 
reduction; (4) specifies the retroactive effect, if any; (5) adequately 
defines key terms; and (6) addresses other important issues affecting 
clarity and general draftsmanship under any guidelines issued by the 
Attorney General. Section 3(c) of Executive Order 12988 requires 
Executive agencies to review regulations in light of applicable 
standards in section 3(a) and section 3(b) to determine whether they 
are met or it is unreasonable to meet one or more of them. DOE has 
completed the required review and determined that, to the extent 
permitted by law, this rule meets the relevant standards of Executive 
Order 12988.

G. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Pub. 
L. 104-4) requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. For a proposed regulatory action likely to result in a 
rule that may cause the expenditure by State, local, and Tribal 
governments, in the aggregate, or by the private sector of $100 million 
or more in any one year (adjusted annually for inflation), section 202 
of UMRA requires a Federal agency to publish a written statement that 
estimates the resulting costs, benefits, and other effects on the 
national economy. (2 U.S.C. 1532(a), (b)) The UMRA also requires a 
Federal agency to develop an effective process to permit timely input 
by elected officers of State, local, and Tribal governments on a 
proposed ``significant intergovernmental mandate,'' and requires an 
agency plan for giving notice and opportunity for timely input to 
potentially affected small governments before establishing any 
requirements that might significantly or uniquely affect small 
governments. On March 18, 1997, DOE published a statement of policy on 
its process for intergovernmental consultation under UMRA. 62 FR 12820 
(also available at http://www.gc.doe.gov). Today's rule does not 
contain any Federal mandate likely to result in an aggregate 
expenditure of $100 million or more in any year, so these requirements 
under the Unfunded Mandates Reform Act do not apply.

H. Review Under the Treasury and General Government Appropriations Act 
of 1999

    Section 654 of the Treasury and General Government Appropriations 
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family 
Policymaking Assessment for any rule that may affect family well-being. 
This rule would not have any impact on the autonomy or integrity of the 
family as an institution. Accordingly, DOE has concluded that it is not 
necessary to prepare a Family Policymaking Assessment.

I. Review Under Executive Order 12630

    The Department has determined, under Executive Order 12630, 
``Governmental Actions and Interference with Constitutionally Protected 
Property Rights,'' 53 FR 8859 (March 18, 1988), that this regulation 
would not result in any takings which might require compensation under 
the Fifth Amendment to the United States Constitution.

J. Review Under the Treasury and General Government Appropriations Act, 
2001

    Section 515 of the Treasury and General Government Appropriations 
Act, 2001 (44 U.S.C. 3516 note) provides for agencies to review most 
disseminations of information to the public under guidelines 
established by each agency pursuant to general guidelines issued by 
OMB. OMB's guidelines were published at 67 FR 8452 (February 22, 2002), 
and DOE's guidelines were published at 67 FR 62446 (October 7, 2002). 
The Department has reviewed today's final rule under the OMB and DOE 
guidelines and has concluded that it is consistent with applicable 
policies in those guidelines.

K. Review Under Executive Order 13211

    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355 
(May 22, 2001) requires Federal agencies to prepare and submit to the 
Office of Information and Regulatory Affairs (OIRA), Office of 
Management and Budget, a Statement of Energy Effects for any proposed 
significant energy action. A ``significant energy action'' is defined 
as any action by an agency that promulgated or is expected to lead to 
promulgation of a final rule, and that: (1) Is a significant regulatory 
action under Executive Order 12866, or any successor order; and (2) is 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy, or (3) is designated by the 
Administrator of OIRA as a significant energy action. For any proposed 
significant energy action, the agency must give a detailed statement of 
any adverse effects on energy supply, distribution, or use should the 
proposal be implemented, and of reasonable alternatives to the action 
and their expected benefits on energy supply, distribution, and use.
    This final rule is not a significant regulatory action under 
Executive Order 12866 or any successor order. In addition, it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy, nor has it been designated by the 
Administrator of OIRA as a significant energy action. Thus, DOE has not 
prepared a Statement of Energy Effects.

[[Page 24995]]

L. Review Under Section 32 of the Federal Energy Administration Act of 
1974

    Under Section 301 of the Department of Energy Organization Act 
(Pub. L. 95-91), the Department must comply with Section 32 of the 
Federal Energy Administration Act of 1974 (FEAA), as amended by the 
Federal Energy Administration Authorization Act of 1977. (15 U.S.C. 
788) The Department indicated in the SNOPR that Section 32 applies to 
the portion of today's rule that incorporates testing methods contained 
in five commercial standards, requiring consultation with the Attorney 
General and the Chairman of the Federal Trade Commission concerning the 
impact of these standards on competition. 69 FR 45506, 45519 (July 29, 
2004).
    Since publication of the SNOPR, DOE has reviewed this requirement 
for consultation as it applies to this final rule. While DOE now 
believes that such consultation is not necessarily required for this 
rule, since DOE stated in the SNOPR that it would submit it for 
consultation under Section 32, it has done so. Neither the Attorney 
General nor the Chairman of the Federal Trade Commission has 
recommended against incorporation of these standards.

M. Congressional Notification

    As required by 5 U.S.C. 801, DOE will report to Congress on the 
promulgation of this rule prior to its effective date. The report will 
state that it has been determined that the rule is not a ``major rule'' 
as defined by 5 U.S.C. 804(2).

IV. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this final 
rule.

List of Subjects in 10 CFR Part 431

    Administrative practice and procedure, Distribution transformers, 
Energy conservation.

    Issued in Washington, DC, on March 28, 2006.
Douglas L. Faulkner,
Acting Assistant Secretary, Energy Efficiency and Renewable Energy.

0
For the reasons set forth in the preamble, Part 431 of Chapter II of 
Title 10, Code of Federal Regulations, is amended as set forth below.

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
1. The authority citation for Part 431 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317.

0
2. Section 431.191 is revised to read as follows:


Sec.  431.191  Purpose and scope.

    This subpart contains energy conservation requirements for 
distribution transformers, pursuant to Parts B and C of Title III of 
the Energy Policy and Conservation Act, as amended, 42 U.S.C. 6291-
6317.

0
3. Section 431.192 is amended by:
0
a. Revising the Section heading.
0
b. Adding introductory language.
0
c. Adding in alphabetical order definitions of ``autotransformer,'' 
``basic model,'' ``drive (isolation) transformer,'' ``efficiency,'' 
``excitation current or no-load current,'' ``grounding transformer,'' 
``liquid-immersed distribution transformer,'' ``load loss,'' ``machine-
tool (control) transformer,'' ``medium-voltage dry-type distribution 
transformer,'' ``no-load loss,'' ``nonventilated transformer,'' ``phase 
angle,'' ``phase angle correction,'' ``phase angle error,'' ``rectifier 
transformer,'' ``reference temperature,'' ``regulating transformer,'' 
``sealed transformer,'' ``special-impedance transformer,'' 
``temperature correction,'' ``test current,'' ``test frequency,'' 
``test voltage,'' ``testing transformer,'' ``total loss,'' 
``transformer with tap range of 20 percent or more,'' ``uninterruptible 
power supply transformer,'' ``waveform correction,'' and ``welding 
transformer.''
0
d. Revising the definition of ``distribution transformer.''
    The revision and additions read as follows:


Sec.  431.192  Definitions.

    The following definitions apply for purposes of this subpart:
    Autotransformer means a transformer that:
    (1) Has one physical winding that consists of a series winding part 
and a common winding part;
    (2) Has no isolation between its primary and secondary circuits; 
and
    (3) During step-down operation, has a primary voltage that is equal 
to the total of the series and common winding voltages, and a secondary 
voltage that is equal to the common winding voltage.
    Basic model means a group of models of distribution transformers 
manufactured by a single manufacturer, that have the same insulation 
type (i.e., liquid-immersed or dry-type), have the same number of 
phases (i.e., single or three), have the same standard kVA rating, and 
do not have any differentiating electrical, physical or functional 
features that affect energy consumption. Differences in voltage and 
differences in basic impulse insulation level (BIL) rating are examples 
of differentiating electrical features that affect energy consumption.
    Distribution transformer means a transformer that--
    (1) Has an input voltage of 34.5 kV or less;
    (2) Has an output voltage of 600 V or less;
    (3) Is rated for operation at a frequency of 60 Hz; and
    (4) Has a capacity of 10 kVA to 2500 kVA for liquid-immersed units 
and 15 kVA to 2500 kVA for dry-type units; but
    (5) The term ``distribution transformer'' does not include a 
transformer that is an--
    (i) Autotransformer;
    (ii) Drive (isolation) transformer;
    (iii) Grounding transformer;
    (iv) Machine-tool (control) transformer;
    (v) Nonventilated transformer;
    (vi) Rectifier transformer;
    (vii) Regulating transformer;
    (viii) Sealed transformer;
    (ix) Special-impedance transformer;
    (x) Testing transformer;
    (xi) Transformer with tap range of 20 percent or more;
    (xii) Uninterruptible power supply transformer; or
    (xiii) Welding transformer.
    Drive (isolation) transformer means a transformer that:
    (1) Isolates an electric motor from the line;
    (2) Accommodates the added loads of drive-created harmonics; and
    (3) Is designed to withstand the additional mechanical stresses 
resulting from an alternating current adjustable frequency motor drive 
or a direct current motor drive.
    Efficiency means the ratio of the useful power output to the total 
power input.
    Excitation current or no-load current means the current that flows 
in any winding used to excite the transformer when all other windings 
are open-circuited.
    Grounding transformer means a three-phase transformer intended 
primarily to provide a neutral point for system-grounding purposes, 
either by means of:
    (1) A grounded wye primary winding and a delta secondary winding; 
or
    (2) A transformer with its primary winding in a zig-zag winding 
arrangement, and with no secondary winding.
    Liquid-immersed distribution transformer means a distribution 
transformer in which the core and coil assembly is immersed in an 
insulating liquid.
    Load loss means, for a distribution transformer, those losses 
incident to a specified load carried by the

