ABSTRACT
This chapter deals with the determination of the prospective fault current (PFC) at the origin of an installation and at relevant points throughout. At the origin this may be ascertained by enquiry or measurement, whereas at other points measurement is the only option. The purpose of this test is to verify that the breaking capacity of a protective device is suitable for the PFC at the point that it is installed. A protective device with a breaking capacity of 3 kA installed in a distribution board where the PFC is 6 kA could result in serious damage and/or fire in the event of a fault. PFC is a generic term and can be either prospective short-circuit current (PSCC) or prospective earth fault current (PEFC). Both should be measured and the highest value is recorded. The testers are designed for single-phase use, so where a value of PSCC required for a three-phase system is determined.
