The 250 kVA single-phase pole-mount distribution transformer is an overhead unit built for utility and rural distribution service. It hangs from a single pole or crossarm bracket and steps medium-voltage primary down to a 277 or 480 V secondary. At 250 kVA this is a heavy overhead unit. Confirm pole and crossarm capacity before specifying – ratings above 167 kVA are frequently supplied pad-mounted or platform-mounted instead.
Specifications
| Rating | 250 kVA |
|---|---|
| Phase | Single phase |
| Primary voltage class | 15kV / 25kV / 35kV |
| Secondary voltage class | 240V / 600V |
| Basic insulation level (BIL) | 95 kV / 125 kV / 150 kV |
| Frequency | 60 Hz |
| Temperature rise | 65 °C |
| Winding material | Aluminum |
| Insulating fluid | Mineral oil, Type I |
| Cooling class | ONAN |
| Taps | Plus/minus 2 x 2.5% full-capacity below and above nominal |
| Enclosure | Munsell Green 7GY3.29/1.5, tamper-resistant |
| Feed configuration | Per application |
| Standards | ANSI/IEEE C57.12, NEMA, DOE 2016 efficiency |
| Lead time | As little as 10 weeks |
Full-load current
Rated secondary current for a 250 kVA unit at each available secondary voltage. Use these figures for conductor, breaker and bus sizing.
| Secondary voltage | Full-load current |
|---|---|
| 120/240 | 1,042 A |
| 240/480 | 521 A |
| 277 | 903 A |
| 480 | 521 A |
Rated primary current at each available primary voltage:
| Primary voltage | Full-load current |
|---|---|
| 2400 | 104 A |
| 4160GrdY/2400 | 104 A |
| 4800 | 52 A |
| 7200 | 35 A |
| 7620 | 33 A |
| 12000 | 21 A |
| 12470GrdY/7200 | 35 A |
| 13200GrdY/7620 | 33 A |
| 13800GrdY/7970 | 31 A |
| 14400 | 17 A |
| 19920 | 13 A |
| 22900GrdY/13200 | 19 A |
| 24940GrdY/14400 | 17 A |
| 34500GrdY/19920 | 13 A |
Typical applications
- Multi-unit residential
- Industrial single-phase process loads
- Overhead utility distribution on heavy-load feeders
- Large single-phase commercial services
Construction
Standard construction is aluminum windings in a sealed tank with mineral oil, ONAN cooled, 65 °C rise. The tank is welded and finished in Munsell Green 7GY3.29/1.5. A four-position no-load tap changer provides plus and minus two 2.5% full-capacity taps. Copper windings and natural ester fluid are available on request.
Standards and compliance
- Built to ANSI/IEEE C57.12 and applicable NEMA standards
- Meets DOE 2016 efficiency requirements
- Factory test report supplied with every unit
- Manufactured and supported by Bear Power Solutions, Brandon, Mississippi
Frequently asked questions
What voltages is the 250 kVA available in?
The 250 kVA is available with 15kV / 25kV / 35kV primary and 240V / 600V secondary. That is 56 configurations in total. Every voltage inside a class carries the same price and the same basic insulation level.
What is the lead time on a 250 kVA?
Lead times start at 10 weeks from order confirmation, depending on configuration and current factory loading. Non-standard voltages, accessories, custom enclosure work and non-standard fluid or winding material extend that. Confirm the delivery date with Bear Power Solutions before committing to a project schedule.
Can this transformer be pad-mounted instead of pole-mounted?
Bear Power Solutions supplies equivalent ratings in pad-mount configuration. Pole-mount units above 167 kVA are heavy enough that pole and crossarm capacity should be verified, and larger ratings are commonly supplied pad-mounted or platform-mounted instead.
Can the 250 kVA be supplied with copper windings or natural ester fluid?
Standard catalog construction is aluminum windings with mineral oil. Copper windings and natural ester fluid are available on request. Both affect price and lead time, so request a quotation for a non-standard build.
What standards does the 250 kVA meet?
Units are built to ANSI/IEEE C57.12 and applicable NEMA standards, and meet DOE 2016 efficiency requirements. Factory test reports are provided with every unit.
Sizing the 250 kVA
At its lowest available secondary voltage the 250 kVA draws 1,042 A at full load; at its highest it draws 521 A. That spread is what makes secondary voltage selection an installation-cost decision as much as an electrical one – the higher voltage cuts conductor size for the same delivered power.
Secondary current at this rating is high enough that parallel conductor runs or busway are normally required on the low-voltage side. Confirm the secondary termination arrangement and available bus space before ordering.
Request a quote
For a firm price on a 250 kVA in a specific voltage configuration, or for a non-standard build with copper windings, natural ester fluid or custom accessories, send the details below and Bear Power Solutions will respond with a written quotation.
