Which protective device is described as reliable and tamper-proof and can be used multiple times?

Which protective device is described as reliable and tamper-proof and can be used multiple times?

• A. Circuit breaker
• B. Fuse
• C. Relay
• D. Switch

Answer: (A)

Protective devices that automatically interrupt current when a fault occurs, while staying reliable and resistant to tampering and usable again after tripping, are circuit breakers. A circuit breaker detects an overcurrent and opens its contacts to stop the flow, then can be reset once the fault is cleared, making it suitable for repeated use without replacing the device. This combination of automatic protection, reset capability, and tamper resistance is why it fits the description best. Fuses provide protection by melting a conductor when overcurrent happens, which means they are single-use and must be replaced after a fault. A relay is a controlled switch activated by a signal and used to isolate or energize parts of a circuit, not primarily a protective device against faults. A switch is a manual disconnector and does not automatically protect the circuit from faults, though it can be operated multiple times.

Protective devices that automatically interrupt current when a fault occurs, while staying reliable and resistant to tampering and usable again after tripping, are circuit breakers. A circuit breaker detects an overcurrent and opens its contacts to stop the flow, then can be reset once the fault is cleared, making it suitable for repeated use without replacing the device. This combination of automatic protection, reset capability, and tamper resistance is why it fits the description best.

Fuses provide protection by melting a conductor when overcurrent happens, which means they are single-use and must be replaced after a fault. A relay is a controlled switch activated by a signal and used to isolate or energize parts of a circuit, not primarily a protective device against faults. A switch is a manual disconnector and does not automatically protect the circuit from faults, though it can be operated multiple times.