[[Page 24996]]

transformer, including losses in the windings as well as stray losses 
in the conducting parts of the transformer.
* * * * *
    Machine-tool (control) transformer means a transformer that is 
equipped with a fuse or other over-current protection device, and is 
generally used for the operation of a solenoid, contactor, relay, 
portable tool, or localized lighting.
    Medium-voltage dry-type distribution transformer means a 
distribution transformer in which the core and coil assembly is 
immersed in a gaseous or dry-compound insulating medium, and which has 
a rated primary voltage between 601 V and 34.5 kV.
    No-load loss means those losses that are incident to the excitation 
of the transformer.
    Nonventilated transformer means a transformer constructed so as to 
prevent external air circulation through the coils of the transformer 
while operating at zero gauge pressure.
    Phase angle means the angle between two phasors, where the two 
phasors represent progressions of periodic waves of either:
    (1) Two voltages;
    (2) Two currents; or
    (3) A voltage and a current of an alternating current circuit.
    Phase angle correction means the adjustment (correction) of 
measurement data to negate the effects of phase angle error.
    Phase angle error means incorrect displacement of the phase angle, 
introduced by the components of the test equipment.
    Rectifier transformer means a transformer that operates at the 
fundamental frequency of an alternating-current system and that is 
designed to have one or more output windings connected to a rectifier.
    Reference temperature means 20 [deg]C for no-load loss, 55 [deg]C 
for load loss of liquid-immersed distribution transformers at 50 
percent load, and 75 [deg]C for load loss of both low-voltage and 
medium-voltage dry-type distribution transformers, at 35 percent load 
and 50 percent load, respectively. It is the temperature at which the 
transformer losses must be determined, and to which such losses must be 
corrected if testing is done at a different point. (These temperatures 
are specified in the test method in Appendix A to this part.)
    Regulating transformer means a transformer that varies the voltage, 
the phase angle, or both voltage and phase angle, of an output circuit 
and compensates for fluctuation of load and input voltage, phase angle 
or both voltage and phase angle.
    Sealed transformer means a transformer designed to remain 
hermetically sealed under specified conditions of temperature and 
pressure.
    Special-impedance transformer means any transformer built to 
operate at an impedance outside of the normal impedance range for that 
transformer's kVA rating. The normal impedance range for each kVA 
rating for liquid-immersed and dry-type transformers is shown in Tables 
1 and 2, respectively.

                       Table 1.--Normal Impedance Ranges for Liquid-Immersed Transformers
----------------------------------------------------------------------------------------------------------------
                            Single-phase transformers                                Three-phase transformers
----------------------------------------------------------------------------------------------------------------
                               kVA                                Impedance  (%)        kVA       Impedance  (%)
----------------------------------------------------------------------------------------------------------------
10..............................................................         1.0-4.5              15         1.0-4.5
15..............................................................         1.0-4.5              30         1.0-4.5
25..............................................................         1.0-4.5              45         1.0-4.5
37.5............................................................         1.0-4.5              75         1.0-5.0
50..............................................................         1.5-4.5           112.5         1.2-6.0
75..............................................................         1.5-4.5             150         1.2-6.0
100.............................................................         1.5-4.5             225         1.2-6.0
167.............................................................         1.5-4.5             300         1.2-6.0
250.............................................................         1.5-6.0             500         1.5-7.0
333.............................................................         1.5-6.0             750         5.0-7.5
500.............................................................         1.5-7.0            1000         5.0-7.5
667.............................................................         5.0-7.5            1500         5.0-7.5
833.............................................................         5.0-7.5            2000         5.0-7.5
                                                                                            2500         5.0-7.5
----------------------------------------------------------------------------------------------------------------


                           Table 2.--Normal Impedance Ranges for Dry-Type Transformers
----------------------------------------------------------------------------------------------------------------
                            Single-phase transformers                                Three-phase transformers
----------------------------------------------------------------------------------------------------------------
                               kVA                                Impedance  (%)        kVA       Impedance  (%)
----------------------------------------------------------------------------------------------------------------
15..............................................................         1.5-6.0              15         1.5-6.0
25..............................................................         1.5-6.0              30         1.5-6.0
37.5............................................................         1.5-6.0              45         1.5-6.0
50..............................................................         1.5-6.0              75         1.5-6.0
75..............................................................         2.0-7.0           112.5         1.5-6.0
100.............................................................         2.0-7.0             150         1.5-6.0
167.............................................................         2.5-8.0             225         3.0-7.0
250.............................................................         3.5-8.0             300         3.0-7.0
333.............................................................         3.5-8.0             500         4.5-8.0
500.............................................................         3.5-8.0             750         5.0-8.0
667.............................................................         5.0-8.0            1000         5.0-8.0
833.............................................................         5.0-8.0            1500         5.0-8.0
                                                                                            2000         5.0-8.0
                                                                                            2500         5.0-8.0
----------------------------------------------------------------------------------------------------------------


[[Page 24997]]

    Temperature correction means the mathematical correction(s) of 
measurement data, obtained when a transformer is tested at a 
temperature that is different from the reference temperature, to the 
value(s) that would have been obtained if the transformer had been 
tested at the reference temperature.
    Test current means the current of the electrical power supplied to 
the transformer under test.
    Test frequency means the frequency of the electrical power supplied 
to the transformer under test.
    Test voltage means the voltage of the electrical power supplied to 
the transformer under test.
    Testing transformer means a transformer used in a circuit to 
produce a specific voltage or current for the purpose of testing 
electrical equipment.
    Total loss means the sum of the no-load loss and the load loss for 
a transformer.
* * * * *
    Transformer with tap range of 20 percent or more means a 
transformer with multiple voltage taps, the highest of which equals at 
least 20 percent more than the lowest, computed based on the sum of the 
deviations of the voltages of these taps from the transformer's nominal 
voltage.
    Uninterruptible power supply transformer means a transformer that 
supplies power to an uninterruptible power system, which in turn 
supplies power to loads that are sensitive to power failure, power 
sags, over voltage, switching transients, line noise, and other power 
quality factors.
    Waveform correction means the adjustment(s) (mathematical 
correction(s)) of measurement data obtained with a test voltage that is 
non-sinusoidal, to a value(s) that would have been obtained with a 
sinusoidal voltage.
    Welding transformer means a transformer designed for use in arc 
welding equipment or resistance welding equipment.

0
4. Section 431.193 is added to subpart K, under the heading ``Test 
Procedures,'' to read as follows:

Test Procedures


Sec.  431.193  Test procedures for measuring energy consumption of 
distribution transformers.

    The test procedures for measuring the energy efficiency of 
distribution transformers for purposes of EPCA are specified in 
Appendix A to this subpart.

0
5. Section 431.196 is amended in paragraph (a) by revising the table to 
read as follows:


Sec.  431.196  Energy conservation standards and their effective dates.

    (a) * * *

----------------------------------------------------------------------------------------------------------------
                                  Single phase                                              Three phase
----------------------------------------------------------------------------------------------------------------
                                                                  Efficiency (%)                  Efficiency (%)
                               kVA                                      \1\             kVA             \1\
----------------------------------------------------------------------------------------------------------------
15..............................................................            97.7              15            97.0
25..............................................................            98.0              30            97.5
37.5............................................................            98.2              45            97.7
50..............................................................            98.3              75            98.0
75..............................................................            98.5           112.5            98.2
100.............................................................            98.6             150            98.3
167.............................................................            98.7             225            98.5
250.............................................................            98.8             300            98.6
333.............................................................            98.9             500            98.7
                                                                                             750            98.8
                                                                                            1000            98.9
----------------------------------------------------------------------------------------------------------------
\1\ Efficiencies are determined at the following reference conditions: (1) for no-load losses, at the
  temperature of 20 [deg]C, and (2) for load-losses, at the temperature of 75 [deg]C and 35 percent of nameplate
  load.
(Source: Table 4-2 of National Electrical Manufacturers Association (NEMA) Standard TP-1-2002, ``Guide for
  Determining Energy Efficiency for Distribution Transformers.'')

