SPECIFICATIONS FOR THREE PHASE PAD-MOU NTE D

DISTRI BUTION TRANSFORMERS

SUBMITTALS

® Shop Drawings: Include transformer ratings, features, accessories,

compliance with the requirements specified herein, and conformance to

the referenced standards and proposed testing to be conducted at the

factory. Also include detailed and dimensioned plan, section and elevation

drawings showing all components and features, recommended torque

values for all electrical connections, complete wiring diagrams which

designate factory and field wiring (if applicable), and complete equipment

and material lists.

® Compliance Certification: Provide Manufacturers signed certification that

the equipment meets all of the requirements of these specifications and

the contract documents.

CERTIFIED FACTORY TESTING

All units shall be tested and certified for the following:

® No-load (Core) Losses at rated temperature (95°C).

® Full-load Winding Losses at rated temperature (95°C) and load.

® Percent Impedance Volts at rated temperature (95°C) and load.

® Excitation Current at 100% and 110% voltage.

® Winding Resistance measurement tests.

® Ratio tests for all tap settings.

® Polarity and Phase relation tests.

® Induced Potential tests.

® Full Wave and Reduced Wave Impulse tests.

® Applied Potential test.

® Insulation Power Factor test.

In addition , the manufacturer shall provide certification upon request for all

design and other tests listed in Table 17 of ANSI C57.12. 00 including verification

that the design has passed Short Circuit Criteria per ANSI C57. 12.00 and

C57.12.90.

REFERENCE STANDARDS

® All three phase pad-mounted distribution transformers shall be designed,

manufactured and tested in accordance with this specification and all

applicable ANSI and NEMA Standards, latest revision.

 EE-RM/STD-00-550 COMMENT 86

SPECIFICATIONS FOR THREE PHASE PAD-MOUNTED 

DISTRIBUTION TRANSFORMERS 

SUBMITTALS 

CD Shop Drawings: Include transformer ratings, features, accessories, 

compliance with the requirements specified herein, and conformance to 

the referenced standards and proposed testing to be conducted at the 

factory. Also include detailed and dimensioned plan, section and elevation 

drawings showing all components and features, recommended torque 

values for all electrical connections, complete wiring diagrams which 

designate factory and field wiring (if applicable), and complete equipment 

and material lists. 

CD Compliance Certification: Provide Manufacturers signed certification that 

the equipment meets all of the requirements of these specifications and 

the contract documents. 

CERTIFIED FACTORY TESTING 

All units shall be tested and certified for the following: 

CD No-load (Core) Losses at rated temperature (95°C). 

CD Full-load Winding Losses at rated temperature (95°C) and load. 

a Percent Impedance Volts at rated temperature (95°C) and load. 

a Excitation Current at 100% and 110% voltage. 

CD Winding Resistance measurement tests. 

a Ratio tests for all tap settings. 

CD Polarity and Phase relation tests. 

GIl Induced Potential tests. 

• Full Wave and Reduced Wave Impulse tests. 

CD Applied Potential test. 

a Insulation Power Factor test. 

In addition, the manufacturer shall provide certification upon request for all 

design and other tests listed in Table 17 of ANSI C57.12.00 including verification 

that the design has passed Short Circuit Criteria per ANSI C57.12.00 and 

C57.12.90. 

REFERENCE STANDARDS 

ED All three phase pad-mounted distribution transformers shall be designed, 

manufactured and tested in accordance with this specification and all 

applicable ANSI and NEMA Standards, latest revision. 
All characteristics, definitions, and terminology, except as specifically

covered in this specification, shall be in accordance with the latest revision

of the following ANSI and NEMA standards:

IEEE Standard C57.12.00 - General Requirements for Liquid-Immersed

Distribution, Power and Regulating Transformers.

IEEE Standard C57.12.26 - Pad-Mounted, Compartmental-Type, SelfCooled, Three-Phase Distribution Transformers For Use with Separable

Insulated High-Voltage Connectors, High Voltage, 34500GrdY/19920

Volts and Below; 2500 KVA and Smaller.

IEEE Standard C57.12. 28 - Pad-Mounted Equipment - Enclosure Integrity.

IEEE Standard C57.12.90 - IEEE Standard Test Code for LiquidImmersed Distribution, Power, and Regulating Transformers and IEEE

Guide for Short-Circuit Testing of Distribution and Power Transformers.

IEEE Standard C57.91 - Guide for Loading Mineral-Oil-Immersed

Overhead and Pad-Mounted Transformers Rated 500 KVA and Less with

65°C or 55°C Average Winding Rise.

IEEE Standard C57.92 - Guide for Loading Mineral-Oil-Immersed Power

Transformers Up to and including 100 MVA with 65°C or 55°C Average

Winding Rise.

® The primary and secondary voltages and associated lightning impulse

basic insulation levels (BIL) shall be in accordance with Table 1 below.

