Electrical Inspection, Testing and Certification Practice Exam

Which test is used to check the breaking capacity of protective devices?

1. PFC or PSCC in KA

2. Continuity test

3. Insulation resistance test

4. Earth fault loop impedance test

The correct answer is: PFC or PSCC in KA

The test used to check the breaking capacity of protective devices is indeed the PFC (Prospective Fault Current) or PSCC (Prospective Short Circuit Current), measured in kiloamperes (KA). This test assesses the maximum current that a protective device, such as a circuit breaker or fuse, can handle before it operates to interrupt the circuit in the event of a fault. Understanding the breaking capacity is crucial because it determines whether the protective device can safely disconnect the power supply during a fault condition, thereby preventing damage to the electrical system and ensuring safety. The other tests mentioned serve different purposes. A continuity test checks if current can flow through a circuit, which does not provide information about the breaking capacity of protective devices. The insulation resistance test measures the integrity of insulation materials but is unrelated to fault currents or the performance of protective devices under short-circuit conditions. The earth fault loop impedance test is essential for assessing the effectiveness of earthing arrangements and system stability but does not evaluate the breaking capacity directly. Thus, the PFC or PSCC test is the only option that directly relates to assessing the capability of protective devices to handle fault conditions safely.