* * * * *

0
6. Sections 431.197 through 431.198 are added to subpart K, under the 
heading ``Compliance and Enforcement,'' to read as follows:

Compliance and Enforcement


Sec.  431.197  Manufacturer's determination of efficiency for 
distribution transformers.

    When a manufacturer or other party (both of which this section 
refers to as a ``manufacturer'') determines the efficiency of a 
distribution transformer in order to comply with an obligation imposed 
on it by or pursuant to Part C of Title III of EPCA, 42 U.S.C. 6311-
6317, this section applies. This section does not apply to enforcement 
testing conducted pursuant to Sec.  431.198 of this part.
    (a) Methods used to determine efficiency--(1) General requirements. 
A manufacturer must determine the efficiency of each basic model of 
distribution transformer either by testing, in accordance with Sec.  
431.193 of this part and paragraphs (b)(2) and (b)(3) of this section, 
or by application of an alternative efficiency determination method 
(AEDM) that meets the requirements of paragraphs (a)(2) and (a)(3) of 
this section; provided, however, that a manufacturer may use an AEDM to 
determine the efficiency of one or more of its untested basic models 
only if it determines the efficiency of at least five of its other 
basic models (selected in accordance with paragraph (b)(1) of this 
section) through actual testing. For each basic model of distribution 
transformer that has a configuration of windings which allows for more 
than one nominal rated voltage, the manufacturer must determine the 
basic model's efficiency either at the voltage at which the highest 
losses occur or at each voltage at which the transformer is rated to 
operate.
    (2) Alternative efficiency determination method. A manufacturer may 
apply an AEDM to a basic model pursuant to paragraph (a)(1) of this 
section only if:
    (i) The AEDM has been derived from a mathematical model that 
represents the electrical characteristics of that basic model;
    (ii) The AEDM is based on engineering and statistical analysis, 
computer simulation or modeling, or other analytic evaluation of 
performance data; and
    (iii) The manufacturer has substantiated the AEDM, in accordance 
with paragraph (a)(3) of this section, by applying it to, and testing, 
at least five

[[Page 24998]]

other basic models of the same type, i.e., low-voltage dry-type 
distribution transformers, medium-voltage dry-type distribution 
transformers, or liquid-immersed distribution transformers.
    (3) Substantiation of an alternative efficiency determination 
method. Before using an AEDM, the manufacturer must substantiate the 
AEDM's accuracy and reliability as follows:
    (i) Apply the AEDM to at least five of the manufacturer's basic 
models that have been selected for testing in accordance with paragraph 
(b)(1) of this section, and calculate the power loss for each of these 
basic models;
    (ii) Test at least five units of each of these basic models in 
accordance with the applicable test procedure and paragraph (b)(2) of 
this section, and determine the power loss for each of these basic 
models;
    (iii) The predicted total power loss for each of these basic 
models, calculated by applying the AEDM pursuant to paragraph (a)(3)(i) 
of this section, must be within plus or minus five percent of the mean 
total power loss determined from the testing of that basic model 
pursuant to paragraph (a)(3)(ii) of this section; and
    (iv) Calculate for each of these basic models the percentage that 
its power loss calculated pursuant to paragraph (a)(3)(i) is of its 
power loss determined from testing pursuant to paragraph (a)(3)(ii), 
compute the average of these percentages, and that calculated average 
power loss, expressed as a percentage of the average power loss 
determined from testing, must be no less than 97 percent and no greater 
than 103 percent.
    (4) Subsequent verification of an AEDM. (i) Each manufacturer that 
has used an AEDM under this section shall have available for inspection 
by the Department of Energy records showing: The method or methods 
used; the mathematical model, the engineering or statistical analysis, 
computer simulation or modeling, and other analytic evaluation of 
performance data on which the AEDM is based; complete test data, 
product information, and related information that the manufacturer has 
generated or acquired pursuant to paragraph (a)(3) of this section; and 
the calculations used to determine the efficiency and total power 
losses of each basic model to which the AEDM was applied.
    (ii) If requested by the Department, the manufacturer shall conduct 
simulations to predict the performance of particular basic models of 
distribution transformers specified by the Department, analyses of 
previous simulations conducted by the manufacturer, sample testing of 
basic models selected by the Department, or a combination of the 
foregoing.
    (b) Additional testing requirements--(1) Selection of basic models 
for testing if an AEDM is to be applied. (i) A manufacturer must select 
basic models for testing in accordance with the following criteria:
    (A) Two of the basic models must be among the five basic models 
with the highest unit volumes of production by the manufacturer in the 
prior year, or during the prior 12-calendar-month period beginning in 
2003,\1\ whichever is later;
---------------------------------------------------------------------------

    \1\ When identifying these five basic models, any basic model 
that does not comply with Federal energy conservation standards for 
distribution transformers that may be in effect shall be excluded 
from consideration.
---------------------------------------------------------------------------

    (B) No two basic models should have the same combination of power 
and voltage ratings; and
    (C) At least one basic model should be single-phase and at least 
one should be three-phase.
    (ii) In any instance where it is impossible for a manufacturer to 
select basic models for testing in accordance with all of these 
criteria, the criteria shall be given priority in the order in which 
they are listed. Within the limits imposed by the criteria, basic 
models shall be selected randomly.
    (2) Selection of units for testing within a basic model. For each 
basic model a manufacturer selects for testing, it shall select and 
test units as follows:
    (i) If the manufacturer would produce five or fewer units of a 
basic model over a reasonable period of time (approximately 180 days), 
then it must test each unit. However, a manufacturer may not use a 
basic model with a sample size of fewer than five units to substantiate 
an AEDM pursuant to paragraph (a)(3) of this section.
    (ii) If the manufacturer produces more than five units over such 
period of time, it must either test all such units or select a sample 
of at least five units at random and test them. Any such sample shall 
be comprised of production units of the basic model, or units that are 
representative of such production units.
    (3) Applying results of testing. In a test of compliance with a 
represented efficiency, the average efficiency of the sample, X, which 
is defined by
[GRAPHIC] [TIFF OMITTED] TR27AP06.000


where Xi is the measured efficiency of unit i and n is the 
number of units tested, must satisfy the condition:
[GRAPHIC] [TIFF OMITTED] TR27AP06.001


where RE is the represented efficiency.


Sec.  431.198  Enforcement testing for distribution transformers.

    (a) Test notice. Upon receiving information in writing, concerning 
the energy performance of a particular distribution transformer sold by 
a particular manufacturer or private labeler, which indicates that the 
transformer may not be in compliance with the applicable energy 
efficiency standard, or upon undertaking to ascertain the accuracy of 
the efficiency rating on the nameplate or in marketing materials for a 
distribution transformer, disclosed pursuant to this part, the 
Department may conduct testing of that equipment under this subpart by 
means of a test notice addressed to the manufacturer in accordance with 
the following requirements:
    (1) The test notice procedure will only be followed after the 
Department has examined the underlying test data (or, where 
appropriate, data as to use of an AEDM) provided by the manufacturer 
and after the manufacturer has been offered the opportunity to meet 
with the Department to verify, as applicable, compliance with the 
applicable efficiency standard, or the accuracy of labeling 
information, or both. In addition, where compliance of a basic model 
was certified based on an AEDM, the Department shall have the 
discretion to pursue the provisions of Sec.  431.197(a)(4)(ii) prior to 
invoking the test notice procedure. The Department shall be permitted 
to observe any reverification procedures undertaken pursuant to this 
subpart, and to inspect the results of such reverification.
    (2) The Department will mail or deliver the test notice to the 
plant manager or other responsible official, as designated by the 
manufacturer.
    (3) The test notice will specify the basic model(s) to be selected 
for testing, the method of selecting the test sample, the date and time 
at which testing shall be initiated, the date by which testing is 
scheduled to be completed and the facility at which testing will be 
conducted. The test notice may also provide for situations in which a 
specified basic model is unavailable for testing, and may include 
alternative basic models. The specified basic model may be one either 
that the manufacturer has rated by actual testing or that it has rated 
by the use of an AEDM.
    (4) The Department may require in the test notice that the 
manufacturer shall

