12A-i

APPENDIX 12A. MANUFACTURER IMPACT ANALYSIS INTERVIEW GUIDE

TABLE OF CONTENTS

A. ENGINEERING ANALYSIS..............................................................................................1

B. MARKET QUESTIONNAIRE .........................................................................................24

C. MANUFACTURER IMPACTS ........................................................................................25
12A-1

APPENDIX 12A. MANUFACTURER IMPACT ANALYSIS INTERVIEW GUIDE

A. ENGINEERING ANALYSIS

The purpose of the engineering analysis is to estimate the relationship between the 

manufacturer’s selling price of a transformer and its corresponding efficiency rating. This 

relationship serves as the basis for the subsequent cost-benefit calculations for individual 

consumers, manufacturers, and the nation.

The engineering analysis considers 13 design lines of distribution transformers that group 

together kVA ratings based on similar principles of design and construction. The 13 design lines 

differentiate the distribution transformers by insulation type (liquid-immersed or dry-type), 

number of phases (single or three), the primary voltage (low-voltage or medium-voltage for drytypes) and primary insulation levels (with three different BILs for medium-voltage dry-types).

DOE then selected one unit with a given kVA rating from each of the engineering design lines 

for study in the engineering analysis. DOE will then extrapolate the results from these 

representative units to the other kVA ratings in its engineering design line. The design lines and 

representative units chosen for this engineering analysis are the same ones used in the October 

2007 Final Rule for distribution transformers and the 2004 ANOPR (in the case of low-voltage 

dry-types).1

A.1 Design Options

DOE considers different design options to increase transformer efficiency in order to analyze the 

relationship between a manufacturer’s selling price and the efficiency of a distribution 

transformer. Measures taken to reduce no-load losses typically increase load losses, and vice 

versa. The following table presents design options that DOE is currently considering and their 

typical impacts on transformer efficiency and cost:

 

1 These publications are available online: 

http://www1.eere.energy.gov/buildings/appliance_standards/commercial/distribution_transformers.html.
12A-2

No-load 

losses

Load

losses

Cost 

impact

To decrease no-load losses

Use lower-loss core materials Lower No change* Higher

Decrease flux density by:

(a) Increasing core cross-sectional area (CSA)

(b) Decreasing volts per turn

Lower

Lower

Higher

Higher

Higher

Higher

Decrease flux path length by decreasing conductor CSA Lower Higher Lower

Use 120 ̊ symmetry in three-phase cores** Lower Lower TBD

To decrease load losses

Use lower-loss conductor material No change Lower Higher

Decrease current density by increasing conductor CSA Higher Lower Higher

Decrease current path length by:

(a) Decreasing core CSA

(b) Increasing volts per turn

Higher

Higher

Lower

Lower

Lower

Lower

Use 120 ̊ symmetry in three-phase cores** Lower Lower TBD

* Amorphous-core materials would result in higher load losses.

** First commercialized by Hexaformer AB of Sweden. This is discussed in more detail in the following sections.

A.1-1 Design Options: Please comment on the design options listed above. Are any of the 

design options impractical to manufacture? Are there other design options that DOE 

should consider to improve transformer efficiency?

Design Options Screened Out

During the previous rulemaking on distribution transformers, DOE screened out several design 

options based on: 1) technological feasibility, 2) practicability to manufacture, install, and 

service, 3) adverse impacts on product utility or product availability, and 4) adverse impacts on 

health or safety. The following table lists the design options that DOE screened out in the 

previous rulemaking on distribution transformers. DOE believes that each of these design 

options should be excluded from the current rulemaking.

Design Option Excluded Screening Criteria

Silver as a Conductor Material Practicability to manufacture, install, and service

High-Temperature Superconductors Technological feasibility; 

Practicability to manufacture, install, and service

Amorphous Core Material in Stacked 

Core Configuration

Technological feasibility; 

Practicability to manufacture, install, and service

Carbon Composite Materials for Heat 

Removal Technological feasibility

High-Temperature Insulating Material Technological feasibility

Solid-State (Power Electronics) 

Technology Technological feasibility
12A-3

A.1-2 Design Options Screened Out: Should any of these design options be considered in the 

current rulemaking? Are there any additional design options that should be excluded 

from the analysis that are not listed in the table above?

Less-Flammable Liquid-Immersed Transformers

In the 2007 final rule, DOE determined that less-flammable liquid-immersed (LFLI) 

transformers (i.e., those with fluids of a higher flash point than mineral oil) should be analyzed in 

the same product class as liquid-immersed transformers that use mineral oil. DOE concluded 

that the design of a transformer (i.e., dry-type or liquid-immersed) was a performance-related 

feature that affects the energy efficiency of the equipment, and thus dry-type and liquidimmersed were analyzed as different product classes. Furthermore, DOE found that LFLI 

transformers could meet the same efficiency levels as any of the liquid-immersed transformers 

that use mineral oil. As a result, DOE did not separately analyze LFLI transformers, but relied 

on the analysis for the mineral oil liquid-immersed transformers. 

