Why does my circuit breaker buzz and then trip?

When a circuit breaker emits an audible buzzing or humming noise before finally tripping and cutting power, it is experiencing a combination of magnetic vibration and severe thermal-magnetic overload. The buzzing sound is typically generated by loose internal components, pitted contact points, or high electrical resistance vibrating under heavy current flow. As the excessive electrical load or short circuit continues to draw current beyond the breaker's rated amperage, internal bimetallic strips heat up rapidly until they bend past their mechanical threshold, forcing the breaker to trip and shut off power. You can troubleshoot electrical faults safely by shutting off power before inspection. You can verify that your corrective action is successful when redistributing heavy loads, repairing short circuits, and resetting the breaker ensures it remains quiet and stable under normal operating loads.