Safety device

In electrical and electronic equipment, when accidents such as short circuits, ground faults, or insulation breakdown occur, sensors detect the faulty section and stop the system to protect people and property from electric shock and fire. A familiar example is a ground fault circuit interrupter that detects a ground fault and shuts off the circuit. In electrical installations, to prevent cascading accidents, multiple protective devices are combined and their detection and operating times are coordinated so that only the minimum necessary faulty section is stopped; this mechanism is called protective coordination.