safety device

A device designed to detect faults such as short circuits, leakage, or insulation breakdown in electrical and electronic equipment using sensors, and to shut down the affected part to protect people and property from electric shock or fire. A familiar example is a leakage breaker that detects leakage and cuts off the circuit. In electrical installations, to prevent cascading failures, multiple safety devices are combined and their detection and operation times are adjusted to stop only the minimum necessary faulty part — this mechanism is called protection coordination.