[[Page 24999]]

ship at its expense a reasonable number of units of each basic model 
specified in such test notice to a testing laboratory designated by the 
Department. The number of units of each basic model specified in a test 
notice shall not exceed twenty (20).
    (5) Except as required or provided in paragraphs (a)(6) or (a)(7) 
of this section, initially the Department will test five units.
    (6) Except as provided in paragraph (a)(7) of this section, if 
fewer than five units of a basic model are available for testing when 
the manufacturer receives the test notice, then
    (i) DOE will test the available unit(s); or
    (ii) If one or more other units of the basic model are expected to 
become available within six months, DOE may instead, at its discretion, 
test either:
    (A) The available unit(s) and one or more of the other units that 
subsequently become available (up to a maximum of twenty); or
    (B) Up to twenty of the other units that subsequently become 
available.
    (7) Notwithstanding paragraphs (a)(5) and (a)(6) of this section, 
if testing of the available or subsequently available units of a basic 
model would be impractical, as for example where a basic model is very 
large, has unusual testing requirements, or has limited production, the 
Department may in its discretion decide to base the determination of 
compliance on the testing of fewer than the available number of units, 
if the manufacturer so requests and demonstrates that the criteria of 
this paragraph are met.
    (8) When testing units under paragraphs (a)(5), (a)(6), or (a)(7) 
of this section, DOE shall perform the following number of tests:
    (i) If DOE tests four or more units, it will test each unit once;
    (ii) If DOE tests two or three units, it will test each unit twice; 
or
    (iii) If DOE tests one unit, it will test that unit four times.
    (9) Within five working days of the time the units are selected, 
the manufacturer shall ship the specified test units of the basic model 
to the testing laboratory.
    (b) Testing laboratory. Whenever the Department conducts 
enforcement testing at a designated laboratory in accordance with a 
test notice under this section, the resulting test data shall 
constitute official test data for that basic model. Such test data will 
be used by the Department to make a determination of compliance or 
noncompliance.
    (c) Sampling. The determination that a manufacturer's basic model 
complies with its labeled efficiency, or the applicable energy 
efficiency standard, shall be based on the testing conducted in 
accordance with the statistical sampling procedures set forth in 
Appendix B of this subpart and the test procedures specified for 
distribution transformers.
    (d) Test unit selection. The Department shall select a batch, a 
batch sample, and test units from the batch sample in accordance with 
the following provisions of this paragraph and the conditions specified 
in the test notice.
    (1) The batch may be subdivided by the Department utilizing 
criteria specified in the test notice.
    (2) The Department will then randomly select a batch sample of up 
to 20 units from one or more subdivided groups within the batch. The 
manufacturer shall keep on hand all units in the batch sample until 
such time as the basic model is determined to be in compliance or non-
compliance.
    (3) The Department will randomly select individual test units 
comprising the test sample from the batch sample.
    (4) All random selection shall be achieved by sequentially 
numbering all of the units in a batch sample and then using a table of 
random numbers to select the units to be tested.
    (e) Test unit preparation. (1) Prior to and during the testing, a 
test unit selected in accordance with paragraph (d) of this section 
shall not be prepared, modified, or adjusted in any manner unless such 
preparation, modification, or adjustment is allowed by the applicable 
Department of Energy test procedure.
    (2) No quality control, testing, or assembly procedures shall be 
performed on a test unit, or any parts and sub-assemblies thereof, that 
is not performed during the production and assembly of all other units 
included in the basic model.
    (3) A test unit shall be considered defective if such unit is 
inoperative or is found to be in noncompliance due to failure of the 
unit to operate according to the manufacturer's design and operating 
instructions. Defective units, including those damaged due to shipping 
or handling, shall be reported immediately to the Department. The 
Department shall authorize testing of an additional unit on a case-by-
case basis.
    (f) Testing at manufacturer's option. (1) If a manufacturer's basic 
model is determined to be in noncompliance with the applicable energy 
performance standard at the conclusion of Department testing in 
accordance with the sampling plan specified in Appendix B of this 
subpart, the manufacturer may request that the Department conduct 
additional testing of the basic model according to procedures set forth 
in Appendix B of this subpart and the test procedures specified for 
distribution transformers.
    (2) All units tested under this paragraph (f) shall be selected and 
tested in accordance with the provisions given in paragraphs (a)(9), 
(b), (d) and (e) of this section.
    (3) The manufacturer shall bear the cost of all testing conducted 
under this paragraph (f).
    (4) The manufacturer shall cease distribution of the basic model 
tested under the provisions of this paragraph from the time the 
manufacturer elects to exercise the option provided in this paragraph 
until the basic model is determined to be in compliance. The Department 
may seek civil penalties for all units distributed during such period.
    (5) If the additional testing results in a determination of 
compliance, a notice of allowance to resume distribution shall be 
issued by the Department.

0
7. Appendices A and B are added to subpart K, to read as follows:

Appendix A to Subpart K of Part 431--Uniform Test Method for Measuring 
the Energy Consumption of Distribution Transformers

1.0 Definitions.

    The definitions contained in Sec. Sec.  431.2 and 431.192 are 
applicable to this Appendix A.

2.0 Accuracy Requirements.

    (a) Equipment and methods for loss measurement shall be 
sufficiently accurate that measurement error will be limited to the 
values shown in Table 2.1.

Table 2.1.--Test System Accuracy Requirements for Each Measured Quantity
------------------------------------------------------------------------
             Measured quantity                  Test system  accuracy
------------------------------------------------------------------------
Power Losses..............................   3.0%
Voltage...................................   0.5%
Current...................................   0.5%
Resistance................................   0.5%
Temperature...............................   1.0 [deg]C
------------------------------------------------------------------------

    (b) Only instrument transformers meeting the 0.3 metering 
accuracy class, or better, may be used under this test method.

3.0 Resistance Measurements

    3.1 General Considerations
    (a) Measure or establish the winding temperature at the time of 
the winding resistance measurement.
    (b) Measure the direct current resistance (Rdc) of 
transformer windings by one of the methods outlined in section 3.3. 
The methods of section 3.5 must be used to correct load losses to 
the applicable reference temperature from the temperature at which 
they are measured. Observe precautions

[[Page 25000]]

while taking measurements, such as those in section 3.4, in order to 
maintain measurement uncertainty limits specified in Table 2.1.
    3.2 Temperature Determination of Windings and Pre-conditions for 
Resistance Measurement.
    Make temperature measurements in protected areas where the air 
temperature is stable and there are no drafts. Determine the winding 
temperature (Tdc) for liquid-immersed and dry-type 
distribution transformers by the methods described in sections 3.2.1 
and 3.2.2, respectively.
    3.2.1 Liquid-Immersed Distribution Transformers.

3.2.1.1 Methods

    Record the winding temperature (Tdc) of liquid-
immersed transformers as the average of either of the following:
    (a) The measurements from two temperature sensing devices (for 
example, thermocouples) applied to the outside of the transformer 
tank and thermally insulated from the surrounding environment, with 
one located at the level of the oil and the other located near the 
tank bottom or at the lower radiator header if applicable; or
    (b) The measurements from two temperature sensing devices 
immersed in the transformer liquid, with one located directly above 
the winding and other located directly below the winding.

3.2.1.2 Conditions

    Make this determination under either of the following 
conditions:
    (a) The windings have been under insulating liquid with no 
excitation and no current in the windings for four hours before the 
dc resistance is measured; or
    (b) The temperature of the insulating liquid has stabilized, and 
the difference between the top and bottom temperature does not 
exceed 5 [deg]C.
    3.2.2 Dry-Type Distribution Transformers.
    Record the winding temperature (Tdc) of dry-type 
transformers as either of the following:
    (a) For ventilated dry-type units, use the average of readings 
of four or more thermometers, thermocouples, or other suitable 
temperature sensors inserted within the coils. Place the sensing 
points of the measuring devices as close as possible to the winding 
conductors. For sealed units, such as epoxy-coated or epoxy-
encapsulated units, use the average of four or more temperature 
sensors located on the enclosure and/or cover, as close to different 
parts of the winding assemblies as possible; or
    (b) For both ventilated and sealed units, use the ambient 
temperature of the test area, under the following conditions:
    (1) All internal temperatures measured by the internal 
temperature sensors must not differ from the test area ambient 
temperature by more than 2 [deg]C.
    (2) Enclosure surface temperatures for sealed units must not 
differ from the test area ambient temperature by more than 2 [deg]C.
    (3) Test area ambient temperature should not have changed by 
more than 3 [deg]C for 3 hours before the test.
    (4) Neither voltage nor current has been applied to the unit 
under test for 24 hours. In addition, increase this initial 24 hour 
period by any added amount of time necessary for the temperature of 
the transformer windings to stabilize at the level of the ambient 
temperature. However, this additional amount of time need not exceed 
24 hours.
    3.3 Resistance Measurement Methods.
    Make resistance measurements using either the resistance bridge 
method, the voltmeter-ammeter method or a resistance meter. In each 
instance when this Uniform Test Method is used to test more than one 
unit of a basic model to determine the efficiency of that basic 
model, the resistance of the units being tested may be determined 
from making resistance measurements on only one of the units.
    3.3.1 Resistance Bridge Methods.
    If the resistance bridge method is selected, use either the 
Wheatstone or Kelvin bridge circuit (or the equivalent of either).

