[Carandorandy]

3 KVA dry type transformer (Calculating Overcurrent Protection on the Primary Side)?
I will run #12 THHN wire as we usualy do but the current on the load is some constant at about 1.5 amps for a low voltage power supply and the rest of the panel is floating at about 15 amps max using 480 single phase on the line side of the 3KVA.
Just wondering if I can calculate exactly what the transformer is going to draw?
Thanks
Carandorandy

 

[J. V.]

The xfmr will draw as much power as it can until it blows. Its like a motor. It's stupid.
You can figure the maximum amount of output with a given input. But you are not making much sense. It is either drawing 1.5 amps or 15 amps? Which is it?

line side calculated current = 6.25
Load side calculated current = unknown. no secondary voltage to calculate with.

You are really in the wrong forum. If you are an electrician go to www.electriciantalk.com. They are all professionals. This question does not belong in here. IMO.