A.1-3 Less-Flammable Liquid-Immersed: Please comment on this decision and whether 

LFLI transformers should be analyzed differently in this rulemaking. Are there any 

distribution transformer applications that require a dry-type transformer (i.e., where an

LFLI transformer would not be suitable)? Can LFLI transformers achieve the same 

maximum efficiency rating as liquid-immersed transformers that use mineral oil? Why 

or why not?

Symmetric Core Designs

DOE is aware of a design concept for three-phase transformers that utilizes 120 ̊ symmetry and 

continuously wound cores. These symmetric core designs, such as the Hexaformer®design 

created by Hexaformer AB, have several benefits over a traditional transformer design, 

including: lower losses, lower inrush current, lower weight, and lower external magnetic field. 

Chalmers University in Sweden has conducted a study on symmetric core designs and provided 

an overview of the design and insights into modeling the technology.2 DOE understands that 

symmetric core designs represent a significant shift from current industry practice for 

manufacturing distribution transformers.

A.1-4 Symmetric Core Designs: Please comment on any experience your company has with 

symmetric core designs. Would any barriers exist to implementing this type of 

technology on a large scale?

 

2 Available online: http://www.hexaformer.com/ExternaDokument/chalmers_report1.pdf.
12A-4

A.2 Test Procedure

DOE published its test procedure for distribution transformers in 2006. Since then, 

manufacturers and other stakeholders have raised issues on several points in the test procedure.

Dual/Multiple-Voltage Winding Configurations

The test procedure states that 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. This provision was implemented to address dual- or multiple-voltage 

transformers, which have different losses for each of their winding configurations (in series or in 

parallel). Some manufacturers have stated that this requirement effectively raised the previous 

efficiency standards published by DOE in 2007. This is because the standards were set based on 

analysis using the series winding configuration at the higher voltage level, which tends to be 

more efficient.

A.2-1 Dual/Multiple-Voltage Winding Configurations: Has this requirement made it more 

difficult to meet the current efficiency standards? Approximately what percentage of 

distribution transformers are operated in a parallel winding configuration at the lower 

voltage level? What is the typical difference in losses between the different winding 

configurations? Do efficiency improvements in the series winding configuration always 

result in efficiency improvements in the parallel winding configuration?

Reference Loading and Peak Loading

The test procedure specifies that losses be measured at 50 percent of the rated load for liquidimmersed and medium-voltage dry-type transformers, and 35 percent of the rated load for lowvoltage dry-type transformers. These load factors are based on root-mean-square loading data 

for the nation. Some manufacturers have stated that different load factors should be analyzed 

based on load growth projected from electric vehicles and smart grid initiatives. Additionally, 

some manufacturers have stated that DOE should analyze a peak load scenario.

A.2-2 Reference Loading and Peak Loading: Please comment on the appropriateness of the 

50 percent and 35 percent load factors used in the test procedure. Please provide any data 

available on projected load growth, including timeline. Do manufacturers optimize 

transformer designs at these load factors or other load factors?

A.2-3 Other Issues with the Test Procedure: Are there any other issues or concerns with the 

current test procedure that DOE should be aware of?
12A-5

A.3 Liquid-Immersed Engineering Analysis

Design Lines and Representative Units

The following table represents the five design lines and representative units DOE is analyzing for 

liquid-immersed distribution transformers. Design Line # of Phases KVA Range Primary BIL

Primary Taps, 

Full Capacity

Representative Unit for Design 

Lines

1 1 10-167 30-150 

kV

Four 2.5% taps, 

two above and two 

below nominal

50kVA, 65 ̊C, single-phase, 60Hz, 

14400V primary, 240/120V 

secondary, rectangular tank

2 1 10-167 30-150 

kV

Four 2.5% taps, 

two above and two 

below nominal

25kVA, 65 ̊C, single-phase, 60Hz, 

14400V primary, 120/240V 

secondary, round tank

3 1 250-833 30-150 

kV

Four 2.5% taps, 

two above and two 

below nominal

500kVA, 65 ̊C, single-phase, 

60Hz, 14400V primary, 277V 

secondary

4 3 15-500 30-150

kV

Four 2.5% taps, 

two above and two 

below nominal

150kVA, 65 ̊C, three-phase, 60Hz, 

12470Y/7200V primary, 

208Y/120V secondary

5 3 750-2500 95-150 

kV

Four 2.5% taps, 

two above and two 

below nominal

1500kVA, 65 ̊C, three-phase, 

60Hz, 24940GrdY/14400V 

primary, 408Y/277V secondary

A.3-1 Liquid-Immersed Design Lines: Please comment on the appropriateness of the design 

lines and representative units chosen for the liquid-immersed distribution transformers. 

What percentage of total shipments does each representative unit constitute within its 

design line? Should any other representative units be selected?

Design Option Combinations

For each representative unit, DOE is considering several design option combinations that 

characterize a range of efficiency levels for distribution transformers. This range spans from the 

efficiency level requirements set forth in DOE’s 2007 final rule to the maximum technologically 

available level. While many combinations of design options are possible to achieve these 

efficiency levels, DOE tried to select the most common designs in the industry.

