Single Phase Pad Mounted Transformer

  • Primary Voltage Ratings: 34.5kV/19.92kV, 24.94kV/14.4kV, 13.8kV/7.957kV, 13.2kV/7.62kV, 12.47kV/7.2kV or others
  • Secondary Voltage Ratings: 120/240V, 240/480V, 347V, 600V or others
  • H.V. TAP RANGE: ±2×2.5% or others
  • TYPE: Loop feed/Radial feed
  • BIL: 30-150
  • Standards: ANSI, IEEE, DOE, CSA, NEMA, UL
  • Application: Residential Areas, Hotels, Single Family Houses, Parks, Underground Distribution Systems
  • Power Rating: 15-250 kVA

The single-phase pad-mounted transformer rated capacity is 15-250 kVA. Single-phase Pad-mounted Transformer is generally used in places where single-phase power is required for civil use, such as household appliances, etc., and its capacity is relatively smaller than a three-phase pad-mounted transformer.

Quote Now


CSA C227.3

ANSI/IEEE C57.12.20, C5712.38, CS7.12.90


  • Compact Design
  • High Efficiency
  • Robust Construction
  • Versatile Voltage Options
  • Advanced Safety Features
  • Ease of Installation and Maintenance


  • Standard single phase pad mounted transformer lead time is 8-10 weeks;
  • It takes more than ten weeks for special specifications and designs.

Daelim Single Phase Pad Mounted Transformer Catalog Download 

DAELIM Transformer Certificates


Daelim is a professional transformer supplier. There are 20 years of transformer design, production, and export experience. Daelim design and production of multi-standard SINGLE PASE PAD MOUNTED Transformers, such as IEEE/ANSI, CSA, DOE, IEC, etc. Transformer with Ul/Cul, CSA, IEEE, SGS, and other product certificates and test reports.

The delivery time of the Daelim'single phase pad mounted transformer is 6-8 weeks. Transformers are in stock for your urgent needs. Contact Daelim for the single pad-mounted transformer stock information.

You may enjoy: Single Phase Pad Mounted Transformer For USA Utility

Design and production standards


The DOE standard mainly involves the efficiency value of the transformer. Mainly for the US market. In the United States, its capacity is less than 2500kva, the voltage is less than 34.5kV, and the output voltage is lower than 600V. It must meet the DOE efficiency value.


The following table is the DOE efficiency requirement for single phase pad mounted transformer:

75kva residential transformer























This standard is mainly the requirement for the Canadian market. Mainly specifies the requirements for single-phase pad-mounted distribution transformers with separable insulated high-voltage connectors.


This Standard applies to single-phase, pad-mounted, 60 Hz, liquid-filled distribution transformers with separable insulated high-voltage connectors designed for operating on an effectively grounded wye system, rated at 167 kVA or less, with an insulation class of 18 kV or less, and suitable for mounting outdoors on pads without additional protective enclosures.


This standard is mainly suitable for equipment that effectively grounded underground power distribution systems. A secondary distribution voltage of 240/120 V.

Rated high voltage(V)250kva single phase pad mounted transformer


8 320GrdY/4800






The kVA ratings at rated voltages shall be 25, 50, 75, 100, and 167.

Single-phase pad mount transformers cool down only through oil liquid; Do not use external cooling devices, such as heat sinks, radiators, etc.


The single pad mount transformer test is by the requirements of ANSI/IEEE C57.12.90.The color shall be either seafoam green, Munsell 4.82 G 4.07/3.35, or equipment green, Munsell 9GY1.5/2.6.


Transformers may be provided with the following optional items if specified by the purchaser:

(a) an anticorrosion skirt for highly contaminated areas;

(b) drain plug and filler plug;

(c) load-break switches;

(d) provision for padlocking of load-break switches;

(e) stud-type or spade-type low-voltage bushings;

(f) load-break inserts complete with dust cap;

(g) bail tabs on the well-bushing clamps

(h) high-voltage taps;

(i) an impulse test

(j) minimum impedance to limit the short-circuit current at the service equipment as follows:

(i) 75 kV•A: 2.0%; and

(ii) 100–167 kV•A: 2.5%;

(k) oil level sight gauge located to ensure safe operation of the load-break switches; 

(l) fire-resistant fluid in place of oil. Transformers with fire-resistance fluid shall be designated KNAN or LNAN.




This part of IEC 60076 applies to oil-immersed transformers.

Suitable for distribution transformer power rating with a maximum rating of 833kVA single phase.


