Specifications include, but are not limited to: Distribution Transformer, single phase, 10kVA, pole mounted, with taps 2A – 2B 2.5% taps, with voltage rating of 7200/12470Y – 120/240V, Copper to Copper or Copper to Aluminum windings. All transformers offered for compliance with this specification are rated for use on 13200/22860Y or 22860GrdY/13200 V (25kV) or 7200/12470Y or 12470GrdY/7200 V (15kV) nominal voltage systems and are of oil-immersed, self cooled, sealed tank construction, and must be designed for operation at 60 hertz. All transformers rated 25kV shall have 125kV BIL and all transformers rated 15kV shall have 95kV BIL primary windings and bushings. They must be capable of delivering rated KVA continuously without exceeding the rated winding temperature rise of 65°C in an average ambient temperature of 30°C for any 24 hour period where the maximum ambient temperature does not exceed 40°C. Dual voltage units shall have an externally operable dual voltage switch on the side of the tank for de-energized operation