Abstract: A circuit arrangement is described for monitoring an electronic tripping device for low-voltage switches having a microprocessor device which, in conjunction with a digital-analog converter, evaluates an overcurrent so that line power supply system. The microprocessor device (MPE) has a zero crossing comparator with which a constant test current pulse is transmittable, at zero crossings, to the electronic tripping device via an additional current transformer winding to measure the amplitude. In the case of deviations from the setpoint value, (re)calibration or actuation of the line tripping contacts, with an alarm signal being emitted, takes place.