A.3-2 Previously Unanalyzed Core Steels: DOE is examining some new core steels that were 

not considered in the previous rulemaking. These include an M2 and M3 steel with Lite 
12A-6

Carlite insulation and an M5 core steel. Are there any manufacturing or engineering 

issues that DOE should be aware of when analyzing these core steels? Does your 

company produce distribution transformers using these core steels?

A.3-3 Amorphous Cores: DOE is examining amorphous cores as a design option for the 

liquid-immersed design lines. Each of these amorphous designs utilizes a distributed gap 

wound core, which DOE assumes is purchased from an amorphous core manufacturer. 

Does your company currently manufacture liquid-immersed transformers with an 

amorphous core? If so, for what kVA range are amorphous cores used? Does your 

company purchase amorphous ribbon or a finished amorphous core? If a finished 

amorphous core is purchased, who supplies the cores for your company? Are there any 

design issues associated with using an amorphous core in a liquid-immersed transformer?

A.3-4 Liquid-Immersed Design Option Combinations: In the tables below, please comment 

on the appropriateness of the design option combinations selected to characterize the 

range of possible efficiencies for each representative unit. Are these design option 

combinations similar to transformers that your company sells? Are there any additional 

designs that should be considered?
12A-7

Design Line 1: 50kVA, 65 ̊ C, single-phase, 60 Hz, 14400V primary, 240/120V secondary, 

rectangular tank

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M5 DG Core Cu Al Shell

2 M4 DG Core Cu Al Shell

3 M3 DG Core Cu Al Shell

4

M3 – Lite 

Carlite DG Core Cu Al Shell

5 M2 DG Core Cu Al Shell

6

M2 – Lite 

Carlite DG Core Cu Al Shell

7 ZDMH DG Core Cu Cu Shell

8

SA1 -

Amorphous DG Core Cu Cu Shell

Design Line 2: 25kVA, 65 ̊ C, single-phase, 60 Hz, 14400V primary, 120/240V secondary, 

round tank

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M6 DG Core Cu Al Shell

2 M5 DG Core Cu Al Shell

3 M4 DG Core Cu Al Shell

4 M3 DG Core Cu Al Shell

5

M3 – Lite 

Carlite DG Core Cu Al Shell

6 M2 DG Core Cu Al Shell

7

M2 – Lite 

Carlite DG Core Cu Al Shell

8 ZDMH DG Core Cu Cu Shell

9

SA1 -

Amorphous DG Core Cu Cu Core
12A-8

Design Line 3: 500kVA, 65 ̊ C, single-phase, 60 Hz, 14400V primary, 277V secondary

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M5 DG Core Cu Al Shell

2 M4 DG Core Cu Al Shell

3 M3 DG Core Cu Al Shell

4

M3 – Lite 

Carlite DG Core Cu Al Shell

5 M2 DG Core Cu Al Shell

6

M2 – Lite 

Carlite DG Core Cu Al Shell

7 ZDMH DG Core Cu Cu Shell

8

SA1 -

Amorphous DG Core Cu Cu Shell

Design Line 4: 150kVA, 65 ̊ C, three-phase, 60 Hz, 12470Y/7200V primary, 208Y/120V 

secondary

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M5 DG Core Cu Al 5 – Legged

2 M4 DG Core Cu Al 5 – Legged

3 M3 DG Core Cu Al 5 – Legged

4

M3 – Lite 

Carlite DG Core Cu Al 5 – Legged

5 M2 DG Core Cu Al 5 – Legged

6

M2 – Lite 

Carlite DG Core Cu Al 5 – Legged

7 ZDMH DG Core Cu Cu 5 – Legged

8

SA1 -

Amorphous DG Core Cu Cu 5 – Legged
12A-9

Design Line 5: 1500kVA, 65 ̊ C, three-phase, 60 Hz, 24940GrdY/14400V primary, 408Y/277V 

secondary

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M5 DG Core Cu Al 5 – Legged

2 M4 DG Core Cu Al 5 – Legged

3 M3 DG Core Cu Al 5 – Legged

4

M3 – Lite 

Carlite DG Core Cu Al 5 – Legged

5 M2 DG Core Cu Al 5 – Legged

6

M2 – Lite 

Carlite DG Core Cu Al 5 – Legged

7 ZDMH DG Core Cu Cu 5 – Legged

8

SA1 -

Amorphous DG Core Cu Cu 5 – Legged
12A-10

A.4 Low-Voltage Dry-Type Engineering Analysis

Design Lines and Representative Units

The following table represents the three design lines and representative units DOE is analyzing 

for low-voltage dry-type distribution transformers. Design Line # of Phases KVA Range Primary BIL

Primary Taps, 

Full Capacity

Representative Unit for Design 

Lines

6 1 15-333 10 kV Universal*

25kVA, 150 ̊C, single-phase, 

60Hz, 480V primary, 120Y/240V 

secondary, 10kV BIL

7 3 15-150 10 kV Universal*

75kVA, 150 ̊C, three-phase, 

60Hz, 480V primary, 208Y/120V 

secondary, 10kV BIL

8 3 225-1000 10 kV Universal*

300kVA, 150 ̊C, three-phase, 

60Hz, 480V Delta primary, 

208Y/120V secondary, 10kV BIL

* Universal Taps = 2 above and 4 below 2.5%

A.4-1 Low-Voltage Dry-Type Design Lines: Please comment on the appropriateness of the 

design lines and representative units chosen for the low-voltage dry-type distribution 

transformers. What percentage of total shipments does each representative unit constitute 

within its design line? Should any other representative units be selected?