 EE-RM/STD-00-550 COMMENT 86

ED All characteristics, definitions, and terminology, except as specifically 

covered in this specification, shall be in accordance with the latest revision 

of the following ANSI and NEMA standards: 

IEEE Standard C57.12.00 - General Requirements for Liquid-Immersed 

Distribution, Power and Regulating Transformers. 

IEEE Standard C57.12.26 - Pad-Mounted, Compartmental-Type, SelfCooled, Three-Phase Distribution Transformers For Use with Separable 

Insulated High-Voltage Connectors, High Voltage, 34500GrdY/19920 

Volts and Below; 2500 KVA and Smaller. 

IEEE Standard C57.12.28 - Pad-Mounted Equipment - Enclosure Integrity. 

IEEE Standard C57.12.90 - IEEE Standard Test Code for LiquidImmersed Distribution, Power, and Regulating Transformers and IEEE 

Guide for Short-Circuit Testing of Distribution and Power Transformers. 

IEEE Standard C57.91 - Guide for Loading Mineral-Oil-Immersed 

Overhead and Pad-Mounted Transformers Rated 500 KVA and Less with 

65°C or 55°C Average Winding Rise. 

IEEE Standard C57.92 - Guide for Loading Mineral-Oil-Immersed Power 

Transformers Up to and including 100 MVA with 65°C or 55°C Average 

Winding Rise. 

• The primary and secondary voltages and associated lightning impulse 

basic insulation levels (BIL) shall be in accordance with Table 1 below. 
Table I

Transformer and Connector High-Voltage Ratings and Electrical

Characteristics

Electrical Characteristics of the Completely Assembled

Transformer High-Voltage Connectors

60-Hz dry

High-Voltage Rating Z. BIL one minute

High-Voltage Ratings (volts) Minimum Phase-to-Ground' (kV) withstand

BIL 3. (kV) /Phase-to-Phase (kV) (kV)

Single High-Voltage

2400 60 8.3/14.4 95 34

4160 60 8.3/14.4 95 34

4800 60 8.3/14.4 95 34

7200 75 8.3/14.4 95 34

12000 95 8.3/14.4 95 34

12470 95 8.3/14.4 95 34

13200 95 8.3/14.4 95 34

13800 95 8.3/14.4 95 34

14400 95 8.3/14.4 95 34

16430 95 8.3/14.4 95 34

4160GrdY/2400 60 8.3/14.4 95 344

8320GrdY/4800 75 8.3/14.4 95 344

12470GrdY/7200 95 8.3/14.4 95 344

13200GrdY/7620 95 8.3/14.4 95 344

13800GrdY/7970 95 8.3/14.4 95 344.

22860GrdY/13200 125 15.2/26.3 125 404.

23900OrdY/13800 125 15.2/26.3 125 404.

24940GrdY/14400 125 15.2/26.3 125 404.

34500GrdY/19920 150 21.1/36.6 150 50

Series-Multiple High-Voltage

4160GrdY/2400 x 12470GrdY/7200 60 x 95 8.3/14.4 95 34

4160GrdY/2400 x 13200GrdY/7600 60 x 95 8.3/14.4 95 34

4800 x 13200OrdY/7620 60 x 95 8.3/14.4 95 34

8320GrdY/4800 x 24940GrdY/14400 75 x 125 15.2/26.3 125 40

12470GrdY/7200 x 24940GrdY/14400 95 x 125 15.2/26.3 125 40

13200GrdY/7620 x 24940GrdY/14400 95 x 125 15.2/26.3 125 40

23900GrdY/13800 x 34500GrdY/19920 125 x 150 21.1/36.6 150 50

1. For complete connector rating, see ANSI/IEEE 386.

2. Transformers shall be suitable for connectors with phase-to-ground or phase-toground/phase-to-phase high-voltage ratings as listed.

3. Surge Arrester insulation coordination may require higher BIL on multiple connection

windings than indicated to achieve a minimum protective level margin of 20%.

4. Grounded-Wye connected transformers (non series-multiple ) 1000kVA and below may

be designed with reduced insulation at the neutral and tested in accordance with

C57.12.26 paragraph 6.2 for deadfront units.

 EE-RM/STD-00-550 COMMENT 86

Table 1 

Transformer and Connector High-Voltage Ratings and Electrical 

Characteristics 

Electrical Characteristics of the Completely Assembled 

Transformer High-Voltage Connectors 1. 