3.3.1.1 Wheatstone Bridge

    (a) This bridge is best suited for measuring resistances larger 
than ten ohms. A schematic diagram of a Wheatstone bridge with a 
representative transformer under test is shown in Figure 3.1.
[GRAPHIC] [TIFF OMITTED] TR27AP06.002

Where:

Rdc is the resistance of the transformer winding being 
measured,
Rs is a standard resistor having the resistance 
Rs,
Ra, Rb are two precision resistors with 
resistance values Ra and Rb , respectively; at 
least one resistor must have a provision for resistance adjustment,
Rt is a resistor for reducing the time constant of the 
circuit,
D is a null detector, which may be either a micro ammeter or 
microvoltmeter or equivalent instrument for observing that no signal 
is present when the bridge is balanced, and
Vdc is a source of dc voltage for supplying the power to 
the Wheatstone Bridge.

    (b) In the measurement process, turn on the source 
(Vdc), and adjust the resistance ratio (Ra/
Rb) to produce zero signal at the detector (D). Determine 
the winding resistance by using equation 3-1 as follows:


[[Page 25001]]


[GRAPHIC] [TIFF OMITTED] TR27AP06.003

3.3.1.2 Kelvin Bridge

    (a) This bridge separates the resistance of the connecting 
conductors to the transformer winding being measured from the 
resistance of the winding, and therefore is best suited for 
measuring resistances of ten ohms and smaller. A schematic diagram 
of a Kelvin bridge with a representative transformer under test is 
shown in Figure 3.2.

    [GRAPHIC] [TIFF OMITTED] TR27AP06.004
    
    (b) The Kelvin Bridge has seven of the same type of components 
as in the Wheatstone Bridge. It has two more resistors than the 
Wheatstone bridge, Ra1 and Rb1. At least one 
of these resistors must have adjustable resistance. In the 
measurement process, the source is turned on, two resistance ratios 
(Ra/Rb) and (Ra1/Rb1) 
are adjusted to be equal, and then the two ratios are adjusted 
together to balance the bridge producing zero signal at the 
detector. Determine the winding resistance by using equation 3-2 as 
follows:

[GRAPHIC] [TIFF OMITTED] TR27AP06.005

as with the Wheatstone bridge, with an additional condition that:

[GRAPHIC] [TIFF OMITTED] TR27AP06.006

    (c) The Kelvin bridge provides two sets of leads, current-
carrying and voltage-sensing, to the transformer terminals and the 
standard resistor, thus eliminating voltage drops from the 
measurement in the current-carrying leads as represented by 
Rd.
    3.3.2 Voltmeter-Ammeter Method.
    (a) Employ the voltmeter-ammeter method only if the rated 
current of the winding is greater than one ampere and the test 
current is limited to 15 percent of the winding current. Connect the 
transformer winding under test to the circuit shown in Figure 3.3.
[GRAPHIC] [TIFF OMITTED] TR27AP06.007

Where:

A is an ammeter or a voltmeter-shunt combination for measuring the 
current (Imdc) in the transformer winding,
V is a voltmeter with sensitivity in the millivolt range for 
measuring the voltage

[[Page 25002]]

(Vmdc) applied to the transformer winding,
Rdc is the resistance of the transformer winding being 
measured,
Rt is a resistor for reducing the time constant of the 
circuit, and
Vdc is a source of dc voltage for supplying power to the 
measuring circuit.

    (b) To perform the measurement, turn on the source to produce 
current no larger than 15 percent of the rated current for the 
winding. Wait until the current and voltage readings have stabilized 
and then take simultaneous readings of voltage and current. 
Determine the winding resistance Rdc by using equation 3-
4 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.008

Where:

Vmdc is the voltage measured by the voltmeter V, and
Imdc is the current measured by the ammeter A.

    (c) As shown in Figure 3.3, separate current and voltage leads 
must be brought to the transformer terminals. (This eliminates the 
errors due to lead and contact resistance.)
    3.3.3 Resistance Meters.
    Resistance meters may be based on voltmeter-ammeter, or 
resistance bridge, or some other operating principle. Any meter used 
to measure a transformer's winding resistance must have 
specifications for resistance range, current range, and ability to 
measure highly inductive resistors that cover the characteristics of 
the transformer being tested. Also the meter's specifications for 
accuracy must meet the applicable criteria of Table 2.1 in section 
2.0.
    3.4 Precautions in Measuring Winding Resistance.
    3.4.1 Required actions.
    The following guidelines must be observed when making resistance 
measurements:
    (a) Use separate current and voltage leads when measuring small 
(< 10 ohms) resistance.
    (b) Use null detectors in bridge circuits, and measuring 
instruments in voltmeter-ammeter circuits, that have sensitivity and 
resolution sufficient to enable observation of at least 0.1 percent 
change in the measured resistance.
    (c) Maintain the dc test current at or below 15 percent of the 
rated winding current.
    (d) Inclusion of a stabilizing resistor Rt (see 
section 3.4.2) will require higher source voltage.
    (e) Disconnect the null detector (if a bridge circuit is used) 
and voltmeter from the circuit before the current is switched off, 
and switch off current by a suitable insulated switch.
    3.4.2 Guideline for Time Constant.
    (a) The following guideline is suggested for the tester as a 
means to facilitate the measurement of resistance in accordance with 
the accuracy requirements of section 2.0:
    (b) The accurate reading of resistance Rdc may be 
facilitated by shortening the time constant. This is done by 
introducing a resistor Rt in series with the winding 
under test in both the bridge and voltmeter-ammeter circuits as 
shown in Figures 3.1 to 3.3. The relationship for the time constant 
is:
[GRAPHIC] [TIFF OMITTED] TR27AP06.009

Where:

Tc is the time constant in seconds,
Ltc is the total magnetizing and leakage inductance of 
the winding under test, in henries, and
Rtc is the total resistance in ohms, consisting of 
Rt in series with the winding resistance Rdc 
and the resistance Rs of the standard resistor in the 
bridge circuit.

    (c) Because Rtc is in the denominator of the 
expression for the time constant, increasing the resistance 
Rtc will decrease the time constant. If the time constant 
in a given test circuit is too long for the resistance readings to 
be stable, then a higher resistance can be substituted for the 
existing Rtc, and successive replacements can be made 
until adequate stability is reached.
    3.5 Conversion of Resistance Measurements.
    (a) Resistance measurements must be corrected, from the 
temperature at which the winding resistance measurements were made, 
to the reference temperature. As specified in these test procedures, 
the reference temperature for liquid-immersed transformers loaded at 
50 percent of the rated load is 55 [deg]C. For medium-voltage, dry-
type transformers loaded at 50 percent of the rated load, and for 
low-voltage, dry-type transformers loaded at 35 percent of the rated 
load, the reference temperature is 75 [deg]C.
    (b) Correct the measured resistance to the resistance at the 
reference temperature using equation 3-6 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.010

Where:

Rts is the resistance at the reference temperature, 
Ts,
Rdc is the measured resistance at temperature, 
Tdc,
Ts is the reference temperature in [deg]C,
Tdc is the temperature at which resistance was measured 
in [deg]C, and
Tk is 234.5 [deg]C for copper or 225 [deg]C for aluminum.