Design Option Combinations

For each representative unit, DOE is considering several design option combinations that 

characterize a range of efficiency levels for distribution transformers. This range spans from the 

efficiency level requirements set forth in the Energy Policy Act of 2005 to the maximum 

technologically available level. While many combinations of design options are possible to 

achieve these efficiency levels, DOE tried to select the most common designs in the industry. 

A.4-2 Previously Unanalyzed Core Steels: DOE is examining some new core steels that were 

not considered in the previous rulemaking. These include an M12 and M2 core steel. 

Are there any manufacturing or engineering issues that DOE should be aware of when 

analyzing these core steels? Does your company produce distribution transformers using 

these core steels?
12A-11

A.4-3 Amorphous Cores: DOE is examining amorphous cores as a design option for the lowvoltage dry-type design lines. Each of these amorphous designs utilizes a distributed gap 

wound core, which DOE assumes is purchased from an amorphous core manufacturer. 

Does your company currently manufacture low-voltage dry-type transformers with an 

amorphous core? If so, for what kVA range are amorphous cores used? Does your 

company purchase amorphous ribbon or a finished amorphous core? If a finished 

amorphous core is purchased, who supplies the cores for your company? Are there any 

design issues associated with using an amorphous core in a low-voltage dry-type

transformer?

A.4-4 Core Type: DOE plans to examine designs for low-voltage dry-type transformers using 

either a stacked butt-lap core or a stacked full-miter core. What core types does your 

company use in its low-voltage dry-type transformer designs? Are there any 

manufacturing issues that DOE should be aware of when considering the different core 

types?

A.4-5 Low-Voltage Dry-Type Design Option Combinations: In the tables below, please 

comment on the appropriateness of the design option combinations selected to 

characterize the range of possible efficiencies for each representative unit. Are these 

design option combinations similar to transformers that your company sells? Are there 

any additional designs that should be considered?
12A-12

Design Line 6: 25kVA, 150 ̊ C, single-phase, 60 Hz, 480V primary, 120Y/240V secondary, 

10kV BIL

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M12 StackedButt-Lap Al Al Core

2 M6 StackedButt-Lap Al Al Core

3 M5 StackedButt-Lap Al Al Core

4 M4 StackedButt-Lap Al Al Core

5 M3 StackedButt-Lap Al Al Core

6 M3 StackedButt-Lap Al Al Shell

7 H-0 DR StackedButt-Lap Cu Cu Core

8

SA1 -

Amorphous DG Core Cu Cu Core

Design Line 7: 75kVA, 150 ̊ C, three-phase, 60 Hz, 480V primary, 208Y/120V secondary, 

10kV BIL

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M12 StackedButt-Lap Al Al 3 – Legged

2 M6 Stacked 

Full Miter Al Al 3 – Legged

3 M6 Stacked 

Full Miter Cu Cu 3 – Legged

4 M4 Stacked 

Full Miter Al Al 3 – Legged

5 M3 Stacked

Full Miter Al Al 3 – Legged

6 H-0 DR Stacked 

Full Miter Cu Cu 3 – Legged

7

SA1 -

Amorphous DG Core Cu Cu 3 – Legged

8

SA1 -

Amorphous DG Core Cu Cu 5 – Legged
12A-13

Design Line 8: 300kVA, 150 ̊ C, three-phase, 60 Hz, 480V Delta primary, 208Y/120V 

secondary, 10kV BIL

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M6 StackedButt-Lap Al Cu 3 – Legged

2 M6 Stacked 

Full Miter Al Cu 3 – Legged

3 M5 StackedButt-Lap Al Cu 3 – Legged

4 M4 StackedButt-Lap Cu Cu 3 – Legged

5 M4 Stacked 

Full Miter Cu Cu 3 – Legged

6 M3 Stacked 

Full Miter Cu Al 3 – Legged

7 H-0 DR Stacked 

Full Miter Al Cu 3 – Legged

8

SA1 -

Amorphous DG Core Cu Cu 3 – Legged

9

SA1 -

Amorphous DG Core Cu Cu 5 – Legged
12A-14

A.5 Medium-Voltage Dry-Type Engineering Analysis

Design Lines and Representative Units

The following table represents the five design lines and representative units DOE is analyzing for 

medium-voltage dry-type distribution transformers. Design Line # of Phases KVA Range Primary BIL