High-Voltage Rating 2. BIL 

High-Voltage Ratings (volts) Minimum Phase-to-Ground . (kV) 

BIL 3. (kV) /Phase-to-Phase (kV) 

Single High-Voltage 

2400 60 8.3/14.4 95 

4160 60 8.3/14.4 95 

4800 60 8.3/14.4 95 

7200 75 8.3/14.4 95 

12000 95 8.3/14.4 95 

12470 95 8.3/14.4 95 

13200 95 8.3/14.4 95 

13800 95 8.3/14.4 95 

14400 95 8.3/14.4 95 

16430 95 8.3/14.4 95 

4160GrdY/2400 60 8.3/14.4 95 

8320GrdY /4800 75 8.3/14.4 95 

12470GrdY/7200 95 8.3/14.4 95 

13200GrdY/7620 95 8.3/14.4 95 

13800GrdY/7970 95 8.3/14.4 95 

22860GrdY/13200 125 15.2/26.3 125 

23900GrdY/13800 125 15.2/26.3 125 

24940GrdY/14400 125 15.2/26.3 125 

34500GrdY/19920 150 21.1/36.6 150 

Series-Multiple High-Voltage 

4160GrdY/2400 x 12470GrdY/7200 60 x 95 8.3/14.4 95 

4160GrdY/2400 x 13200GrdY/7600 60 x 95 8.3/14.4 95 

4800 x 13200GrdY/7620 60 x 95 8.3/14.4 95 

8320GrdY/4800 x 24940GrdY/14400 75 x 125 15.2/26.3 125 

12470GrdY/7200 x 24940GrdY/14400 95 x 125 15.2/26.3 125 

13200GrdY/7620 x 24940GrdY/14400 95 x 125 15.2/26.3 125 

23900GrdY/13800 x 34500GrdY/19920 125 x 150 21.1/36.6 150 

1. For complete connector rating, see ANSIJlEEE 386. 

2. Transformers shall be suitable for connectors with phase-to-ground or phase-toground/phase-to-phase high-voltage ratings as listed. 

3. Surge Arrester insulation coordination may require higher BIL on multiple connection 

windings than indicated to achieve a minimum protective level margin of 20%. 

4. Grounded-Wye connected transformers (non series-multiple) 1000kVA and below may 

be designed with reduced insulation at the neutral and tested in accordance with 

C57.12.26 paragraph 6.2 for deadfront units. 

60-Hz dry 

one minute 

withstand 

(kV) 

34 

34 

34 

34 

34 

34 

34 

34 

34 

34 

344 . 

344 

344 

344. 

344. 

404. 

404. 

404. 

50 

34 

34 

34 

40 

40 

40 

50 
PRODUCTS

This Bid Request is for the following three phase pad-mounted distribution

transformer equipment:

® Bid Item #1 : Two (2) 2000kVA @ 65 °C temperature rise, three phase

pad-mounted transformer with a nominal primary voltage of

12,470GrdY/7,200V, and a nominal secondary voltage of

4,160GrdY/2,400V (Playtex Products and spare).

® Bid Item #2: One (1) 1000kVA @ 65°C temperature rise, three phase

pad-mounted transformer with a nominal primary voltage of

12,47OGrdY/7,200V and a nominal secondary voltage of

4,160GrdY/2,400V (Playtex Apparel 3A & 3B).

® Bid Item #3: One (1) 300kVA @ 65°C temperature rise, three phase

pad-mounted transformer with a nominal primary voltage of

12,47OGrdY/7,200V and a nominal secondary voltage of

4,160GrdY/2,400V (Court House).

® Bid Item #4: One (1) 150kVA @ 65°C temperature rise, three phase

pad-mounted transformer with a nominal primary voltage of

12,47OGrdY/7,200V and a nominal secondary voltage of

4,160GrdY/2,400V (PNC Bank).

GENERAL

All three phase pad-mounted distribution transformers shall be the

completely factory fabricated compartmental type, mineral oil-immersed,

self-cooled, with loop-feed dead-front primary winding connections and

radial-feed dead-front secondary winding connections (for transformers with

ratings less than or equal to 1000kVA), two (2) each 2 1/2% primary

winding taps above and below nominal voltage rating with an external tap

switch for de-energized operation, and provided with integral primary

voltage protection in the form of appropriately sized load break bayonet type

expulsion fuses in series with backup current limiting fuses under oil.

 EE-RM/STD-00-550 COMMENT 86

PRODUCTS 

This Bid Request is for the following three phase pad-mounted distribution 

transformer equipment: 

• Bid Item #1: Two (2) 2000kVA @ 65°C temperature rise, three phase 

pad-mounted transformer with a nominal primary voltage of 

12,470GrdY17,200V, and a nominal secondary voltage of 

4, 160GrdY 12,400V (Playtex Products and spare). 

• Bid Item #2: One (1) 1000kVA @ 65°C temperature rise, three phase 

pad-mounted transformer with a nominal primary voltage of 

12,470GrdY17,200V and a nominal secondary voltage of 

4, 160GrdYI2,400V (Playtex Apparel3A & 3B). 

• Bid Item #3: One (1) 300kVA @ 65°C temperature rise, three phase 

pad-mounted transformer with a nominal primary voltage of 

12,470GrdY17,200V and a nominal secondary voltage of 

4,160GrdY/2,400V (Court House). 

• Bid Item #4: One (1) 150kVA @ 65°C temperature rise, three phase 

pad-mounted transformer with a nominal primary voltage of 

12,470GrdY17,200V and a nominal secondary voltage of 

4, 160GrdY/2,400V (PNC Bank). 

