I_{ f.l.} = Full Load Amperes
I_{ S.C.} = Short Circuit Current
KVA = The KVA of your transformer, or bank of transformers
% ML = Percent Motor Load
E_{ L-L} = Voltage Line to Line
Z = Impedance
100 / Z = Multiplier

Three Phase Calculations:
(KVA X 1000) / (E_{ L-L} X 1.732) = Three Phase Full Load Amps, I_{ f.l.}
100 / Z = Multiplier
I_{f.l.} X Multiplier = Transformer let thru Short Circuit Current, I_{ S.C.}
4 X FLA X % ML = Motor Load Contribution to Fault Current, I_{ S.C. motor cont.}
I_{ S.C.} + I_{ S.C. motor cont.} = Total Short Circuit Current, I_{ S.C. Total}

Single Phase Calculations:
(KVA X 1000) / E_{ L-L} = Single Phase Full Load Amps, I_{ f.l.}
100 / Z = Multiplier
I_{f.l.} X Multiplier = Transformer let thru Short Circuit Current, I_{ S.C.}
4 X FLA X % ML = Motor Load Contribution to Fault Current, I_{ S.C. motor cont.}
I_{ S.C.} + I_{ S.C. motor cont.} = Total Short Circuit Current, I_{ S.C. Total}