Primary Taps, 

Full Capacity

Representative Unit for Design 

Lines

9 3 15-500 20-45 

kV

Four 2.5% taps, 

two above and two 

below nominal

300kVA, 150 ̊C, three-phase, 60Hz, 

4160V Delta primary, 480Y/277V 

secondary, 45kV BIL

10 3 750-2500 20-45 

kV

Four 2.5% taps, 

two above and two 

below nominal

1500kVA, 150 ̊C, three-phase, 

60Hz, 4160V primary, 480Y/277V 

secondary, 45kV BIL

11 3 15-500 46-95 

kV

Four 2.5% taps, 

two above and two 

below nominal

300kVA, 150 ̊C, three-phase, 60Hz, 

12470V primary, 480Y/277V 

secondary, 95kV BIL

12 3 750-2500 46-95 

kV

Four 2.5% taps, 

two above and two 

below nominal

1500kVA, 150 ̊C, three-phase, 

60Hz, 12470V primary, 480Y/277V 

secondary, 95kV BIL

13 3 225-2500 96-150 

kV

Four 2.5% taps, 

two above and two 

below nominal

2000kVA, 150 ̊C, three-phase, 

60Hz, 12470V primary, 480Y/277V 

secondary, 125kV BIL

A.5-1 Medium-Voltage Dry-Type Design Lines: Please comment on the appropriateness of 

the design lines and representative units chosen for the medium-voltage dry-type

distribution transformers. What percentage of total shipments does each representative 

unit constitute within its design line? Should any other representative units be selected?

Design Option Combinations

For each representative unit, DOE is considering several design option combinations that 

characterize a range of efficiency levels for distribution transformers. This range spans from the 

efficiency level requirements set forth in DOE’s 2007 final rule to the maximum technologically 

available level. While many combinations of design options are possible to achieve these 

efficiency levels, DOE tried to select the most common designs in the industry.

A.5-2 Previously Unanalyzed Core Steel: DOE is examining a new core steel (M2) that was

not considered in the previous rulemaking. Does your company currently manufacture 

any medium-voltage dry-type transformers using M2 core steel? Are there any 
12A-15

manufacturing or engineering issues that DOE should be aware of when analyzing this 

core steel?

A.5-3 Amorphous Cores: DOE is examining amorphous cores as a design option for the 

medium-voltage dry-type design lines. Each of these amorphous designs utilizes a 

distributed gap wound core, which DOE assumes is purchased from an amorphous core 

manufacturer. Does your company currently manufacture medium-voltage dry-type 

transformers with an amorphous core? If so, for what kVA range are amorphous cores 

used? Does your company purchase amorphous ribbon or a finished amorphous core? If 

a finished amorphous core is purchased, who supplies the cores for your company? Are 

there any design issues associated with using an amorphous core in a medium-voltage 

dry-type transformer?

A.5-4 Core Type: DOE plans to examine designs for medium-voltage dry-type transformers 

using either a stacked butt-lap core or a stacked full-miter core. What core types does 

your company use in its medium-voltage dry-type transformer designs? Are there any 

manufacturing issues that DOE should be aware of when considering the different core 

types?

A.5-5 Medium-Voltage Dry-Type Design Option Combinations: In the tables below, please 

comment on the appropriateness of the design option combinations selected to 

characterize the range of possible efficiencies for each representative unit. Are these 

design option combinations similar to transformers that your company sells? Are there 

any additional designs that should be considered?
12A-16

Design Line 9: 300kVA, 150 ̊ C, three-phase, 60 Hz, 4160V Delta primary, 480Y/277V 

secondary, 45kV BIL

Core 

Material

Core 

Type

Conductor 

HV

Conductor 

LV

Design 

Type Comments

1 M6 Stacked 

Full Miter Cu Cu 3 – Legged

2 M5 Stacked 

Full Miter Al Al 3 – Legged

3 M4 Stacked 

Full Miter Al Al 3 – Legged

4 M3 Stacked 

Full Miter Cu Al 3 – Legged

5 M2 StackedButt-Lap Al Al 3 – Legged

6 H-0 DR Stacked 

Full Miter Cu Cu 3 – Legged

7

SA1 -

Amorphous DG Core Cu Cu 3 – Legged

Design Line 10: 1500kVA, 150 ̊ C, three-phase, 60 Hz, 4160V primary, 480Y/277V secondary, 

45kV BIL

Core 

Material Core Type Conductor HV

Conductor 

LV

Design 

Type Comments

1 M5 Stacked Cruc. 

Mitered Cu Al 3 – Legged

2 M4 Stacked Cruc. 

Mitered Cu Al 3 – Legged

3 M4 Stacked Cruc. 

Mitered Cu Cu 3 – Legged

4 M3 Stacked Cruc. 

Mitered Cu Cu 3 – Legged

5 H-0 DR Stacked Cruc. 

Mitered Cu Cu 3 – Legged
12A-17

Design Line 11: 300kVA, 150 ̊ C, three-phase, 60 Hz, 12470V primary, 480Y/277V secondary, 

