Transformer feed

[Davebones]

Have a 3 Phase 480V to 120-208V 75KVA transfrormer that feeds a 150 amp main disconnect panel . We might add another panel on the transformer . The 480V feed is only 80 amps .Is that a concern that the breaker is undersized for the primary as full load for the transformer at 480V is 90 amps ? Even if we add another panel the secondary load won't be over 50% .

 

[pete m.]

It doesn't sound like a concern that the NEC would address. If it becomes a concern you could always increase the size of the primary OCPD.

Pete