PFC Calculator
PFC Calculator

PFC Fault Current Calculator

Calculate the PFC kA from Zs

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Fault Current Calculator



PFC or Prospective Fault Current is a term used to describe the higher of either the prospective earth fault current (PEFC) and prospective short circuit current (PSCC).

Calculate the PFC fault current (kA & Amps) single phase and three phase PFC from the voltage and Ze or Zs earth loop impedance values.

- PFC PEFC PSSC fault current calculations with instant results!


  • Single Phase
  • Three  Phase
  • Fault Current kA
  • Impedance (Zs/Ze)


Here’s what some users of our PFC Calculator say,

PFC Calcualtor
Calculate PFC

Calculate PFC


To calculate PFC from Ze or Zs enter your voltage and Ze / Zs values and hit “Calculate”, the single phase and three phase PFC results will be displayed.


This PFC Calculator is extremely easy to use,  just enter any two values and hit “Calculate” to calculate the other.



  • PFC (Prospective Fault Current)
  • Zs / Ze (Earth Loop Impedance)
  • Volts (Voltage)


Enter any two values to calculate the other!

Calculate Voltage


To calculate the voltage from PFC enter your PFC and Ze / Zs values.



  • Uo = Voltage to Earth


Enter any two values to calculate the other!



What is PFC?

  • PSSC = Prospective Short Circuit Current : Single Phase = L-N Fault Current
  • PSSC = Prospective Short Circuit Current : Three Phase = L-L Fault Current
  • PEFC = Prospective Earth Fault Current : L-E Fault Current

PFC = Prospective Fault Current (The higher of PSSC or PEFC)


L = Live | N = Neutral | E = Earth

Calculate PFC from Volts
Calculate Voltage
Calculate PFC from Ze
Calculate Ze or Zs

PFC Impedance


To calculate impedance enter your Voltage and PFC values.


PFC Calculation Parameters:

  • Impedance measured in Ohms.
  • Voltage measured in Volts.
  • PFC measured in kA.


How to calculate impedance

Impedance = V ÷ I
Voltage (V) ÷ Current (I) = Impedance (Ohms)

Calculate PFC Three Phase


This PFC Fault Current Calculator automatically calculates PFC Single Phase and PFC Three Phase.


PFC Calculations:

  • Fault Current kA
  • Fault Current Amps
  • Voltage
  • Impedance
  • Single Phase Fault Current
  • Three Phase Fault Current

Enter ANY two values to calculate the remaining value.


When calculating PFC, the single phase kA and three phase kA results are displayed along with the equivalent value in Amps.

PFC Fault Current Calculator
PFC Results



What is PFC?

PFC (for the purpose of calculating fault current) is the acronym for Prospective Fault Current, not to be confused with PFC Power Factor Correction.


Prospective fault current is the amount of current that would flow in the event of a fault, fault current is measured in either kA (Kilo-amps) or Amps. 1kA = 1000 Amps, 0.5kA = 500 Amps, 0.05kA = 50 Amps.


There are different types of faults, Short Circuit and Earth Fault.

Prospective Short Circuit Fault Current is referred to to as PSCC while Prospective Earth Fault Current is referred to as PEFC.

What is fault current and short-circuit current?

Fault current is the amount of current that will flow under fault conditions.


Short-circuit current is the amount of current that will flow under a short circuit fault condition.


Short Circuit = A fault of negligible impedance between Live and Neutral (single phase or three phase), or Live and Live three phase. 

Why Calculate PFC?

Ideally fault current should be measured using the appropriate test equipment, however should you forget to measure the actual fault current it is possible to calculate the PFC from the measured voltage and measured earth fault loop impedance values from that particular part of the circuit. 

Why is Fault Current Important?

Knowing the PFC fault current value is important when selecting the appropriate electrical equipment such as over-current protection devices.


The over-current protection device (Fuses, MCB’s etc) have a maximum kA rating which they can withstand, therefore we need to know what the actual fault current will be at that point of the circuit to ensure the correct MCB, fuse or MCCB is selected.

Demo video may show an older version of the app

PFC Calculator

This PFC Fault Current Calculator is optimised to work on all screen sizes.


  • Easy to use
  • Preset data
  • Quick and instant results
  • Dedicated support team
Electrical Apps for iPhone
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