what is prospective short circuit current?

Prospective Short Circuit Current refers to the maximum short circuit current which can flow in a circuit in the event of a fault such as a short circuit or an earth fault.  It is the maximum current which can flow in the system.  

All the components of the system such as the cables, bus bars and the measuring and protection systems should be rated with reference to the Prospective Short circuit current. The interrupting devices such as fuses and circuit breakers should have an interrupting capacity greater than the prospective short circuit current.   

Prospective Short Circuit Current depends on the resistances and reactances of the system.  The prospective Short Circuit Current can  be obtained by a Fault Level Calculation Study of the system.