Pole Mounted Transformers: Delivering Power Where It's Needed.
01 General
1.1 Project Description
A 75 kVA single phase pole mounted transformer was delivered to Canada in 2025. The rated power of the transformer is 75 kVA with ONAN cooling. The high voltage is 24.94GrdY/14.4 kV with ±2*2.5% tapping range (NLTC), the low voltage is 0.48/0.277 kV, and they formed a vector group of Ii6.
As a critical link connecting the high-voltage power grid to end-users, the single phase pole mounted transformer plays an indispensable role in daily electricity supply for residential, rural, and small-scale commercial scenarios. Unlike large-scale substation transformers, it is installed directly on utility poles, allowing flexible deployment in areas with limited space-such as along residential streets, rural roads, or near small shops and farmhouses. By efficiently stepping down high-voltage electricity to safe, usable low voltage, it powers household appliances, agricultural machinery, and small commercial equipment, directly supporting daily life and local economic activities. With advantages of easy maintenance, low operational noise, and strong resistance to harsh weather (e.g., rain, dust, and temperature fluctuations), this transformer ensures a continuous power supply even in complex environments, making it a cornerstone of reliable and accessible electricity distribution for communities worldwide.
1.2 Technical Specification
75 kVA pole mounted transformer specifications type and data sheet
| Delivered to | Canada |
| Year | 2025 |
| Type | Pole mounted transformer |
| Standard | CSA C2.2-06 |
| Rated Power | 75 kVA |
| Frequency | 60HZ |
| Phase | 1 |
| Polarity | Additive |
| Cooling Type | ONAN |
| Primary Voltage | 24.94GrdY/14.4 kV |
| Secondary Voltage | 0.48/0.277 kV |
| Winding Material | Copper |
| Angular displacement | Ii6 |
| Impedance | ≥1.5% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 0.165 kW |
| On Load Loss | 1.05 kW |
1.3 Drawings
75 kVA pole mounted transformer diagram drawing and size.
02 Pole Mount Transformers Parts
2.1 L.V. Bushing – BIL: 30 KV; L.V. Ground Provision
| The low-voltage bushings are rated for a 30 kV BIL, which is more than enough for the LV side of a 75 kVA unit and provides a comfortable insulation margin. The LV ground provision is placed right beside it, making the neutral grounding straightforward and compliant. Operators can access it easily during installation. |  |
2.2 H.V. Bushing – BIL: 125 KV
 | On the high-voltage side, the bushings meet a 125 kV BIL. This rating is standard for Canadian distribution levels and gives the transformer solid protection against lightning impulses. It’s a simple component, but it carries significant responsibility in real grid conditions. |
2.3 Cover Ground Strap
| A grounding strap is fitted across the tank cover. Its job is to keep all metal parts at the same potential, even if there are slight movements or maintenance operations. It’s a small detail, but it ensures the cover and the tank remain electrically bonded at all times. |  |
2.4 Grounding Connector
 | The grounding connector is mounted near the base. It provides a firm point for the station ground conductor, and utilities usually prefer this layout for quick installation. Once connected, it helps maintain a stable ground path during faults. |
2.5 Lifting Lugs; Tapchanger; Pressure Relief Valve
| The lifting lugs are welded onto the tank and sized properly for the transformer’s weight, so handling the unit with a crane is straightforward. The no-load tapchanger offers a ±2 × 2.5% adjustment on the HV winding; nothing complicated, just enough flexibility to match line voltage. The pressure relief valve is also present on the tank top. In abnormal pressure situations, it opens automatically to keep the tank safe. |  |
03 Testing
The test for the 75kVA-14.4/0.277kV single phase pole mounted transformer was conducted on 2025-04-25 (ambient temp: 23.9℃, RH: 36%) in line with CSA C2.2-06(R2022) and CSA C802.1-13(R2022). Routine tests included winding resistance (HV: 9.747-10.786Ω, LV: 5.875mΩ), ratio test (deviation +0.02~+0.06%, vector group Ii6), polarity (Additive), no-load loss/current (128.9W/0.19% at 100%, 148.6W/0.23% at 105%), load loss/impedance (912W at 85℃, impedance 2.21%, efficiency 99.11% ≥98.94%), voltage withstand (LV 10kV/60s, induced 0.554kV/240Hz/30s, no voltage collapse), insulation resistance (max 15.7GΩ), 20kPa/12h leak test (no leakage), and oil test (dielectric strength 53.9kV). All passed; the report cannot be copied without SCOTECH’s permission, objections must be raised within 7 days, and it is invalid without tester/verifier/approver signatures.
