HOLT Electricians Practice Exam

What type of protection do motor feeder conductors require against short-circuits and ground faults?

1. Complete insulation

2. Current limiting fuses

3. Circuit breakers

4. Non-fused disconnects

The correct answer is: Circuit breakers

Motor feeder conductors need reliable protection against short-circuits and ground faults to ensure safety and minimize potential damage. Circuit breakers serve this purpose effectively as they can detect overcurrent situations and interrupt the circuit to prevent hazards. They are designed to trip automatically in the event of a fault, thus preventing equipment damage and ensuring the safety of the electrical system. In contrast, while complete insulation is important for preventing electrical leakage and ensuring safety, it does not provide active protection against short-circuits and ground faults. Current limiting fuses can help in some applications by reducing the let-through energy during a fault but may not provide the same level of protection and convenience as circuit breakers, which can be reset after tripping. Non-fused disconnects do not provide overcurrent protection and are typically used for isolation purposes rather than fault protection. Therefore, circuit breakers are critical in providing the necessary protection for motor feeder conductors.