I would refer to the ASTM Standards for the information your looking for. Usually 32 to 36 kV per 1/8" gap is the minimum expected for new transformer oils. The testing method used however is subject to the precondition of the oil. Attached below for your reference is information from...
I believe NEC code 250-5 (b), Exception #3 applies. You do not need a ground. The exception is, "spparately derived systems supplied by transformers that have primary voltage rating less than 1000 volts, providing that all of teh following conditions are met:
a) System is used for control...
The total connected load applied to most transformers in the range of 1500 kVA would exceed the nameplate rating of the transformer. This is normal. There is considerable diversity in the load attached to a transformer. Depending on the type of load, i.e., electric heat, motors, induction...
I have about the same experience as NormGA in that Ihave been a System Maintenance Engineer for 26 years working on and with substation equipment. If your transformer has sudden pressure relays (SPR) on it they can and should be tested. The overpressure relief device you are speaking of is...
Steve58,
The process of operating on site generation for your building is considerable and can be very expensive. Part of your decision to own and operate a plant should be based on the economics of doing so. If your utlilty supplies you with power using a rate charge that is based on...