What is a common symptom of a faulty circuit breaker or relay?

• A. The circuit is intermittently powered or completely unpowered while fuses appear intact.
• B. The circuit remains permanently powered even when the switch is off.
• C. The fuses show obvious signs of melting.
• D. The circuit only powers non-critical loads.

Answer: (A)

A common symptom of a faulty circuit breaker or relay is intermittent power or complete loss of power to the circuit while the fuses or other protective devices remain intact. Breakers and relays are responsible for making or breaking the connection to the load. When their contacts wear, become corroded, or a relay coil/actuator sticks, the connection can open or close unpredictably. The result is power that comes and goes or drops out entirely, even though the protective fuses have not blown. This contrasts with a melted fuse, which points to a fuse-related overload, or other faults like a switch failing to break the circuit or a miswired condition, which are not the typical symptoms of a failing breaker or relay.