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | / | / | / | Pass |
| 2 | Ratio Tests | / | The deviation of voltage ratio on the principal tapping: ±0.5% Connection symbol: Ii6 | +0.02~+0.06 | Pass |
| 3 | Polarity tests | / | Additive | Additive | Pass |
| 4 | No-load losses and excitation current | % | I0 :: provide measured value（100%） | 0.19 | Pass |
| kW | P0: provide measured value（100%） | 0.1289 | |||
| % | I0 :: provide measured value（105%） | 0.23 | |||
| kW | P0: provide measured value（105%） | 0.1486 | |||
| / | the tolerance for no load loss is +0% | / | |||
| 5 | Load losses , impedance voltage,total losses and efficiency | / | t:85℃ the tolerance for impedance is ≥1.5% the tolerance for total load loss is +0% | / | Pass |
| % | Z%: measured value | 2.21 | |||
| kW | Pk: measured value | 0.912 | |||
| kW | Pt: measured value | 1.041 | |||
| % | Efficiency not less than 98.94% | 99.11 | |||
| 6 | Applied Voltage Test | / | LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | / | Applied voltage (KV):0.554 | No collapse of the test voltage occurs | Pass |
| Duration(s):30 | |||||
| Frequency (HZ): 240 | |||||
| 8 | Insulation Resistance Measurement | GΩ | LV-HV to Ground | 15.7 | Pass |
| HV&LV to Ground | 13.3 | ||||
| 9 | Leakage Test | / | Applied pressure：20kPA | No leakage and no Damage | Pass |
| Duration：12h | |||||
| 10 | Oil Test | kV | Dielectric Strength | 53.9 | Pass |
| mg/kg | Moisture Content | 7.4 | |||
| % | Dissipation Factor | 0.157 | |||
| mg/kg | Furan Analysis | ≤0.1 | |||
| / | Gas Chromatography Analysis | / |
04 Packing and Shipping
4.1 Packing
| The single phase pole mounted transformer is packaged in a sturdy wooden case. The case is custom-sized to fit the transformer’s dimensions, providing reliable protection against external shocks, minor impacts, and moisture during transportation and storage. It ensures the transformer remains stable and intact until on-site installation. |  |
4.2 Shipping
 | For the single phase pole mounted transformer, transportation follows the CIF term with EDMONTON as the destination port. The seller is responsible for booking ocean shipping space, delivering the wooden-case-packaged transformer to EDMONTON Port, and bearing freight and cargo insurance costs to cover potential transit risks. Upon the transformer’s arrival at EDMONTON Port, the buyer receives the goods, while the risk of the transformer has already passed to the buyer when it left the loading port’s ship’s rail. |
05 FAQ
01. What Is a Single-Phase Pole-Mounted Transformer and What Is It Used For?
02. What Is the Typical Capacity Range of a Single-Phase Pole-Mounted Transformer?
Some suppliers can offer larger sizes if required, though once the rating gets high enough, users tend to move to three-phase or pad-mounted designs instead. It’s simply more practical at that point.
03. What Are the Advantages Compared With a Three-Phase Transformer?
There are several, and they’re fairly well recognized in distribution practice:
Shorter low-voltage feeders, which means lower losses.
By placing the transformer closer to the load, utilities can reduce voltage drop and improve efficiency in day-to-day operation.
A compact structure that requires almost no land.
No concrete pad, no fencing, and no enclosure. The pole itself becomes the support structure, which keeps installation simple.
Easier installation and maintenance.
Technicians can access and replace these units more quickly than underground or pad-mounted equipment, which saves time-especially during fault recovery.
Overall, it’s a practical choice when the load is moderate and the installation area is tight or widely spread out.
04. What Installation or Maintenance Points Should Be Noted?
A few things matter here, and while none of them are complicated, they’re important for long-term reliability.
Use a pole with sufficient strength. It must support the transformer safely and stay stable in wind and weather.
Keep all terminals and connectors clean and well-prepared. Dirt, oil, or poor contact can cause problems later. Conductors also need enough flexibility to cope with temperature swings or vibration.
Check the oil level, oil condition, and bushings regularly if the unit is oil-filled. Any sign of leakage or insulation damage should be dealt with early.
Verify that grounding is solid. A good, low-resistance ground path is critical for safety.
Perform an annual visual inspection. Look for corrosion, deformation, oil stains, or bushing contamination.
Carry out oil testing and bushing cleaning every 2–3 years, or more frequently in harsh climates such as coastal or industrial zones.
