Abstract: A fault current circuit breaker has a summary current transformer whose secondary coil is connected to a voltage-independent energy storage circuit. A monostable or bistable transformer relay is actuated by an impulse by way of this energy storage circuit when a fault current flows to earth in the protected installation. When the relay contact is made, an electromagnetic lock trigger is actuated by the energizing current received from the mains supply, which triggers the switch lock of the FC switch. After this, the bistable transformer relay is returned to its initial position, either mechanically by way of an appropriate coupling with the switch lock, or electrically by way of a time delay or switch circuit, whereby the relay contact opens and the FC switch is again ready for switching on.

Abstract: A protective house-wiring switch with an overcurrent tripping device in a housing containing terminals for phase conductors and a neutral conductor, contacts for interrupting at least the phase conductors, at least one switch latch having at least one device connected to the respective phase conductors for actuating the contacts to interrupt the phase conductors, includes two overvoltage arresters for each phase conductor connected in cascade in direction of energy flow within the housing, one of the two overvoltage arresters being connected to the respective phase conductor ahead of the contact actuating device, and the other of the two overvoltage arresters being connected to the respective phase conductor after the contact actuating device.