Single Phase Pad Mounted Transformer Detail

100kva single phase pad mouonted transformerThe single-phase pad-mounted transformer(residential transformer) of Jiangsu Daelim Electric Co., Ltd. is designed to improve
performance in terms of kVA rating, compact dimensions, lighter weight, safety, and sustainability. No distribution room can be directly placed indoors or outdoors, it can also be placed in the streets and the greenbelt and reliably ensure personal safety, both power supply facilities, and also decorate the environment. Widely used in residential areas, commercial centers, stations, airports, factories, businesses, hospitals, schools, and other places. It is a low-profile,compartment-type transformer, which is suitable for mounting outdoors on pads without additional protective enclosures and meets the following standards: IEC60076, ANSI/IEEEC57.12.00, C57.12.20, C57.12.38, C57.12.90, CSA, etc.

A single-phase transformer inputs single-phase AC power and outputs single-phase AC power, but it can only provide single-phase power for loads that require single-phase power. If three single-phase transformers are connected, they can also provide three-phase power like a three-phase transformer.

Learn more: 3 Phase Pad Mounted Transformer-Daelim Transformer


A single-phase transformer generally means that the primary coil is designed according to a single-phase single-coil, and the secondary can have one or more winding coils. Ideally, the total secondary power is about or equal to the total primary power. For example, the common primary connected to the low voltage of the mains is 220 volts, and its iron core is made into a mouth shape, a Japanese shape, a ring, and an R shape.

Standard Features

*  Quality System ISO 9001 certified

*  Meet DOE Energy Efficiency Standard or exceeds ANSI/IEEE and NEMA standards

*  Tank coating exceeds IEEE Std C57.12.28™-2005 and IEEE Std

C57.12.29™-2005 standards (stainless steel units only)

*  Full compliance with IEEE Std C57.12.28™-2005 standard enclosure integrity requirements

*  Pressure relief device

*  Fluid fill and drain provisions

* Laser-engraved nameplate

*  Floating lock pocket for easy alignment

*  Decal bushing designations

*  Welded domed tank cover

*  Tamper strips of noncorrosive material

*  Crowned tank

*  Removable sill

*  Hinged door with stainless steel hinge pins and barrels

*  Ground strap from X2 to tank ground

*  HV bushing wells for dead front elbow connectors

*  High-voltage bushing wells - 200 A and low-voltage bushing


Single-phase Pad-mounted Transformer Specification

Single phase Pad mounted Transformer Specification
High voltage(kV) No Load Loss On load Loss Height
Oil Weight(kg) Total Weight(kg)
15 kVA 34.5/19.92
or others
50 195 840 740 610 45 294
25 kVA 80 290 840 740 610 68 362
37.5 kVA 106 360 840 760 610 75 476
50 kVA 135 500 840 810 610 93 553
75 kVA 190 650 840 860 610 132 672
100 kVA 280 1010 910 1200 965 230 714
167 kVA 435 1530 1000 1200 965 265 913
250 kVA 550 2230 1250 1300 1430 325 1106

Get it now: 167 kVA Transformers: The Ultimate FAQ Guide


Single phase Pad-mounted Transformer Main Accessories:

single phase padmounted transformer
HV Bushings*2

LV Bushings*3

Tap Changer*1

Bay-O-Net Fuse*1

ELSP Fuse*1

Oil Level Gauge*1

Pressure Relief Valve*1


Fill Plug*1

Drain Valve*1

Ground Strap Copper*1

Grounding Spade Terminal*2

All accessories of Single Phase Pad Mounted Transformer can be selected according to to needs, not all accessories are necessary.




•  Multiple voltages or taps

• Externally operable multiple voltages or tap changer switches for

safe operation

•  Stainless steel tank, tank bottom, sill, door, and/or hardware

•  Service entrance in the sill

•  Various spades and terminals available for secondary bushings

•  Various other designations available, e.g., kVA, voltages, fuse number

•  High-voltage bushing inserts

•  Ground connectors

• One piece high-voltage bushings

Envirotemp™ FR3™ fluid

• Load break switches

• Drain/sampling valve

• Pressure vacuum gauge

• Liquid level gauge

• Temperature gauge

• Canadian Standards Association (CSA) and Consumer Electronics Association (CEA) design stage bushing


Single-phase Pad-mounted Transformer Diagram

Here is a reference drawing of 167KVA-24.94Y-14.4KV/0.24(0.12)V single-phase pad-mounted transformer. From this drawing, you can see the information such as sizes, weight, parts list, diagram of connecting, etc...

Learn more about Transformer Diagram

pad-mounted transformer diagram
After confirming the advance payment from you, the Daelim engineer team will prepare the production drawing for the customer and send it to you for confirmation. Once we receive the signed drawing from you, the Daelim factory will start to purchase the materials and manufacture them. Moreover, you can see the production progress and situation of the transformer on our website.

