Full Calculation of Perspective Fault Current - PFC

[puffy]

I seem not to have access to the professional forums so I post this here:

I understand ohm's law and to get a current you use Volts/Resistance (V/R); so if it's Perspective Fault Current (PFC), it's V/R or Volts/Ze; and we divided by 1000 to convert to kA. Yes?

Is there a difference when calculating PFC on either earthing systems? For a TN-S, TN-C-S, TT or IT, is the same formula used?

Thanks.

 

[Brightspark9]

PFC calc is the same as far as I'm aware, earthing arrangements won't make a difference as in 99% of the time PSCC will be higher than PEFC.

 

[TJ Anderson]

Yes, it would be the same, but more specifically L-E is the Prospective Earth Fault Current (PEFC). L-N is the Prospective Short Circuit Current (PSSC). The higher reading of the two you then record as the Prospective Fault Current (PFC).