A three phase pole mounted transformer is an outdoor distribution transformer designed to convert medium-voltage electricity into lower three-phase voltage for utility, commercial, agricultural, and industrial applications.
Unlike pad-mounted transformers installed at ground level, a 3 phase pole mounted transformer is installed on utility poles and connected directly to overhead distribution lines. This makes it especially suitable for rural electrification, utility distribution networks, farms, industrial facilities, and locations where ground space is limited.
Three phase pole mounted transformers are available in a wide range of capacities and voltage ratings. Common sizes include 75 kVA, 100 kVA, 150 kVA, 167 kVA, 225 kVA, 300 kVA, and 500 kVA, with customized designs available according to different utility standards.
This guide explains the common sizes, voltage ratings, specifications, applications, prices, and selection considerations for three phase pole mounted transformers.
What Is a Three Phase Pole Mounted Transformer?
A three phase pole mounted transformer is generally an Ölverteilertransformator installed outdoors on a single-pole or multi-pole support structure.
Its main function is to step down medium-voltage distribution power, such as:
- 11 kV → 400/230 V
- 12.47 kV → 208Y/120 V
- 12.47 kV → 480Y/277 V
- 13.2 kV → 480Y/277 V
- 13.8 kV → 220Y/127 V
- 13.8 kV → 480Y/277 V
- 24.9 kV → 480Y/277 V
- 34.5 kV → 480Y/277 V
The exact voltage combination depends on the local utility network and project requirements.
Most pole mounted distribution transformers use ONAN (Öl Natur Luft Natur) cooling and can be manufactured with either copper or aluminum windings.

Common Three Phase Pole Mounted Transformer Sizes
Transformer capacity is normally expressed in kVA. The correct rating depends on the connected load, expected demand, future expansion, and utility requirements.
| TRANSFORMER SIZE | TYPICAL APPLICATIONS |
|---|---|
| 45–75 kVA | Farms, small commercial loads, rural distribution |
| 100 kVA | Commercial buildings and community distribution |
| 150 kVA | Commercial and light industrial applications |
| 167 kVA | Utility, commercial and industrial distribution |
| 225 kVA | Industrielle und gewerbliche Einrichtungen |
| 300 kVA | Factories and larger distribution loads |
| 500 kVA | Industrial and utility distribution |
| 750 kVA+ | Specialized high-capacity overhead applications |
Larger transformers require careful consideration of the total transformer weight, pole structure, installation method, and local utility requirements.
For some high-capacity applications, a Aufbautransformator or ground-mounted transformer may be more suitable.
167 kVA Three Phase Pole Mounted Transformer
Die 167 kVA Transformator is an interesting capacity for utility and distribution applications and can be manufactured as a three-phase pole mounted transformer according to the required electrical system.
Eine typische 167 kVA three phase pole mounted transformer may have specifications such as:
| PARAMETER | TYPICAL SPECIFICATION |
|---|---|
| Nennkapazität | 167 kVA |
| Phase | Dreiphasig |
| Primäre Spannung | 12.47 kV / 13.2 kV / 13.8 kV |
| Sekundäre Spannung | 208Y/120 V / 220Y/127 V / 480Y/277 V |
| Frequenz | 50 Hz / 60 Hz |
| Material der Wicklung | Kupfer oder Aluminium |
| Kühlung | ONAN |
| Einrichtung | Outdoor Pole Mounted |
| Isolierendes Medium | Mineral Oil or Alternative Fluid |
| Stufenschalter | Off-Circuit |
| Normen | ANSI / IEEE / IEC / CSA as required |
For example, a project may require a 167 kVA transformer, 13.8 kV primary and 480Y/277 V secondary, 60 Hz, three phase, copper winding and ONAN cooling.
However, specifying only “167 kVA transformer” is not sufficient for manufacturing. Primary voltage, secondary voltage, phase, frequency, winding material, connection, BIL, applicable standard, and installation conditions should also be provided.

Common Voltage Ratings
Three phase pole mounted transformers can be designed for different utility distribution systems.
Primäre Spannung
Common primary voltage ratings include:
4.16 kV, 6.6 kV, 10 kV, 11 kV, 12.47 kV, 13.2 kV, 13.8 kV, 22 kV, 24.9 kV, 33 kV and 34.5 kV.
Sekundäre Spannung
Common secondary voltage ratings include:
208Y/120 V, 220Y/127 V, 380Y/220 V, 400Y/230 V, 415Y/240 V and 480Y/277 V.
Custom voltage combinations can also be manufactured according to the grid and end-user requirements.
Key Technical Specifications
When purchasing a three phase pole mounted transformer, several specifications should be confirmed.
Copper or Aluminum Windings
Both copper and aluminum are widely used for distribution transformer windings.
Copper windings provide high electrical conductivity and good mechanical strength, while aluminum windings can offer a more economical and lighter solution.
The winding material should be clearly specified in the RFQ.
Methode der Kühlung
Most oil-immersed pole mounted transformers use ONAN cooling. Natural circulation of insulating oil transfers heat from the windings and core to the tank, where it is dissipated into the surrounding air.
Stufenschalter
An off-circuit tap changer is commonly provided to compensate for variations in the incoming voltage.
A typical tap range is:
±2 × 2.5%
Other tap configurations can be provided according to utility specifications.
Verbindung
Common transformer connections include Delta-Wye, Wye-Wye and Delta-Delta.
Zum Beispiel:
Primary: 13.8 kV Delta
Secondary: 480Y/277 V Grounded Wye
IEC projects may instead specify vector groups such as Dyn11, Dyn1 or Yyn0.
BIL
For ANSI/IEEE projects, the Basic Impulse Insulation Level (BIL) is an important specification.
The required BIL depends on the system voltage and utility standard. It should be confirmed before the transformer design is finalized.

