Abstract: A residual current device (1), having a residual current tripping circuit (4) which is independent of the mains voltage and contains a core balance transformer (2), and having overload protection (18) arranged in an overload tripping circuit (10) which is supplied with the mains current, wherein the residual current tripping circuit (4) and the overload tripping circuit (10) contain a common tripping relay (7) for operating a switching mechanism (8) which switches a conductor network (LN).

Abstract: Two detection systems are provided for a protective device, in particular an FI protective device, having a core balance transformer whose secondary winding is followed by a tripping relay for operating a switching mechanism, which switches a conductor network. In this case, a first detection system carries out the tripping function for fault currents at a fault current frequency below a changeover frequency. The second detection system carries out the tripping function for fault currents above the changeover frequency. The changeover frequency is in this case preferably not less than 1 kHz.

Abstract: A protective device against fault currents includes a triggering arrangement for performing at least the functions of detecting a fault current and/or triggering power-down of the network to be protected. The triggering arrangement, outside the most strict quartic curve (A), corresponds to the protection of persons in case of indirect contact, and below the triggering quartic curve (B), corresponds to protection against fire. The triggering quartic curve (B) satisfies the relationship: ILimit(f)/I&Dgr;n=F(f)=B=const., wherein ILimit(f)=WFire/UNetwork.

Abstract: A residual current device includes a residual current tripping circuit for actuating a release, and an additional monitoring device for checking the release, in which case a device is provided for electrically decoupling the residual current tripping circuit from the monitoring device.

Abstract: A socket-outlet, in which, only in response to preselected loads, voltage from the supply-side is connected through by a switching device to the load side. A voltage-supplied measuring device has a D.C. testing circuit and an A.C. testing circuit. Both testing circuits attempt to drive measuring currents across a connected load. The A.C. testing circuit operates at higher frequencies than the power-line frequency. An evaluation circuit is designed, on the basis of preselected criteria and on the basis of measuring values, in logical AND-connection, to determine whether switching contacts of the switching device should be closed.