Circuit breaker is a device for closing and interrupting a circuit between separable contacts under both normal and abnormal conditions. It is arbitrarily grouped using many different criteria such as the intended voltage application, the location where they are installed, their external design characteristics, and, perhaps most importantly, by the method and the medium used for the interruption of current. It is required to control electrical power networks by switching circuits on, by carrying load and by switching circuits off under manual or automatic supervision. It is also designed to open a circuit automatically on a predetermined overload or ground-fault current without damage to itself or its associated equipment.