electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Having a senior moment here. If I have a three phase transformer feeding a 120/208 single phase service, is the AFC calc just transformer three phase FLC / impedance?
Isn't this an easy one?Having a senior moment here. If I have a three phase transformer feeding a 120/208 single phase service, is the AFC calc just transformer three phase FLC / impedance?
Thank you. So no caveats being it is a three phase transformer with only two legs brought out? Only thing I can think of is that L-N fault will NOT be potentially 1.5 times higher than L-L like it typically is for single phase transformers.Assuming AFC is Arc-Fault Calculation, yes the short Circuit duty at the point of the fault would be the FLC (assuming this is the base current used in the per unit calculation) divided by the per unit impedance. If you are speaking of just the transformer, then the FLC/(%Z of the transformer/100) = Isc
Hope this helps.