Residual current operated circuit-breakers with integral overcurrent protection (RCBO) are miniature circuit-breakers with residual current trips for protecting systems in the event of a short-circuit and overload as per the requirements of VDE 0100 Part 430, and for protecting persons, farm animals and material items in the event of earth leakage currents as per VDE 0100 Part 410. Overload tripping occurs at currents in the overload range through a slow-blow, heat-sensitive bimetal trip and at short-circuit currents through an electromagnetic instantaneous trip. RCBOs with residual current characteristic A are independent of the mains voltage and allow the detection of sinusoidal AC currents and pulsating DC residual currents. RCBOs with tripping characteristic C are primarily suitable for power circuits with high switch-on or peak currents, as their short-circuit trip value is five to ten times the rated current. Standard devices are intended for monitoring circuits with a rated voltage of 230 V resp. 400 V and a rated frequency of 50 Hz, some series 60 Hz. FIB and FIC of this series are distinguished by a high rated switching capacity of 10 kA. They are available as 1+N variants.