ABSTRACT
Load-break switch: A switch designed to interrupt load currents but not (greater) fault currents
Circuit breaker: A switch designed to interrupt fault currents
Automatic circuit reclosers: An overcurrent protective device that trips and recloses a preset number of times to clear transient faults or to isolate permanent faults
Automatic line sectionalizer: An overcurrent protective device used only with backup circuit breakers or reclosers but not alone
Fuse: An overcurrent protective device with a circuit-opening fusible member directly heated and destroyed by the passage of overcurrent through it in the event of an overload or short-circuit condition
Relay: A device that responds to variations in the conditions in one electric circuit to affect the operation of other devices in the same or in another electric circuit
Lightning arrester: A device put on electric power equipment to reduce the voltage of a surge applied to its terminals
The overcurrent protective devices applied to distribution systems include relay-controlled circuit breakers, automatic circuit reclosers, fuses, and automatic line sectionalizers.