4.0 Loss Measurement

    4.1 General Considerations.
    The efficiency of a transformer is computed from the total 
transformer losses, which are determined from the measured value of 
the no-load loss and load loss power components. Each of these two 
power loss components is measured separately using test sets that 
are identical, except that shorting straps are added for the load-
loss test. The measured quantities will need correction for 
instrumentation losses and may need corrections for known phase 
angle errors in measuring equipment and for the waveform distortion 
in the test voltage. Any power loss not measured at the applicable 
reference temperature must be adjusted to that reference 
temperature. The measured load loss must also be adjusted to a 
specified output loading level if not measured at the specified 
output loading level. Test distribution transformers designed for 
harmonic currents using a sinusoidal waveform (k=1).
    4.2 Measurement of Power Losses.
    4.2.1 No-Load Loss.
    Measure the no-load loss and apply corrections as described in 
section 4.4, using the appropriate test set as described in section 
4.3.
    4.2.2 Load Loss.
    Measure the load loss and apply corrections as described in 
section 4.5, using the appropriate test set as described in section 
4.3.
    4.3 Test Sets.
    (a) The same test set may be used for both the no-load loss and 
load loss measurements provided the range of the test set 
encompasses the test requirements of both tests. Calibrate the test 
set to national standards to meet the tolerances in Table 2.1 in 
section 2.0. In addition, the wattmeter, current measuring system 
and voltage measuring system must be calibrated separately if the 
overall test set calibration is outside the tolerance as specified 
in section 2.0 or the individual phase angle error exceeds the 
values specified in section 4.5.3.
    (b) A test set based on the wattmeter-voltmeter-ammeter 
principle may be used to measure the power loss and the applied 
voltage and current of a transformer where the transformer's test 
current and voltage are within the measurement capability of the 
measuring instruments. Current and voltage transformers, known 
collectively as instrument transformers, or other scaling devices 
such as resistive or capacitive dividers for voltage, may be used in 
the above circumstance, and must be used together with instruments 
to measure current, voltage, or power where the current or voltage 
of the transformer under test exceeds the measurement capability of 
such instruments. Thus, a test set may include a combination of 
measuring instruments and instrument transformers (or other scaling 
devices), so long as the current or voltage of the transformer under 
test does not exceed the measurement capability of any of the 
instruments.
    4.3.1 Single-Phase Test Sets.
    Use these for testing single-phase distribution transformers.
    4.3.1.1 Without Instrument Transformers.
    (a) A single-phase test set without an instrument transformer is 
shown in Figure 4.1.

[[Page 25003]]

[GRAPHIC] [TIFF OMITTED] TR27AP06.011

Where:

W is a wattmeter used to measure Pnm and Plm, 
the no-load and load loss power, respectively,
Vrms is a true root-mean-square (rms) voltmeter used to 
measure Vr(nm) and Vlm, the rms test voltages 
in no-load and load loss measurements, respectively,
Vav is an average sensing voltmeter, calibrated to 
indicate rms voltage for sinusoidal waveforms and used to measure 
Va(nm), the average voltage in no-load loss measurements,
A is an rms ammeter used to measure test current, especially 
Ilm, the load loss current, and
(SC) is a conductor for providing a short-circuit across the output 
windings for the load loss measurements.

    (b) Either the primary or the secondary winding can be connected 
to the test set. However, more compatible voltage and current levels 
for the measuring instruments are available if for no-load loss 
measurements the secondary (low voltage) winding is connected to the 
test set, and for load loss measurements the primary winding is 
connected to the test set. Use the average-sensing voltmeter, 
Vav, only in no-load loss measurements.
    4.3.1.2 With Instrument Transformers.
    A single-phase test set with instrument transformers is shown in 
Figure 4.2. This circuit has the same four measuring instruments as 
that in Figure 4.1. The current and voltage transformers, designated 
as (CT) and (VT), respectively, are added.
[GRAPHIC] [TIFF OMITTED] TR27AP06.012

    4.3.2 Three-Phase Test Sets.
    Use these for testing three-phase distribution transformers. Use 
in a four-wire, three-wattmeter test circuit.
    4.3.2.1 Without Instrument Transformers.
    (a) A three-phase test set without instrument transformers is 
shown in Figure 4.3. This test set is essentially the same circuit 
shown in Figure 4.1 repeated three times, and the instruments are 
individual devices as shown. As an alternative, the entire 
instrumentation system of a three-phase test set without 
transformers may consist of a multi-function analyzer.

[[Page 25004]]

[GRAPHIC] [TIFF OMITTED] TR27AP06.013

    (b) Either group of windings, the primary or the secondary, can 
be connected in wye or delta configuration. If both groups of 
windings are connected in the wye configuration for the no-load 
test, the neutral of the winding connected to the test set must be 
connected to the neutral of the source to provide a return path for 
the neutral current.
    (c) In the no-load loss measurement, the voltage on the winding 
must be measured. Therefore a provision must be made to switch the 
voltmeters for line-to-neutral measurements for wye-connected 
windings and for line-to-line measurements for delta-connected 
windings.
    4.3.2.2 With Instrument Transformers.
    A three-phase test set with instrument transformers is shown in 
Figure 4.4. This test set is essentially the same circuit shown in 
Figure 4.2 repeated three times. Provision must be made to switch 
the voltmeters for line-to-neutral and line-to-line measurements as 
in section 4.3.2.1. The voltage sensors (``coils'') of the 
wattmeters must always be connected in the line-to-neutral 
configuration.
[GRAPHIC] [TIFF OMITTED] TR27AP06.014


[[Page 25005]]


    4.3.2.3 Test Set Neutrals.
    If the power source in the test circuit is wye-connected, ground 
the neutral. If the power source in the test circuit is delta-
connected, use a grounding transformer to obtain neutral and ground 
for the test.
    4.4 No-Load Losses: Measurement and Calculations.
    4.4.1 General Considerations.
    Measurement corrections are permitted but not required for 
instrumentation losses and for losses from auxiliary devices. 
Measurement corrections are required:
    (a) When the waveform of the applied voltage is non-sinusoidal; 
and
    (b) When the core temperature or liquid temperature is outside 
the 20 [deg]C  10 [deg]C range.
    4.4.2 No-Load Loss Test.
    (a) The purpose of the no-load loss test is to measure no-load 
losses at a specified excitation voltage and a specified frequency. 
The no-load loss determination must be based on a sine-wave voltage 
corrected to the reference temperature. Connect either of the 
transformer windings, primary or secondary, to the appropriate test 
set of Figures 4.1 to 4.4, giving consideration to section 
4.4.2(a)(2). Leave the unconnected winding(s) open circuited. Apply 
the rated voltage at rated frequency, as measured by the average-
sensing voltmeter, to the transformer. Take the readings of the 
wattmeter(s) and the average-sensing and true rms voltmeters. 
Observe the following precautions:
    (1) Voltmeter connections. When correcting to a sine-wave basis 
using the average-voltmeter method, the voltmeter connections must 
be such that the waveform applied to the voltmeters is the same as 
the waveform across the energized windings.
    (2) Energized windings. Energize either the high voltage or the 
low voltage winding of the transformer under test.
    (3) Voltage and frequency. The no-load loss test must be 
conducted with rated voltage impressed across the transformer 
terminals using a voltage source at a frequency equal to the rated 
frequency of the transformer under test.
    (b) Adjust the voltage to the specified value as indicated by 
the average-sensing voltmeter. Record the values of rms voltage, rms 
current, electrical power, and average voltage as close to 
simultaneously as possible. For a three-phase transformer, take all 
of the readings on one phase before proceeding to the next, and 
record the average of the three rms voltmeter readings as the rms 
voltage value.

    Note: When the tester uses a power supply that is not 
synchronized with an electric utility grid, such as a dc/ac motor-
generator set, check the frequency and maintain it within 0.5 percent of the rated frequency of the transformer under 
test. A power source that is directly connected to, or synchronized 
with, an electric utility grid need not be monitored for frequency.

    4.4.3 Corrections.
    4.4.3.1 Correction for Instrumentation Losses.
    Measured losses attributable to the voltmeters and wattmeter 
voltage circuit, and to voltage transformers if they are used, may 
be deducted from the total no-load losses measured during testing.
    4.4.3.2 Correction for Non-Sinusoidal Applied Voltage.
    (a) The measured value of no-load loss must be corrected to a 
sinusoidal voltage, except when waveform distortion in the test 
voltage causes the magnitude of the correction to be less than 1 
percent. In such a case, no correction is required.
    (b) To make a correction where the distortion requires a 
correction of 5 percent or less, use equation 4-1. If the distortion 
requires a correction to be greater than 5 percent, improve the test 
voltage and re-test. Repeat until the distortion requires a 
correction of 5 percent or less.
    (c) Determine the no-load losses of the transformer corrected 
for sine-wave basis from the measured value by using equation 4-1 as 
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.015

Where:

Pncl is the no-load loss corrected to a sine-wave basis 
at the temperature (Tnm) at which no-load loss is 
measured,
Pnm is the measured no-load loss at temperature 
Tnm,
P1 is the per unit hysteresis loss,
P2 is the per unit eddy-current loss,
P1 + P2 = 1,
[GRAPHIC] [TIFF OMITTED] TR27AP06.016

Vr(nm) is the test voltage measured by rms voltmeter, and
Va(nm) is the test voltage measured by average-voltage 
voltmeter.
    (d) The two loss components (P1 and P2) 
are assumed equal in value, each assigned a value of 0.5 per unit, 
unless the actual measurement-based values of hysteresis and eddy-
current losses are available (in per unit form), in which case the 
actual measurements apply.
    4.4.3.3 Correction of No-Load Loss to Reference Temperature.
    After correcting the measured no-load loss for waveform 
distortion, correct the loss to the reference temperature of 20 
[deg]C. If the no-load loss measurements were made between 10 [deg]C 
and 30 [deg]C, this correction is not required. If the correction to 
reference temperature is applied, then the core temperature of the 
transformer during no-load loss measurement (Tnm) must be 
determined within  10 [deg]C of the true average core 
temperature. Correct the no-load loss to the reference temperature 
by using equation 4-2 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.017

Where:

Pnc is the no-load losses corrected for waveform 
distortion and then to the reference temperature of 20 [deg]C,
Pnc1 is the no-load losses, corrected for waveform 
distortion, at temperature Tnm,
Tnm is the core temperature during the measurement of no-
load losses, and
Tnr is the reference temperature, 20 [deg]C.

