A protective device breaks an electrical circuit when a stated electric current that passes through it is exceeded. A protective device may include both the tripping unit and the breaking unit or it may simply represent the breaking unit if the tripping unit is specified individually as a protective device tripping unit.
An earth leakage circuit breaker is a protective device that opens, closes, or isolates a circuit and has short circuit protection but no overload protection. It attempts to break the circuit when there is a leakage of current from phase to earth, by measuring voltage on the earth conductor.