95kV BIL

Core 

Material Core Type Conductor HV

Conductor 

LV

Design 

Type Comments

1 M6 Stacked Full 

Miter Cu Cu 3 – Legged

2 M5

Stacked Full 

Miter Al Al 3 – Legged

3 M4

Stacked Full 

Miter Cu Al 3 – Legged

4 M3

Stacked Full 

Miter Cu Cu 3 – Legged

5 H-0 DR Stacked Full 

Miter Cu Cu 3 – Legged

6

SA1 -

Amorphous DG Core Cu Cu 5 – Legged

Design Line 12: 1500kVa, 150 ̊ C, three-phase, 60 Hz, 12470V primary, 480Y/277V secondary, 

95kV BIL

Core 

Material Core Type Conductor HV

Conductor 

LV

Design 

Type Comments

1 M6 Stacked Cruc. 

Mitered Al Al 3 – Legged

2 M5 Stacked Cruc. 

Mitered Al Al 3 – Legged

3 M4 Stacked Cruc. 

Mitered Cu Al 3 – Legged

4 M4 Stacked Cruc. 

Mitered Cu Cu 3 – Legged

5 M3 Stacked Cruc. 

Mitered Cu Cu 3 – Legged

6 H-0 DR Stacked Cruc. 

Mitered Cu Cu 3 – Legged
12A-18

Design Line 13: 2000kVA, 150 ̊ C, three-phase, 60 Hz, 12470V primary, 480Y/277V 

secondary, 125kV BIL

Core 

Material Core Type Conductor HV

Conductor 

LV

Design 

Type Comments

1 M6 Stacked Cruc. 

Mitered Al Al 3 - Legged

2 M6 Stacked Cruc. 

Mitered Cu Cu 3 - Legged

3 M5 Stacked Cruc. 

Mitered Cu Al 3 - Legged

4 M4 Stacked Cruc. 

Mitered Cu Al 3 - Legged

5 M4 Stacked Cruc. 

Mitered Cu Cu 3 - Legged

6 M3 Stacked Cruc. 

Mitered Cu Cu 3 - Legged

7 H-0 DR Stacked Cruc. 

Mitered Cu Cu 3 - Legged
12A-19

A.6 Material Prices, Markups, and Labor Rates

Material Prices

DOE recognizes that material prices make up a significant portion of total cost for manufacturing 

distribution transformers. The following table contains DOE’s estimates for material prices for 

distribution transformers in each of the past five years. The prices listed do not include any 

markups for scrap, handling, factory overhead, non-production costs, or profit, but rather 

represent the price a manufacturer would pay for the material. All prices are listed in historic 

dollars (e.g., $2007 for year 2007, and $2009 for year 2009).

A.6-1 Material Prices: Please comment on the appropriateness of each material price. Does 

your company pay a similar price for these materials? If not, what price does your 