    4.5 Load Losses: Measurement and Calculations.
    4.5.1 General Considerations.
    (a) The load losses of a transformer are those losses incident 
to a specified load carried by the transformer. Load losses consist 
of ohmic loss in the windings due to the load current and stray 
losses due to the eddy currents induced by the leakage flux in the 
windings, core clamps, magnetic shields, tank walls, and other 
conducting parts. The ohmic loss of a transformer varies directly 
with temperature, whereas the stray losses vary inversely with 
temperature.
    (b) For a transformer with a tap changer, conduct the test at 
the rated current and rated-voltage tap position. For a transformer 
that has a configuration of windings which allows for more than one 
nominal rated voltage, determine its load losses either in the 
winding configuration in which the highest losses occur or in each 
winding configuration in which the transformer can operate.
    4.5.2 Tests for Measuring Load Losses.
    (a) Connect the transformer with either the high-voltage or low-
voltage windings to the appropriate test set. Then short-circuit the 
winding that was not connected to the test set. Apply a voltage at 
the rated frequency (of the transformer under test) to the connected 
windings to produce the rated current in the transformer. Take the 
readings of the wattmeter(s), the ammeters(s), and rms voltmeter(s).
    (b) Regardless of the test set selected, the following 
preparatory requirements must be satisfied for accurate test 
results:
    (1) Determine the temperature of the windings using the 
applicable method in section 3.2.1 or section 3.2.2.
    (2) The conductors used to short-circuit the windings must have 
a cross-sectional area equal to, or greater than, the corresponding 
transformer leads, or, if the tester uses a different method to 
short-circuit the windings, the losses in the short-circuiting 
conductor assembly must be less than 10 percent of the transformer's 
load losses.
    (3) When the tester uses a power supply that is not synchronized 
with an electric utility grid, such as a dc/ac motor-generator set, 
follow the provisions of the ``Note'' in section 4.4.2.
    4.5.3 Corrections.
    4.5.3.1 Correction for Losses from Instrumentation and Auxiliary 
Devices.
    4.5.3.1.1 Instrumentation Losses.
    Measured losses attributable to the voltmeters, wattmeter 
voltage circuit and short-circuiting conductor (SC), and to the 
voltage transformers if they are used, may be deducted from the 
total load losses measured during testing.
    4.5.3.1.2 Losses from Auxiliary Devices.
    Measured losses attributable to auxiliary devices (e.g., circuit 
breakers, fuses, switches) installed in the transformer, if any, 
that are not part of the winding and core assembly, may be excluded 
from load losses measured during testing. To exclude these losses, 
either (1) measure transformer losses without the auxiliary devices 
by removing or by-passing them, or (2) measure transformer losses 
with the auxiliary devices connected, determine the losses 
associated with the

[[Page 25006]]

auxiliary devices, and deduct these losses from the load losses 
measured during testing.
    4.5.3.2 Correction for Phase Angle Errors.
    (a) Corrections for phase angle errors are not required if the 
instrumentation is calibrated over the entire range of power factors 
and phase angle errors. Otherwise, determine whether to correct for 
phase angle errors from the magnitude of the normalized per unit 
correction, [beta]n, obtained by using equation 4-3 as 
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.018

    (b) The correction must be applied if [beta]n is 
outside the limits of 0.01. If [beta]n is 
within the limits of 0.01, the correction is permitted 
but not required.
    (c) If the correction for phase angle errors is to be applied, 
first examine the total system phase angle ([beta]w - 
[beta]v + [beta]c). Where the total system 
phase angle is equal to or less than 12 milliradians 
(41 minutes), use either equation 4-4 or 4-5 to correct 
the measured load loss power for phase angle errors, and where the 
total system phase angle exceeds 12 milliradians (41 minutes) use equation 4-5, as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.019

[GRAPHIC] [TIFF OMITTED] TR27AP06.020

    (d) The symbols in this section (4.5.3.2) have the following 
meanings:

Plc1 is the corrected wattmeter reading for phase angle 
errors,
Plm is the actual wattmeter reading,
Vlm is the measured voltage at the transformer winding,
Ilm is the measured rms current in the transformer 
winding,
[GRAPHIC] [TIFF OMITTED] TR27AP06.021

is the measured phase angle between Vlm and 
Ilm,

[beta]w is the phase angle error (in radians) of the 
wattmeter; the error is positive if the phase angle between the 
voltage and current phasors as sensed by the wattmeter is smaller 
than the true phase angle, thus effectively increasing the measured 
power,
[beta]v is the phase angle error (in radians) of the 
voltage transformer; the error is positive if the secondary voltage 
leads the primary voltage, and
[beta]c is the phase angle error (in radians) of the 
current transformer; the error is positive if the secondary current 
leads the primary current.

    (e) The instrumentation phase angle errors used in the 
correction equations must be specific for the test conditions 
involved.
    4.5.3.3 Temperature Correction of Load Loss.
    (a) When the measurement of load loss is made at a temperature 
Tlm that is different from the reference temperature, use 
the procedure summarized in the equations 4-6 to 4-10 to correct the 
measured load loss to the reference temperature. The symbols used in 
these equations are defined at the end of this section.
    (b) Calculate the ohmic loss (Pe) by using equation 
4-6 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.022

    (c) Obtain the stray loss by subtracting the calculated ohmic 
loss from the measured load loss, by using equation 4-7 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.023

    (d) Correct the ohmic and stray losses to the reference 
temperature for the load loss by using equations 4-8 and 4-9, 
respectively, as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.024

[GRAPHIC] [TIFF OMITTED] TR27AP06.025

    (e) Add the ohmic and stray losses, corrected to the reference 
temperature, to give the load loss, Plc2, at the 
reference temperature, by using equation 4-10 as follows:

[[Page 25007]]

[GRAPHIC] [TIFF OMITTED] TR27AP06.026

    (f) The symbols in this section (4.5.3.3) have the following 
meanings:

Ilm(p) is the primary current in amperes,
Ilm(s) is the secondary current in amperes,
Pe is the ohmic loss in the transformer in watts at the 
temperature Tlm,
Pe(p) is the ohmic loss in watts in the primary winding 
at the temperature Tlm,
Pe(s) is the ohmic loss in watts in the secondary winding 
at the temperature Tlm,
 Per is the ohmic loss in watts corrected to the 
reference temperature,
Plc1 is the measured load loss in watts, corrected for 
phase angle error, at the temperature Tlm,
Plc2 is the load loss at the reference temperature,
Ps is the stray loss in watts at the temperature 
Tlm,
Psr is the stray loss in watts corrected to the reference 
temperature,
Rdc(p) is the measured dc primary winding resistance in 
ohms,
Rdc(s) is the measured dc secondary winding resistance in 
ohms,
Tk is the critical temperature in degrees Celsius for the 
material of the transformer windings. Where copper is used in both 
primary and secondary windings, Tk is 234.5 [deg]C; where 
aluminum is used in both primary and secondary windings, 
Tk is 225 [deg]C; where both copper and aluminum are used 
in the same transformer, the value of 229 [deg]C is used for 
Tk,
Tk(p) is the critical temperature in degrees Celsius for 
the material of the primary winding: 234.5 [deg]C if copper and 225 
[deg]C if aluminum,
Tk(s) is the critical temperature in degrees Celsius for 
the material of the secondary winding: 234.5 [deg]C if copper and 
225 [deg]C if aluminum,
Tlm is the temperature in degrees Celsius at which the 
load loss is measured,
Tlr is the reference temperature for the load loss in 
degrees Celsius,
Tdc is the temperature in degrees Celsius at which the 
resistance values are measured, and

N1/N2 is the ratio of the number of turns in 
the primary winding (N1) to the number of turns in the 
secondary winding (N2); for a primary winding with taps, 
N1 is the number of turns used when the voltage applied 
to the primary winding is the rated primary voltage.

