XFRMR Protection

[Alwayslearningelec]

75 KVA xfrmr( primary side 277/480- sec 120/208v). Primary side protect with 100A disconnect. Shouldn’t it be 150a?

Also, can you feed a 225A panel on the secondary side?

 

[david luchini]

75 KVA xfrmr( primary side 277/480- sec 120/208v). Primary side protect with 100A disconnect. Shouldn’t it be 150a?

It's not required to be 150A, though it certainly could be. Primary protection could be as large as 225A.

Also, can you feed a 225A panel on the secondary side?

Yes.

 

[infinity]

For 75 kva our typical setup is 125 primary, 225 secondary.

 

[jim dungar]

For 75 kva our typical setup is 125 primary, 225 secondary.

For decades the normal for our area was 100A primary, 200A secondary. Then manufacturers started offering 125A branch breakers, however many supply house are still only stocking 200A main breaker panels for the secondary.