What is the function of a Circuit Breaker (CB) in an aircraft?

What is the function of a Circuit Breaker (CB) in an aircraft?

• A. Acts as an electrical fuse.
• B. Regulates cabin lighting.
• C. Controls fuel flow.
• D. Provides emergency oxygen.

Answer: (A)

Circuit breakers are protective devices in an aircraft electrical system. Their main job is to open the electrical path when there’s a fault, such as an overload or short circuit, to prevent wiring damage or fire. Unlike fuses, which must be replaced after they blow, circuit breakers can be reset once the fault is cleared, allowing the circuit to be restored. This protective, fault-clearing role is what makes this option the best description of a circuit breaker’s function. The other choices describe systems outside this protective function: cabin lighting regulation is a control task for the lighting circuit, fuel flow is managed by the fuel system, and emergency oxygen is part of a life-support system.

Circuit breakers are protective devices in an aircraft electrical system. Their main job is to open the electrical path when there’s a fault, such as an overload or short circuit, to prevent wiring damage or fire. Unlike fuses, which must be replaced after they blow, circuit breakers can be reset once the fault is cleared, allowing the circuit to be restored. This protective, fault-clearing role is what makes this option the best description of a circuit breaker’s function. The other choices describe systems outside this protective function: cabin lighting regulation is a control task for the lighting circuit, fuel flow is managed by the fuel system, and emergency oxygen is part of a life-support system.