5.0 Determining the Efficiency Value of the Transformer

    This section presents the equations to use in determining the 
efficiency value of the transformer at the required reference 
conditions and at the specified loading level. The details of 
measurements are described in sections 3.0 and 4.0. For a 
transformer that has a configuration of windings which allows for 
more than one nominal rated voltage, determine its efficiency either 
at the voltage at which the highest losses occur or at each voltage 
at which the transformer is rated to operate.
    5.1 Output Loading Level Adjustment.
    If the output loading level for energy efficiency is different 
from the level at which the load loss power measurements were made, 
then adjust the corrected load loss power, Plc2, by using 
equation 5-1 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.028

Where:

Plc is the adjusted load loss power to the specified 
energy efficiency load level,
Plc2 is as calculated in section 4.5.3.3,
Por is the rated transformer apparent power (name plate),
Pos is the specified energy efficiency load level, where 
, and Pos = PorL2, and
L is the per unit load level, e.g., if the load level is 50 percent 
then ``L'' will be 0.5.
    5.2 Total Loss Power Calculation.

    Calculate the corrected total loss power by using equation 5-2 
as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.029

Where:

Pts is the corrected total loss power adjusted for the 
transformer output loading specified by the standard,
Pnc is as calculated in section 4.4.3.3, and
Plc is as calculated in section 5.1.

    5.3 Energy Efficiency Calculation.
    Calculate efficiency ([eta]) in percent at specified energy 
efficiency load level, Pos, by using equation 5-3 as 
follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.030

Where:

Pos is as described and calculated in section 5.1, and
Pts is as described and calculated in section 5.2.
    5.4 Significant Figures in Power Loss and Efficiency Data.
    In measured and calculated data, retain enough significant 
figures to provide at least 1 percent resolution in power loss data 
and 0.01 percent resolution in efficiency data.

6.0 Test Equipment Calibration and Certification

    Maintain and calibrate test equipment and measuring instruments, 
maintain calibration records, and perform other test and measurement 
quality assurance procedures according to the following sections. 
The calibration of the test set must confirm the accuracy of the 
test set to that specified in section 2.0, Table 2.1.
    6.1 Test Equipment.
    The party performing the tests shall control, calibrate and 
maintain measuring and test equipment, whether or not it owns the 
equipment, has the equipment on loan, or the equipment is provided 
by another party. Equipment shall be used in a manner which assures 
that measurement uncertainty is known and is consistent with the 
required measurement capability.
    6.2 Calibration and Certification.
    The party performing the tests must:
    (a) Identify the measurements to be made, the accuracy required 
(section 2.0) and select the appropriate measurement and test 
equipment;
    (b) At prescribed intervals, or prior to use, identify, check 
and calibrate, if needed, all measuring and test equipment systems 
or devices that affect test accuracy, against certified equipment 
having a known valid relationship to nationally recognized 
standards; where no such standards exist, the basis used for 
calibration must be documented;
    (c) Establish, document and maintain calibration procedures, 
including details of equipment type, identification number, 
location, frequency of checks, check method, acceptance criteria and 
action to be taken when results are unsatisfactory;
    (d) Ensure that the measuring and test equipment is capable of 
the accuracy and precision necessary, taking into account the 
voltage, current and power factor of the transformer under test;
    (e) Identify measuring and test equipment with a suitable 
indicator or approved identification record to show the calibration 
status;
    (f) Maintain calibration records for measuring and test 
equipment;

[[Page 25008]]

    (g) Assess and document the validity of previous test results 
when measuring and test equipment is found to be out of calibration;
    (h) Ensure that the environmental conditions are suitable for 
the calibrations, measurements and tests being carried out;
    (i) Ensure that the handling, preservation and storage of 
measuring and test equipment is such that the accuracy and fitness 
for use is maintained; and
    (j) Safeguard measuring and test facilities, including both test 
hardware and test software, from adjustments which would invalidate 
the calibration setting.

Appendix B to Subpart K of Part 431--Sampling Plan for Enforcement 
Testing

    Step 1. The number of units in the sample (m1) shall 
be in accordance with Sec. Sec.  431.198(a)(4), 431.198(a)(5), 
431.198(a)(6) and 431.198(a)(7) and shall not be greater than 
twenty. The number of tests in the first sample (n1) 
shall be in accordance with Sec.  431.198(a)(8) and shall be not 
fewer than four.
    Step 2. Compute the mean (Xi) of the measured energy 
performance of the n1 tests in the first sample by using 
equation 1 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.031

where Xi is the measured efficiency of test i.

    Step 3. Compute the sample standard deviation (S1) of 
the measured efficiency of the n1 tests in the first 
sample by using equation 2 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.032

    Step 4. Compute the standard error (SE(X1)) of the 
mean efficiency of the first sample by using equation 3 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.033

    Step 5. Compute the sample size discount (SSD(m1)) by 
using equation 4 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.034

where m1 is the number of units in the sample, and RE is 
the applicable EPCA efficiency when the test is to determine 
compliance with the applicable statutory standard, or is the labeled 
efficiency when the test is to determine compliance with the labeled 
efficiency value.

    Step 6. Compute the lower control limit (LCL1) for 
the mean of the first sample by using equation 5 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.035

where t is the 2.5th percentile of a t-distribution for a sample 
size of n1, which yields a 97.5 percent confidence level 
for a one-tailed t-test.
    Step 7. Compare the mean of the first sample (X1) 
with the lower control limit (LCL1) to determine one of 
the following:
    (i) If the mean of the first sample is below the lower control 
limit, then the basic model is in non-compliance and testing is at 
an end.
    (ii) If the mean is equal to or greater than the lower control 
limit, no final determination of compliance or non-compliance can be 
made; proceed to Step 8.
    Step 8. Determine the recommended sample size (n) by using 
equation 6 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.036

 where S1 and t have the values used in Steps 3 and 6, 
respectively. The factor
[GRAPHIC] [TIFF OMITTED] TR27AP06.037

is based on an 8-percent tolerance in the total power loss.

    Given the value of n, determine one of the following:
    (i) If the value of n is less than or equal to n1 and 
if the mean energy efficiency of the first sample (X1) is 
equal to or greater than the lower control limit (LCL1), 
the basic model is in compliance and testing is at an end.
    (ii) If the value of n is greater than n1, and no 
additional units are available for testing, testing is at an end and 
the basic model is in non-compliance. If the value of n is greater 
than n1, and additional units are available for testing, 
select a second sample n2. The size of the n2 
sample is determined to be the smallest integer equal to or greater 
than the difference n-n1. If the value of n2 
so calculated is greater than 20-n1, set n2 
equal to 20-n1.
    Step 9. After testing the n2 sample, compute the 
combined mean (X2) of the measured energy performance of 
the n1 and n2 tests of the combined first and 
second samples by using equation 7 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.038

    Step 10. Compute the standard error (SE(X2)) of the 
mean efficiency of the n1 and n2 tests in the 
combined first and second samples by using equation 8 as follows:
[GRAPHIC] [TIFF OMITTED] TR27AP06.039

(Note that S1 is the value obtained above in Step 3.)

    Step 11. Set the lower control limit (LCL2) to,
    [GRAPHIC] [TIFF OMITTED] TR27AP06.040
    
where t has the value obtained in Step 5 and SSD(m1) is 
sample size discount from Step 5. Compare the combined sample mean 
(X2) to the lower control limit (LCL2) to find 
one of the following:

    (i) If the mean of the combined sample (X2) is less 
than the lower control limit (LCL2), the basic model is 
in non-compliance and testing is at an end.
    (ii) If the mean of the combined sample (X2) is equal 
to or greater than the lower control limit (LCL2), the 
basic model is in compliance and testing is at an end.

Manufacturer-Option Testing

    If a determination of non-compliance is made in Steps 6, 7 or 
11, above, the manufacturer may request that additional testing be 
conducted, in accordance with the following procedures.
    Step A. The manufacturer requests that an additional number, 
n3, of units be tested, with n3 chosen such 
that n1+n2+n3 does not exceed 20.
    Step B. Compute the mean efficiency, standard error, and lower 
control limit of the new combined sample in accordance with the 
procedures prescribed in Steps 8, 9, and 10, above.
    Step C. Compare the mean performance of the new combined sample 
to the lower control limit (LCL2) to determine one of the 
following:
    (a) If the new combined sample mean is equal to or greater than 
the lower control limit, the basic model is in compliance and 
testing is at an end.
    (b) If the new combined sample mean is less than the lower 
control limit and the value of 
n1+n2+n3 is less than 20, the 
manufacturer may request that additional units be tested. The total 
of all units tested may not exceed 20. Steps A, B,and C are then 
repeated.
    (c) Otherwise, the basic model is determined to be in non-
compliance.
[FR Doc. 06-3165 Filed 4-26-06; 8:45 am]
BILLING CODE 6450-01-P