company pay? Would a five-year average of each material price be a fair 

characterization of its cost? If not, what time period should be used?
12A-20

Material Units 2010 2009 2008 2007 2006 Comments

M36 core steel (26 gauge) $/lb 0.69 0.69 0.69 0.84 0.60

M19 core steel (26 gauge) $/lb 0.95 0.85 0.98 0.95 0.73

M12 core steel $/lb 1.08 1.13 1.31 1.24 1.10

M6 core steel $/lb 1.52 1.95 1.87 1.78 1.50

M5 core steel $/lb 1.58 1.96 1.93 1.84 1.55

M4 core steel $/lb 1.74 2.02 1.98 1.89 1.59

M3 core steel $/lb 1.90 2.05 2.10 2.00 1.62

M3 core steel (Lite Carlite) $/lb 1.98

M2 core steel $/lb 2.02 2.10 2.22 2.12 1.66

M2 core steel (Lite Carlite) $/lb 2.13

H-O DR core steel (laser 

scribed) $/lb 2.06 2.10 2.28 2.14 1.76

ZDMH (mechanicallyscribed core steel) $/lb 2.05 2.09 2.27 2.16 1.75

SA1 (amorphous) finished 

core, volume production $/lb 2.38 2.27 2.86

Copper wire, formvar, 

round #10-20 $/lb 4.72 4.01 5.69 5.45 4.99

Copper wire, enameled, 

round #7-10 flattened $/lb 4.95 3.98 5.56 5.33 5.28

Copper wire, enameled, 

rectangular sizes $/lb 5.26 4.97 5.21 5.01 4.45

Copper wire, rectangular 

0.1 x 0.2, Nomex wrapped $/lb 4.87 4.10 5.83 5.68 5.20

Aluminum wire, formvar, 

round #9-17*

$/lb 5.94 4.17 4.47 4.05 1.68

Aluminum wire, formvar, 

round #7-10*

$/lb 4.39 4.19 4.50 4.12 1.71

Aluminum wire, 

rectangular 0.1 x 0.2, 

Nomex wrapped

$/lb 2.73 1.92 2.05 1.93 1.91

Copper strip, thickness 

range 0.02-0.045 $/lb 4.55 3.40 4.90 5.28 4.74

Copper strip, thickness 

range 0.030-0.060 $/lb 4.25 2.61 3.66 3.40 3.05

Aluminum strip, thickness 

range 0.02-0.045 $/lb 1.67 1.80 2.15 2.18 2.01

Aluminum strip, thickness 

range 0.045-0.080 $/lb 1.72 1.89 2.28 2.30 2.12

Kraft insulating paper with 

diamond adhesive $/lb 1.81 1.80 1.78 1.75 1.66

Nomex insulation $/lb 24.50 24.50 22.80 19.89 17.07

Cequin insulation $/lb 5.53 5.07 4.78 4.93 8.50

Mineral oil $/gal 3.78 3.20 3.50 2.30 1.82

Impregnation $/gal 22.55 22.50 21.45 21.35 21.35

Winding combs $/lb 12.34 12.58 12.10 11.52 7.56

Tank/Enclosure Steel $/lb 0.56 0.46 0.60 0.58 0.50

* DOE notes that the price quotations it received for aluminum wire, formvar, round #9-17 and #7-10 seem high 

relative to other materials and relative to the price in 2006. DOE asks for input on these material prices.
12A-21

Markups

DOE applies markups to all material prices to reflect a manufacturer’s internal markups. DOE’s 

analysis assumes that manufacturers will purchase a prefabricated amorphous core rather than 

purchasing raw material and constructing a core from it. For this reason, DOE applies different 

markups to the amorphous core price compared to the other raw material prices for scrap factor 

and factory overhead:

Scrap and handling factor: Applies to variable materials (e.g., core steel, windings, 

insulation, etc.). It accounts for the handling of material (loading into assembly or 

winding equipment) and the scrap material that cannot be used in the production of a 

finished transformer (e.g., lengths of wire too short to wind, trimmed core steel).

o Amorphous scrap factor: Accounts for breakage of prefabricated cores. Since 

amorphous cores are considered to be prefabricated, the regular scrap and 

handling factor does not apply, but a factor for breakage is considered.

o Mitered scrap factor: A higher scrap markup applies to steel used in full-mitered 

cores. This markup is higher than the regular scrap and handling factor to account 

for material cut from the notch in the yoke.

Factory overhead: Includes all the indirect costs associated with production, indirect 

materials and energy use (e.g., annealing furnace), taxes, and insurance. This markup is 

only applied to the direct material production costs.

Amorphous factory overhead: Reduces the factory overhead markup used for raw 

materials to adjust for a prefabricated core. Only accounts for portions of factory 

overhead that apply to a prefabricated core.

Non-production: Reflects costs including selling, general and administrative, R&D, 

interest payments, and profit factor. This markup is applied to the sum of direct material, 

direct labor, and factory overhead.

A.6-2 Markups: Please comment on the appropriateness of the following markups. Do they 

represent the markups your company uses? If not, what markups are used by your 

company? Would the amount of these markups differ greatly for any particular design 

type? Would your company reduce the markup allocation for prefabricated cores, such as 

was done for amorphous cores? 
12A-22

Type of Markup* Markup [%] Comments

Scrap and handling

 Regular scrap and 

 handling 2.5

 Amorphous scrap 1.5

 Mitered scrap 4.0

Factory overhead

 Regular Factory 

 Overhead 12.5

 Amorphous Factory

 Overhead 6.3

Non-production

 Regular non-

 production 25.0

* Only one markup from each type of markup (scrap and handling, factory overhead, and nonproduction) is used for a given material. For example, the amorphous markup would be 1.015 x 

1.063 x 1.25 = 1.348 (a 34.8 percent markup).

Labor Rate

DOE developed an estimate for the cost of labor by applying markups to a base hourly labor rate 

to obtain a fully-burdened labor rate. The base hourly labor rate was taken from Census data for 

NAICS code 3353111 “Power and distribution transformers, except parts” production workers 

hours and wages. DOE then applied the following markups to estimate the fully-burdened labor 

rate:

Indirect Production: Accounts for the cost of production managers, quality control, and 

other indirect costs associated with production.

Overhead: Includes commissions, dismissal pay, bonuses, vacation, sick leave, and 

social security contributions.

Fringe: Includes pension contributions, group insurance premiums, workers 

compensation, etc.

Assembly Labor Up-Time: Accounts for the time that workers are not assembling product 

and/or reworking unsatisfactory units.

Non-Production: Reflects costs including selling, general and administrative, R&D, 

interest payments, and profit factor. This markup is applied to the sum of direct material, 

direct labor, and factory overhead.
12A-23

A.6-3 Labor Rate: Please comment on the appropriateness of the following labor rate markups. 

Does the fully-burdened cost of labor represent your company’s fully-burdened labor rate 

for production? If not, what is your company’s fully-burdened labor rate, and which 

markups would you adjust?

