What issue can most commonly affect circuit breakers, leading to their failure?

Overheating is a common issue that can lead to the failure of circuit breakers. Circuit breakers are designed to interrupt electrical current flow when a fault occurs, but they also have specific temperature ratings. When excessive current flows through a circuit, it can generate heat beyond the breaker's safe operating temperature. This overheating can damage the internal components, degrade insulation, and ultimately lead to the failure of the breaker to trip when needed.

The design of circuit breakers includes thermal mechanisms that monitor temperature changes; if they get too hot, they may trip to protect the circuit. However, if a breaker is repeatedly exposed to high temperatures without tripping, it can lead to mechanical failure or malfunction. Thus, ensuring that circuit breakers operate within their specified limits is crucial for their reliable performance in any electrical system.