Which protective device is designed to interrupt current during overcurrent or short-circuit conditions?

Which protective device is designed to interrupt current during overcurrent or short-circuit conditions?

• A. Fuse.
• B. Overload timer.
• C. Relay.
• D. Circuit breaker.

Answer: (D)

Protecting a circuit by stopping current when faults occur is the idea being tested. A circuit breaker is designed to interrupt current automatically whenever overcurrent or a short circuit is detected. It does this by opening the circuit, which stops the flow of electricity to prevent damage or fire. Circuit breakers are resettable, so after the fault is cleared you can restore power without replacing any components. While a fuse also interrupts current, it does so by melting and is a one-time device that must be replaced after it blows. A relay by itself senses conditions and signals other equipment to trip, and an overload timer is a timing element used in protection schemes rather than the protective device that directly interrupts current.

Protecting a circuit by stopping current when faults occur is the idea being tested. A circuit breaker is designed to interrupt current automatically whenever overcurrent or a short circuit is detected. It does this by opening the circuit, which stops the flow of electricity to prevent damage or fire. Circuit breakers are resettable, so after the fault is cleared you can restore power without replacing any components.

While a fuse also interrupts current, it does so by melting and is a one-time device that must be replaced after it blows. A relay by itself senses conditions and signals other equipment to trip, and an overload timer is a timing element used in protection schemes rather than the protective device that directly interrupts current.