Article 130.3 Exception No. 1

Exception No. 1 (2) states that one of the conditions where an arc flash hazard analysis is not required is where the circuit is fed by one transformer.

This question may be nit picky or reading too much into that statement but in mind when I see that one transformer is mentioned, I think of a 3 phase single transformer. However, I have seen many facilities fed by an overhead service from the utilities 3 phase transformer bank consisting of 3 single phase transformers.

Does a 3 phase transformer bank, consisting of 3 single phase transformers, meet Exception No. 1 (2) of one transformer?

Three single phase transformers in a bank have the same electrical characteristics as 1 - 3 phase transformer of equal size.

ex...3-100 kVA single phase transformers = 1-300 kVA three phase transformer.

I believe it only applies to 240 volts or less and <125 kVA.

Alan

Exception No. 1: An arc flash hazard analysis shall not be required where ALL of the following conditions exist:
(1)
(2)
(3)

ALL of the conditions listed must exist.