GENERAL 

All three phase pad-mounted distribution transformers shall be the 

completely factory fabricated compartmental type, mineral oil-immersed, 

self-cooled, with loop-feed dead-front primary winding connections and 

radial-feed dead-front secondary winding connections (for transformers with 

ratings less than or equal to I OOOkV A), two (2) each 2 112% primary 

winding taps above and below nominal voltage rating with an external tap 

switch for de-energized operation, and provided with integral primary 

voltage protection in the form of appropriately sized load break bayonet type 

expulsion fuses in series with backup current limiting fuses under oil. 
MANUFACTURES QUALIFICATIONS

Only Firms experienced in manufacturing equipment of the types and

capacities indicated that are able to show evidence of continuous

engagement in the manufacture of pad-mounted transformers for the last five

(5) years will be considered.

WARRANTY

All three phase pad-mounted transformers shall be warranted to be free from

defects in material and workmanship for a period of twelve (12) months

from the date of installation or eighteen (18) months from the date of

delivery whichever is longer.

AWARD OF BID

The City of Dover reserves the right not to award the Contract to the lowest

bidder, based upon delivery schedule, loss evaluation, qualifications of the

bidder/manufacturer, technical issues encountered during bid evaluation,

compliance with the City's Specifications and Contract Documents, and the

Terms and Conditions of Sale.

RATINGS

® The average winding temperature rise above a 30°C 24 hour average with

a 40°C peak ambient temperature, when tested at the transformer rating,

shall not exceed 65°C.

® The percent impedance voltage, as measured on the rated nominal

voltage connection, shall be per IEEE C57.12.26, paragraph 5.1.

Manufacturing tolerance for impedance values shall be per ANSI

C57.12.00, Table 19.

KVA

Rating

Low-Voltage Rating < 4, 160 GrdY/2400V

With High Voltage Rating shown below

< 150 kV BIL 200 kV BIL 250 kV BIL

45-75 1.00-5.00 7.25 7.75

112.5 - 300 1.20-6.0 7.25 7.75

500 1.50-7.00 7.25 7.75

750 - 2500 5.75 7.25 7.75

Table 2

Percent Im pedance Volta ge

 EE-RM/STD-00-550 COMMENT 86

MANUFACTURES QUALIFICATIONS 

Only Firms experienced in manufacturing equipment of the types and 

capacities indicated that are able to show evidence of continuous 

engagement in the manufacture of pad-mounted transformers for the last five 

(5) years will be considered. 

WARRANTY 

All three phase pad-mounted transformers shall be warranted to be free from 

defects in material and workmanship for a period of twelve (12) months 

from the date of installation or eighteen (18) months from the date of 

delivery whichever is longer. 

AWARD OF BID 

The City of Dover reserves the right not to award the Contract to the lowest 

bidder, based upon delivery schedule, loss evaluation, qualifications of the 

bidder/manufacturer, technical issues encountered during bid evaluation, 

compliance with the City's Specifications and Contract Documents, and the 

Terms and Conditions of Sale. 

RATINGS 

€I The average winding temperature rise above a 30°C 24 hour average with 

a 40°C peak ambient temperature, when tested at the transformer rating, 

shall not exceed 65°C. 

€I The percent impedance voltage, as measured on the rated nominal 

voltage connection, shall be per IEEE C57.12.26, paragraph 5.1. 

Manufacturing tolerance for impedance values shall be per ANSI 

C57.12.00, Table 19. 

Table 2 

P ercen tid mpe ance V o It age 

KVA low-Voltage Rating ~ 4,160 GrdY/2400V 

Rating With High Voltage Rating shown below 

< 150 kV Bll 200 kV Bll ?"n I," Dl1 

45-75 1.00 - 5.00 7.25 7.75 

112.5 - 300 1.20 - 6.0 7.25 7.75 

500 1.50 - 7.00 7.25 7.75 

750 - 2500 5.75 7.25 7.75 
CORE AND COIL ASSEMBLY

® The core and coils shall be vacuum processed to ensure maximum

penetration of insulating fluid into the coil insulation system. The

transformer shall be filled with preheated, filtered and degassed insulating

fluid. The core shall be manufactured from burr-free, grain-oriented or

amorphous silicon steel and shall be precisely stacked to eliminate gaps in

the corner joints. The winding coils shall be insulated with diamond

pattern, epoxy-coated insulating paper, which shall be thermally cured

under pressure to ensure proper bonding of the winding conductor and

paper insulation.

® Copper primary and secondary windings are preferred. Substitution of

aluminum windings may be considered if they provide a substantial cost

savings when transformer first cost and loss-evaluated cost are

considered.

® The transformer low voltage windings shall have a three phase, 60 Hz

rating equivalent to the transformer primary windings.

GENERAL

Sealed pad-mounted transformer tanks shall be provided with the necessary

cooling radiators and individual high voltage and low voltage cable compartments

separated by a steel barrier. The enclosure shall have no exposed removable

parts, no exposed openings, be tamper proof, weather proof, and suitable for pad

mounting. Cable compartment doors, door-sills and hoods shall be removable.

