Transformer Impedance Fault Current Calculator
Transformer impedance limits secondary fault current. The short-circuit calculator uses kVA, secondary voltage and percent impedance to estimate available current.
transformer impedance fault calculator transformer impedance fault current calculator fault current at transformer secondary calculator
Full-load current
I_FL = kVA * 1000 / (phase_factor * V)
Infinite-bus fault current
I_SC = I_FL / (Z_percent / 100)
What changes the result
Known upstream source impedance and downstream feeder impedance lower available fault current at the checked point.
Related pages
- Transformer kVA calculator - load kVA, design margin and standard size rounding.
- Conduit fill calculator - raceway fill from conductor count, area and conduit size.
- Voltage drop calculator - feeder voltage drop and conductor-size screening.
- Short-circuit current calculator - available fault current from transformer impedance.