Electrical monitoring unit for detecting damage or failure of ground line between protective earthing and neutral-conductor and ground in TN-C system, has evaluating unit producing signal when measured current falls below threshold value

摘要

The unit (1) has a sensor line (9) switchable in parallel to a measuring section (20) of a ground line via two connection elements (10, 11). A current measuring device (13) i.e. inductive current sensor, measures current flowing through the sensor line. An evaluating unit (14) produces an output signal when the measured current falls below a threshold value. A high current carrying connector, which is connected with ends of sections (21, 22) of the ground line via the connection elements so that the sensor line and the connector are connected in parallel to each other.