TANK AND TERMINAL COMPARTMENT

® The terminal compartment depth shall be in accordance with Figure 7 of

ANSI C57.12.26.

® Doors: Separate doors shall be provided for high and low voltage cable

terminal compartments with mechanical interlocks so that access to the

high voltage compartment is prevented unless the low voltage

compartment is open . Doors to include open position door-stops and

stainless steel hinges and pins. The low voltage compartment door shall

incorporate a three-point locking mechanism to assure a tight and secure

door closing, and latching handle with provisions for a single padlock to

secure both compartments. In addition to the regular locking provision, all

access doors and hoods shall be secured by a recessed, captive pentahead bolt that meets the dimensions set forth in ANSI C57. 12.28.

 EE-RM/STD-00-550 COMMENT 86

CORE AND COIL ASSEMBLY 

• The core and coils shall be vacuum processed to ensure maximum 

penetration of insulating fluid into the coil insulation system. The 

transformer shall be filled with preheated, filtered and degassed insulating 

fluid. The core shall be manufactured from burr-free, grain-oriented or 

amorphous silicon steel and shall be precisely stacked to eliminate gaps in 

the corner joints. The winding coils shall be insulated with diamond 

pattern, epoxy-coated insulating paper, which shall be thermally cured 

under pressure to ensure proper bonding of the winding conductor and 

paper insulation. 

• Copper primary and secondary windings are preferred. Substitution of 

aluminum windings may be considered if they provide a substantial cost 

savings when transformer first cost and loss-evaluated cost are 

considered. 

• The transformer low voltage windings shall have a three phase, 60 Hz 

rating equivalent to the transformer primary windings. 

GENERAL 

Sealed pad-mounted transformer tanks shall be provided with the necessary 

cooling radiators and individual high voltage and low voltage cable compartments 

separated by a steel barrier. The enclosure shall have no exposed removable 

parts, no exposed openings, be tamper proof, weather proof, and suitable for pad 

mounting. Cable compartment doors, door-sills and hoods shall be removable. 

TANK AND TERMINAL COMPARTMENT 

• The terminal compartment depth shall be in accordance with Figure 7 of 

ANSI C57.12.26. 

• Doors: Separate doors shall be provided for high and low voltage cable 

terminal compartments with mechanical interlocks so that access to the 

high voltage compartment is prevented unless the low voltage 

compartment is open. Doors to include open position door-stops and 

stainless steel hinges and pins. The low voltage compartment door shall 

incorporate a three-point locking mechanism to assure a tight and secure 

door closing, and latching handle with provisions for a single padlock to 

secure both compartments. In addition to the regular locking provision, all 

access doors and hoods shall be secured by a recessed, captive pentahead bolt that meets the dimensions set forth in ANSI C57.12.28. 
® The tank must be welded using precision cut, cold-rolled steel and

equipped with extra-heavy duty, welded-in-place lifting lugs and jacking

pads. The tank base must be designed to allow skidding or rolling in any

direction.

® The transformer shall be of sealed tank construction with sufficient

strength to withstand a pressure of 7 psig without permanent distortion,

and 15 psig without rupturing or affecting cabinet security per ANSI

C57.12.26 paragraph 7.5.2. The tank shall include a pressure relief valve

with a flow at 15 psig of 35 SCFM minimum, or as required to meet the

listing of the insulating fluid. The venting and sealing characteristics shall

be as follows:

3 Cracking Pressure: 10 psig ± 2 psig

3 Resealing Pressure: 6 psig minimum

3 Zero leakage from resealing pressure to -8 psig

® The tank shall be cleaned with an alkaline cleaning agent to remove

grease and oil. An iron phosphate coating shall then be chemically

bonded to the metal to assure coating adhesion and to retard corrosion.

The tank shall be primed with an electrodeposited powder epoxy to

provide a barrier against moisture , salt, and corrosives . The tank shall

then be coated with two coats of Standard Munsell No . 7GY3 .29/1.5

Green . The tank coating shall meet all requirements in ANSI C57.12.28

including:

3 Salt Spray Test

3 Crosshatch Adhesion Test

3 Humidity Test

3 Impact Test

3 Oil Resistance Test

3 Ultraviolet Accelerated Weathering Test

3 Abrasion Resistance - Taber Abraser

® The transformers tanks shall have a catalytic epoxy coal tar composition

applied to the bottom for extra protection against corrosion.

® The pad-mounted equipment shall meet the requirements for tamper

resistance set forth in ANSI C57.12.28 including but not limited to the pry

test, pull test, and wire probe test.

® The tank shall be complete with an anodized aluminum or stainless steel

laser engraved or stamped nameplate. This nameplate shall meet ANSI

C57.12.00 for Nameplate B.

