In Art 450 (b) it states for 600v nom or less 125% over current protection IF REQUIRED
Where does it state when it is required?
I have also protected the primarty side of a transformer according to the KVA rating. Ex. 75KVA 480v-208/120v I would use 90a over-current protection for primary side.
Is this necessary? I was always of the understanding that w/out primary protection, if the secondary side is protected correctly, you could burn the transformer.
Ex. using transformer in previous example, I would use 200a protection on secondary side.
Am I wrong?
I have been seeing alot of small transformers in office suites, with say 9KVA, 15KVA with fuse protection way to high. Primary fuses I have seen 50a for these. Yet transformer shows no sign of burning.
Can more amps be induced through a transformer, than the windings alow?
I cnat beleive I asked this, but I am not sure now. It has been 10 years since my electrical theory school days.
[This message has been edited by ayrton (edited 10-26-2006).]