Type of Markup Markup 

[%]

Rate per hour 

[$]

Comments

Labor cost per hour $ 16.80

Indirect Production 33 % $ 22.35

Overhead 30 % $ 29.05

Fringe 24 % $ 36.03

Assembly Labor Up-time 43 % $ 51.52

Non-Production 25 % $ 64.40

Fully-Burdened Cost of Labor $ 64.40
12A-24

B. MARKET QUESTIONNAIRE

B-1 Market Share: What is the estimated market share of your company in the U.S. 

distribution transformer industry? In the liquid-immersed, low-voltage dry-type, or 

medium-voltage dry-type market?

B-2 Domestic Manufacturing: What percent of distribution transformers sold in the U.S. are 

imported? What percent are manufactured domestically?

B-3 Delivery Channels: Who are the different intermediaries in the delivery channel between 

your company and the ultimate end users for liquid-immersed, low-voltage dry-type and 

medium-voltage dry-type transformers?

B-4 Transformer Purchasing Behavior: Has customer purchasing behavior changed in 

recent years, particularly in light of minimum efficiency standards? Do customers still 

purchase predominantly based on the lowest total owning cost for liquid-immersed 

transformers and based on lowest first cost for dry-type transformers? What is the 

estimated percentage of customers who provide no-load and load loss A and B values 

when purchasing a new distribution transformer? What, in $/W, are the average specified 

no-load and load loss values?

% that specify No-load loss (A)

$/Watt

Load loss (B)

$/Watt

Liquid-immersed

Low-voltage dry-type ( < 600V)

Medium-voltage dry-type ( > 600V)

B-5 Sales of Transformers by Efficiency: What is the range of efficiencies for distribution 

transformers that your company sells? What percent of transformers sold are at the 

minimum efficiency standard established by the previous DOE rulemaking? Does your 

company offer a premium efficiency distribution transformer, such as NEMA Premium 

rated transformers for low-voltage, dry-type? If so, what is its rated efficiency level at 

the kVA values used for DOE’s analysis?
12A-25

C. MANUFACTURER IMPACTS

During the Preliminary Analysis phase of the rulemaking, DOE attempts to characterize 

distribution transformer manufacturers on a high level. This includes any relevant issues they 

may face resulting from increased efficiency standards. During the next phase of the 

rulemaking, the Notice of Proposed Rulemaking (NOPR) phase, DOE will perform an in-depth 

analysis of the impacts on manufacturers.

C-1 Key Issues: What are the key issues for your company regarding any new energy 

conservation standards for distribution transformers?

C-2 Your Company’s Niches: What are your product lines, niches and relative strengths in 

the distribution transformers market?

C-3 Company Demographics: Where are your production facilities located, and what is the 

product mix manufactured at each location? Does the bulk of your company’s 

distribution transformer production occur domestically? What are your employment 

levels at these facilities? Are there any manufacturing or employment issues that DOE 

should be aware of in terms of producing more energy efficient transformers at your 

facility/facilities?

C-4 Materials and Material Prices: Are the materials necessary to build more energyefficient distribution transformers readily available? How would material price changes 

affect your company’s business?

C-5 Impacts: Generally how would new efficiency standards on distribution transformers

impact your customer mix, distribution channels and corresponding profit margins? 

Please explain.

C-6 Capital Investment: What level of capital expenditure and product conversion costs 

would you anticipate you may need to make at higher standard levels? Please describe 

these capital investments and provide your best estimate of their respective magnitudes.

C-7 Small Businesses: To what extent will new standards require small businesses to acquire 

new equipment or cause manufacturing process changes that could destabilize their 

business?

C-8 Facility Impacts: How would the imposition of new energy efficiency standards affect 

capacity utilization and manufacturing assets at your domestic production facilities? 
12A-26

Would a new standard result in stranded capital assets? Would any facilities be closed or 

downsized? Added or upgraded?

C-9 Depreciation: What are the depreciation periods for the three types of capital 

expenditures (building, equipment, and tooling)?

C-10 Compliance Costs: What specific annual compliance costs (after the effective date) do 

you anticipate incurring to comply with standards? Will they vary with standard level? 

Would these costs vary over time?

C-11 Exports and Competition: Would new standards change your projected export sales? 

Would new standards have an impact on the portion of the domestic market served by 

foreign competition?

C-12 Industry Consolidation: In the absence of new standards, do you expect any industry 

consolidation?

C-13 Competitive Positioning: How would new standards affect your ability to compete? 

Could new standards disproportionately advance or harm the competitive positions of 

some firms?

C-14 IP Issues: Are there concerns over intellectual property, patent licensing or other related 

issues?

C-15 Impacts on Consumers: Could new standards result in disproportionate economic or 

performance penalties for particular consumer/user subgroups? Beyond price and energy 

efficiency, could new standards result in products that will be more or less desirable to 

consumers due to changes in product functionality, utility or other features? 

C-16 Regulatory Burden: Are there recent or impending regulations on distribution 

transformers or related products that do or will impose a cumulative burden on the 

industry? What is the total expected impact of those other regulations?

C-17 Federal Tax Incentives: Are there any federal tax credits or other incentive programs to 

encourage you to produce energy efficient distribution transformers?