 EE-RM/STD-00-550 COMMENT 86

e The tank must be welded using precision cut, cold-rolled steel and 

equipped with extra-heavy duty, welded-in-place lifting lugs and jacking 

pads. The tank base must be designed to allow skidding or rolling in any 

direction. 

e The transformer shall be of sealed tank construction with sufficient 

strength to withstand a pressure of 7 psig without permanent distortion, 

and 15 psig without rupturing or affecting cabinet security per ANSI 

C57.12.26 paragraph 7.5.2. The tank shall include a pressure relief valve 

with a flow at 15 psig of 35 SCFM minimum, or as required to meet the 

listing of the insulating fluid. The venting and sealing characteristics shall 

be as follows: 

./ Cracking Pressure: 10 psig ± 2 psig 

./ Resealing Pressure: 6 psig minimum 

./ Zero leakage from resealing pressure to -8 psig 

e The tank shall be cleaned with an alkaline cleaning agent to remove 

grease and oil. An iron phosphate coating shall then be chemically 

bonded to the metal to assure coating adhesion and to retard corrosion. 

The tank shall be primed with an electrodeposited powder epoxy to 

provide a barrier against moisture, salt, and corrosives. The tank shall 

then be coated with two coats of Standard Munsell No. 7GY3.29/1.5 

Green. The tank coating shall meet all requirements in ANSI C57.12.28 

including: 

./ Salt Spray Test 

./ Crosshatch Adhesion Test 

./ Humidity Test 

./ Impact Test 

./ Oil Resistance Test 

./ Ultraviolet Accelerated Weathering Test 

./ Abrasion Resistance - Taber Abraser 

e The transformers tanks shall have a catalytic epoxy coal tar composition 

applied to the bottom for extra protection against corrosion. 

e The pad-mounted equipment shall meet the requirements for tamper 

resistance set forth in ANSI C57.12.28 including but not limited to the pry 

test, pull test, and wire probe test. 

o The tank shall be complete with an anodized aluminum or stainless steel 

laser engraved or stamped nameplate. This nameplate shall meet ANSI 

C57.12.00 for Nameplate B. 
INSULATING FLUID

® The dielectric coolant in the transformer must be new, highly refined and

inhibited 10 C mineral oil and meet the minimum requirements as

specified in Table 1, "Functional Property Requirements", of ASTM D3487

and ANSI C57.106.

® All transformer oil must be bulk tested for polychlorinated biphenyls

(PCBs) per ASTM D4059 and certified as having no detectable level of

PCBs. The pad- mounted transformers shall be certified and labeled nonPCB, and provided with a certified test report to ASTM standards for

documenting insulating oil, color, acidity, dielectric strength, interfacial

tension, visual appearance, and water content.

HIGH VOLTAGE COMPARTMENT

® The voltage provided and the basic insulation level (BIL) shall be in

accordance with Table 1.

® The pad mounted transformers shall have primary winding connections

constructed for dead front loop feed operation and supplied with six (6)

universal deep well bushing assemblies and six (6) universal 200A loadbreak bushing inserts capable of accepting ESNA standard, 15kV class,

200A load break elbows conforming to ANSI/IEEE 386. The bushing well

assemblies shall be externally removable and clamped and have an

integral molded semi-conductive shield. These assemblies, with the

appropriate 200A load-break bushing inserts shall allow for the use of

bushing position elbow-type surge arrestors.

® The pad-mounted transformers shall have separate HV and LV winding

external fully insulated neutral bushings provided with removable

grounding connections between the HV and LV neutral bushings and the

NEMA standard transformer ground pad to facilitate transformer testing.

® The bushing heights shall be in accordance with Figure 7 of ANSI

C57.12.26.

® Cable accessory parking stands shall be provided and shall be located

such that the separable insulated load break connectors that are designed

for energized operation with the transformer in its permanent location can

be operated by hot-line tools.

 EE-RM/STD-00-550 COMMENT 86

INSULATING FLUID 

• The dielectric coolant in the transformer must be new, highly refined and 

inhibited 10 C mineral oil and meet the minimum requirements as 

specified in Table 1, "Functional Property Requirements", of ASTM D3487 

and ANSI C57.106. 

• All transformer oil must be bulk tested for polychlorinated biphenyls 

(PCBs) per ASTM D4059 and certified as having no detectable level of 

PCBs. The pad- mounted transformers shall be certified and labeled nonPCB, and provided with a certified test report to ASTM standards for 

documenting insulating oil, color, acidity, dielectric strength, interfacial 

tension, visual appearance, and water content. 

HIGH VOLTAGE COMPARTMENT 

• The voltage provided and the basic insulation level (BIL) shall be in 

accordance with Table 1. 

