I am trying to size a circuit breaker for a transformer.
The transformer is three phase 480 : 4160 V rated at 25 kVA. From my calculations there will be approximately 30 A on the primary and 3.5 A on the secondary winding.
Do the circuit breakers have to be voltage rated? Since the secondary winding is a medium voltage does that affect the type of breaker used?
I have found information on the NEC guidelines but I see that this is for the US is there any equivalent for the UK?
Will I need a circuit breaker for both the primary and the secondary winding?
Any help with this matter would be much appreciated.