You may enjoy: 25kVA Transformer: The Ultimate FAQs Guide - Daelim





Daelim Belefic performs routing testing on each transformer manufactured including the following tests:

  • Ratio, Polarity, and Phase Relation: Assures correct winding ratios and tap voltages; checks insulation of HV and LV circuits. Checks the entire insulation system to verify all live-to-ground clearances.
  • Resistance: This test verifies the integrity of internal high-voltage and low-voltage connections; and provides data for loss upgrade calculations.
  • Applied Potential: Applied to both high-voltage and low-voltage windings, this test stresses the entire insulation system to verify all live-to-ground clearances.
  • Induced Potential: 3.46 times normal plus 1000 volts for reduced neutral designs.
  • Loss Test: These design verification tests are conducted to ensure that guaranteed loss values are met and that test values are within design tolerances. Tests include no-load loss and excitation current along with impedance voltage and load loss.
  • Leak Test: Pressurizing the tank to 7 psig assures a complete seal, with no weld or gasket leaks, to eliminate the possibility of moisture infiltration or fluid oxidation.
  • Operation tests of all devices: All electrical and electro-mechanical devices shall be operated both in auto and manual mode for proper sequencing/staging and function.



The design performance tests include the following:

  • Temperature Rise: Our automated heat run facility ensures that any design changes meet ANSI® and IEEE® temperature rise criteria.
  • Audible Sound Level: Ensures compliance with NEMA® requirements.
  • Lightning Impulse: To assure superior dielectric performance, this test consists of one reduced wave, two chopped waves, and one full wave in sequence, precisely simulating the harshest conditions.
  • The performance tests such as short-circuit capability tests, and lifting and moving devices tests can be executed while specified by the customer

Learn more about Pad Mounted Transformer

Daelim Single Phase Pad-mounted Transformer Test Report

Each single-phase pad-mounted transformer produced by Daelim must conduct strict factory tests. Only after the test results meet the standards are they packaged and shipped.

The following table is a factory test report for the Daelim 14.4 kV 100 kVA single-phase pad-mounted transformer.

ZGD-H-100kVA/14.4kV/0.24kV(0.12)Transformer Test Report
Rated Capacity 100 Product Type ZGD-H- 100/14.4/0.24(0.12) 60HZ Factory  Serial No. DL2201026
3Voltage Combination HV(kV) 14.4 Current HV 6.94 Polarity Ii6
LV(kV) 0.24 LV 416.67
2 、 Measurement of voltage ratio
Tapping Position HV and LVThe Voltage Value of the Test The Grade and Accuracy:QJ3 5A
Grade 0.2
HV(kV) LV(kV) HV/LV(%)
1 15120 240 0.00
2 14760 0.00
3 14400 0.00
4 14040 0.00
5 13680 0.00
3 、 Measurement of winding resistance Routine)
Tapping Position Winding Resistance Measurement KV-HV (Ω) LV(Ω)
1 4.773 x1x2(Ω) 0.002009
2 4.659
x2x3 (Ω) 0.001322
3 4.544
4 4.432
x1x3 (Ω) 0.002972
5 4.313
The Meter NO. and Grade of Accuracy BZC3395 Grade
Temperature 26℃ Humidity 46%
4、No-load loss and no-load current test.
Test Items No-Load Loss at rated voltage W No-Load Current %
Measured Value 252 0.37
5、Load loss and Short circuit test.
Test Items Load Loss at 85°C and rated voltage W Total Loss W Short Circuit Impedance at 85°C
Measured Value 946 1198 2.61
6 、 Applied voltage test
Power Frequency
withstand Voltage Test
Test Time 60 S
The Test Voltage(kV) 10
7、Induced Over Voltage Withstand Test
Induced Over Voltage
Withstand Test
0.48(rms) for L.V. bushing at 120HZ 60S
8 、 Insulation Resistance test
location Insulation Resistance( M Ω) at 15℃ R60
HV-E 0
LV-E >2500
9 、 Other Information.
The Active Parts
Weight of Lifting
The Weight of Insulation Oil Total Weight The Temperature Rise of the
Oil Pressure
310kg 311L kg <65K 40KV
10、Leakage test  Routine)
Test method Applied pressure(kPa) Duration(h) Residual pressure(kPa) Result
The static pressure
20 12 18 No leakage and no


Daelim Single Phase Pad-mounted Transformer Project Cases

Daelim Single Phase Pad Mountain Transformer has exported a lot to the North and South American markets, especially the United States and Canada. This type of transformer is mainly used in residential areas. It has the characteristics of low loss, small volume, safety, and environmental protection.


Residential transformer for the USA market

residential transformer usa

Residential transformer for the Canadian market

residential transformer canada

Click here to view more pad-mounted transformer project cases!

If you also need Single Pad Mountain Transformer or Residential Transformer, please contact the Daelim team to give the transformer solution within 24 hours.,, Tel/WhatsApp: +86-15801656761