• The pad mounted transformers shall have primary winding connections 

constructed for dead front loop feed operation and supplied with six (6) 

universal deep well bushing assemblies and six (6) universal 200A loadbreak bushing inserts capable of accepting ESNA standard, 15kV class, 

200A load break elbows conforming to ANSIIIEEE 386. The bushing well 

assemblies shall be externally removable and clamped and have an 

integral molded semi-conductive shield. These assemblies, with the 

appropriate 200A load-break bushing inserts shall allow for the use of 

bushing position elbow-type surge arrestors. 

o The pad-mounted transformers shall have separate HV and LV winding 

external fully insulated neutral bushings provided with removable 

grounding connections between the HV and LV neutral bushings and the 

NEMA standard transformer ground pad to facilitate transformer testing. 

o The bushing heights shall be in accordance with Figure 7 of ANSI 

C57.12.26. 

e Cable accessory parking stands shall be provided and shall be located 

such that the separable insulated load break connectors that are designed 

for energized operation with the transformer in its permanent location can 

be operated by hot-line tools. 
LOW VOLTAGE COMPARTMENT

® The voltage provided and the basic insulation level (BIL) shall be in

accordance with Table 1.

® The pad mounted transformers with ratings less than or equal to 1000kVA

shall have secondary winding connections constructed for radial-feed

dead-front operation and supplied with three (3) universal deep well

bushing assemblies and three (3) universal 200A load-break bushing

inserts capable of accepting ESNA standard , 15kV class, 200A load break

elbows conforming to ANSI/IEEE 386 . The bushing well assemblies shall

be externally removable and clamped and have an integral molded semiconductive shield.

® Cable accessory parking stands shall be provided and shall be located

such that the separable insulated load break connectors that are designed

for energized operation with the transformer in its permanent location can

be operated by hot-line tools.

® The transformer low voltage phase and neutral bushings for the units

rated 2000kVA shall be one-piece epoxy, porcelain, or fiberglass polyester

material with silver-plated copper flat pad terminal spades and NEMA

standard 4-hole drilling. The low-voltage bushings shall be the bolted type

with external clamping. The low-voltage bushing terminals shall be in

accordance with Figure 9 of ANSI C57.12.26.

® If the transformer is equipped with threaded stud-type phase and neutral

terminals, these terminals shall be provided with silver-plated copper flat

pad stud connectors with NEMA standard 4-hole drilling installed for the

phase and neutral terminals.

® The configuration of the transformer low voltage bushings shall be in

accordance with ANSI C57.12.26, Figure 8. The secondary bushings shall

be replaceable utilizing the access provided or through the removal of the

sealed tank access cover.

® The bushing heights shall be in accordance with Figure 7 of ANSI

C57.12.26.

PROTECTION

® The over-current protection scheme provided with the transformer shall

consist of the following attributes. If for any reason a protection scheme

other than the following is required it shall be clearly stated as an

exception on the bid.

 EE-RM/STD-00-550 COMMENT 86

LOW VOLTAGE COMPARTMENT 

EI The voltage provided and the basic insulation level (BIL) shall be in 

accordance with Table 1. 

EI The pad mounted transformers with ratings less than or equal to 1000kVA 

shall have secondary winding connections constructed for radial-feed 

dead-front operation and supplied with three (3) universal deep well 

bushing assemblies and three (3) universal 200A load-break bushing 

inserts capable of accepting ESNA standard, 15kV class, 200A load break 

elbows conforming to ANSIIIEEE 386. The bushing well assemblies shall 

be externally removable and clamped and have an integral molded semiconductive shield. 

EI Cable accessory parking stands shall be provided and shall be located 

such that the separable insulated load break connectors that are designed 

for energized operation with the transformer in its permanent location can 

be operated by hot-line tools. 

• The transformer low voltage phase and neutral bushings for the units 

rated 2000kVA shall be one-piece epoxy, porcelain, or fiberglass polyester 

material with silver-plated copper flat pad terminal spades and NEMA 

standard 4-hole drilling. The low-voltage bushings shall be the bolted type 

with external clamping. The low-voltage bushing terminals shall be in 

accordance with Figure 9 of ANSI C57.12.26. 

• If the transformer is equipped with threaded stud-type phase and neutral 

terminals, these terminals shall be provided with silver-plated copper flat 

pad stud connectors with NEMA standard 4-hole drilling installed for the 

phase and neutral terminals. 

• The configuration of the transformer low voltage bushings shall be in 

accordance with ANSI C57.12.26, Figure 8. The secondary bushings shall 

be replaceable utilizing the access provided or through the removal of the 

sealed tank access cover. 

• The bushing heights shall be in accordance with Figure 7 of ANSI 

C57.12.26. 

PROTECTION 

• The over-current protection scheme provided with the transformer shall 

consist of the following attributes. If for any reason a protection scheme 

other than the following is required it shall be clearly stated as an 

exception on the bid. 
® The transformer primary shall include load break Bay-O-Net fuse

assemblies with flapper valves and drip shields to minimize oil spillage.

Over-current protection shall be provided by Bay-O-Net expulsion fuses

mounted in series with partial range under-oil ELSP (or equivalent)

current-limiting fuses with an interrupting rating of 50,000 A. This fusing

scheme is intended to provide full range protection for system reliability

and safety of operating personnel where distribution primary single phase

to ground fault currents may exceed 3500A.

