Prospective short-circuit current

PSCC at a calculation point

Prospective short-circuit current is the fault current that could flow at a stated point if a short-circuit condition occurred. In Australian protection records it is usually carried as a kA value beside the switchboard, circuit, transformer or supply source being reviewed.

The point matters as much as the number. A value near a main switchboard may not describe a downstream distribution board, final circuit or equipment terminal. Use the term with 230/400 V a.c. source context, transformer/source data and protection worksheets so the value stays tied to the location that produced it.

Inputs that shape PSCC

Prospective current records need enough context to show where the estimate came from. A record may use measured data, DNSP or supply information, transformer impedance, source impedance, or a linked calculator result.

How it differs from breaking capacity

Prospective short-circuit current is not a device rating. It is the fault-current side of a comparison. Breaking capacity, cable withstand, protective-device data and switchboard ratings are separate records that may be checked against that current.

The term also does not decide protection coordination or cable suitability. It gives a calculated or supplied current value that later review can use with product data and project requirements.

Using PSCC in protection checks

Use the short-circuit current calculator when the source or transformer values are entered for a specific point. Use the fault-current relationship chart to understand the voltage and impedance relationship, then keep the result beside the board, circuit and review boundary it belongs to.