Applications of Three Phase Pole Mounted Transformers
Three phase pole mounted transformers are widely used in:
- Verteilungsnetze der Versorgungsunternehmen
- Ländliche Elektrifizierung
- Kommerzielle Gebäude
- Farms and agricultural facilities
- Irrigation and pumping stations
- Industrial workshops
- Manufacturing facilities
- Bergbauprojekte
- Wohnanlagen
- Öffentliche Infrastruktur
- Projekte für erneuerbare Energien
They are particularly useful where the electrical distribution network uses overhead medium-voltage lines.
Three Phase vs Single Phase Pole Mounted Transformer
A Einphasen-Masttransformator is commonly used for residential and small rural loads, while a three phase pole mounted transformer is better suited for larger commercial and industrial loads.
| FEATURE | SINGLE PHASE | THREE PHASE |
|---|---|---|
| Electrical Supply | Einphasig | Dreiphasig |
| Typical Loads | Residential, small rural | Commercial, industrial |
| Motor Applications | Begrenzt | Well suited |
| Kapazität | Usually smaller | Usually larger |
| Bauwesen | Simpler | More complex |
For facilities operating three-phase motors, pumps, HVAC equipment, or industrial machinery, a three phase transformer is generally the appropriate solution.
Pole Mounted Transformer vs Pad Mounted Transformer
The main difference is the installation method.
A Masttransformator is installed above ground and normally connected to overhead distribution lines.
A Aufbautransformator is installed on a concrete foundation and is commonly connected to underground distribution cables.
Pole mounted transformers are particularly suitable when:
- The existing network uses overhead lines
- Ground space is limited
- A simple utility distribution arrangement is required
Pad mounted transformers are generally preferred for underground distribution systems, commercial developments, residential communities, and applications requiring enclosed HV/LV compartments.

Three Phase Pole Mounted Transformer Price
Die three phase pole mounted transformer price varies significantly depending on the technical configuration.
The main cost factors include:
- Transformer capacity (kVA)
- Primär- und Sekundärspannung
- Wicklungen aus Kupfer oder Aluminium
- Insulating fluid
- BIL
- Transformer losses and efficiency
- Bushings and terminals
- Stufenschalter
- Surge arresters and protection
- ANSI/IEEE, IEC or CSA requirements
- Menge
- Destination and shipping cost
For example, the price of a 75 kVA pole mounted transformer will be considerably different from a customized 167 kVA or 300 kVA three phase pole mounted transformer.
Similarly, a transformer designed for 13.8 kV / 480Y/277 V under ANSI/IEEE requirements may have a different cost from an IEC-designed 11 kV / 400 V transformer.
Therefore, an accurate transformer price should be based on the complete project specification rather than only the kVA rating.
How to Select a Three Phase Pole Mounted Transformer
Before requesting a quotation, confirm the following information:
Nennkapazität: 75 kVA, 100 kVA, 167 kVA, 225 kVA, 300 kVA, etc.
Primärspannung: 11 kV, 12.47 kV, 13.8 kV, 24.9 kV, etc.
Sekundäre Spannung: 208Y/120 V, 400/230 V, 480Y/277 V, etc.
Häufigkeit: 50 Hz oder 60 Hz
Material der Wicklung: Kupfer oder Aluminium
Connection: Delta/Wye or required vector group
Einbau: Outdoor Pole Mounted
Applicable Standard: ANSI/IEEE, IEC, CSA or local utility standard
Umweltbedingungen: Temperature, altitude and pollution level
Quantity and Destination: Required for production and freight calculation
Providing these parameters allows the transformer manufacturer to select the correct electrical design, insulation level, dimensions, weight, accessories, and price.

Häufig gestellte Fragen
What sizes are available for three phase pole mounted transformers?
Common ratings include 45 kVA, 75 kVA, 100 kVA, 150 kVA, 167 kVA, 225 kVA, 300 kVA and 500 kVA. Other capacities can be customized.
Is a 167 kVA transformer available in three phase?
Yes. A 167 kVA Transformator can be designed as a three phase pole mounted distribution transformer. The primary voltage, secondary voltage, frequency, winding connection and applicable standard should be specified.
Can a pole mounted transformer have copper windings?
Yes. Three phase pole mounted transformers can be manufactured with either copper or aluminum windings.
What is the typical cooling method?
Most oil-immersed pole mounted transformers use ONAN (Öl Natur Luft Natur) cooling.
What information is required for a quotation?
At minimum, provide the kVA rating, primary voltage, secondary voltage, phase, frequency, winding material, quantity, applicable standard and destination country.
Three Phase Pole Mounted Transformer Manufacturer
A reliable three phase pole mounted transformer should be designed according to the actual electrical network, load requirements, environmental conditions and applicable utility standards.
Evernew-Transformator manufactures customized power and distribution transformers for international utility, industrial, commercial and infrastructure projects. Our transformer range covers 6 kV bis 500 kV, with solutions including three phase pole mounted transformers, single phase pole mounted transformers, pad mounted transformers, oil-immersed distribution transformers, dry type transformers and large power transformers.
Whether your project requires a 75 kVA, 100 kVA, 167 kVA, 225 kVA, 300 kVA or 500 kVA three phase pole mounted transformer, the voltage, winding material, connection, frequency and accessories can be customized according to project requirements.
For a quotation, send us your required kVA, primary and secondary voltage, frequency, winding material, quantity and destination.
Evernew Transformer – Professional Power & Distribution Transformer Manufacturer in China