ACCESSORIES

The following standard accessories shall be provided:

® Four (4) each lifting lugs and jacking plates.

® Penta-head bolted doors and hoods w/ bolt guard

® 1.0" upper fill plug

® 1.0" drain/sampling valve in the low voltage compartment

® Automatic pressure relief device

® 20" deep HV and LV terminal compartments

® Stainless steel NEMA Standard two hole ground pads

The following optional accessories shall be provided:

• Liquid level gauge

® Pressure/vacuum gauge

® Dial type thermometer

® High voltage (and low voltage where applicable) 200A universal

bushing well inserts

® Ground connectors

® Touch-up paint

LOSS EVALUATION

The following penalties will be assigned to transformer losses during the bid

evaluation process:

® $4,000/kW for No-load (Core) losses

* $1 000/kW for full load (OA) winding losses.

HAZARD ALERTING SIGNS

 EE-RM/STD-00-550 COMMENT 86

• The transformer primary shall include load break Bay-a-Net fuse 

assemblies with flapper valves and drip shields to minimize oil spillage. 

Over-current protection shall be provided by Bay-O-Net expulsion fuses 

mounted in series with partial range under-oil ELSP (or equivalent) 

current-limiting fuses with an interrupting rating of 50,000 A. This fusing 

scheme is intended to provide full range protection for system reliability 

and safety of operating personnel where distribution primary single phase 

to ground fault currents may exceed 3500A. 

ACCESSORIES 

The following standard accessories shall be provided: 

• Four (4) each lifting lugs and jacking plates. 

• Penta-head bolted doors and hoods w/ bolt guard 

• 1.0" upper fill plug 

• 1.0" drain/sampling valve in the low voltage compartment 

• Automatic pressure relief device 

• 20" deep HV and LV terminal compartments 

• Stainless steel NEMA Standard two hole ground pads 

The following optional accessories shall be provided: 

• Liquid level gauge 

• Pressure/vacuum gauge 

• Dial type thermometer 

• High voltage (and low voltage where applicable) 200A universal 

bushing well inserts 

III Ground connectors 

• Touch-up paint 

LOSS EVALUATION 

The following penalties will be assigned to transformer losses during the bid 

evaluation process: 

III $4,000/kW for No-load (Core) losses 

• $1 OOO/kW for full load (OA) winding losses. 

HAZARD ALERTING SIGNS 
® The exterior of the pad-mounted enclosure shall be provided with

"WARNING-KEEP OUT-HAZARDOUS VOLTAGE INSIDE- CAN

SHOCK, BURN OR CAUSE DEATH" signs.

® The interior of the pad-mounted enclosure shall be provided with a

"DANGER-HAZARDOUS VOLTAGE-FAILURE TO FOLLOW THESE

INSTRUCTIONS WILL LIKELY CAUSE SHOCK, BURNS OR DEATH"

sign. The text will further indicate that operating personnel must know and

obey the employer's work rules, know the hazards involved, and use

proper protective tools to work on this equipment.

MISCELLANEOUS

Operation and Maintenance Manual: provide 8-1/2" x 11" bound manual including

all shop drawing information, spare parts list with model numbers, local service

facilities, and recommended maintenance and testing procedures.

DELIVERY

Each individual pad-mounted transformer unit shall be bonded or bolted to a

wooden pallet made with "4 by 4 lumber" minimum. To facilitate the City's

unloading from the delivery truck and handling by fork-lift or aerial lifts/derrick and

slings, the pad-mounted transformers must be shipped on an open type truck.

Each unit shall be protected from paint damage while in transit.

Transformers Sh ipped such that they cannot be lifted in

th is manner will not be accepted.

 EE-RM/STD-00-550 COMMENT 86

• The exterior of the pad-mounted enclosure shall be provided with 

"WARNING·KEEP OUT·HAZARDOUS VOLTAGE INSIDE· CAN 

SHOCK, BURN OR CAUSE DEATH" signs. 

• The interior of the pad-mounted enclosure shall be provided with a 

"DANGER-HAZARDOUS VOLTAGE-FAILURE TO FOLLOW THESE 

INSTRUCTIONS WILL UKEL Y CAUSE SHOCK, BURNS OR DEATH" 

sign. The text will further indicate that operating personnel must know and 

obey the employer's work rules, know the hazards involved, and use 

proper protective tools to work on this equipment. 

MISCELLANEOUS 

Operation and Maintenance Manual: provide 8-1/2" x 11" bound manual including 

all shop drawing information, spare parts list with model numbers, local service 

facilities, and recommended maintenance and testing procedures. 

DELIVERY 

Each individual pad-mounted transformer unit shall be bonded or bolted to a 

wooden pallet made with "4 by 4 lumber" minimum. To facilitate the City's 

unloading from the delivery truck and handling by fork-lift or aerialliftslderrick and 

slings, the pad-mounted transformers must be shipped on an open type truck. 

Each unit shall be protected from paint damage while in transit. 

Transformers shipped such that they cannot be lifted in 

this manner will not be accepted.