The
prospective short circuit current (PSCC) or
available fault current or
short circuit making current is the highest
electric current which can exist in a particular electrical system under
short-circuit conditions. It is determined by the
voltage and
impedance of the supply system. It is of the
order of a few thousand
amperes for a standard domestic
mains electrical installation, but may be as low as a few milliamperes in a
SELV (Safety Extra Low Voltage or, occasionally, Separated Extra Low Voltage) system or as high as hundreds of thousands of amps in large industrial power systems.