The A-ISOMETER® of the IR423 series is designed to monitor the insulation resistance RF of an unearthed AC system of 0…300 V to earth that is supplied by a mobile generator according to IEC 60364-5-551/DIN VDE 0100-551 (VDE 0100-551). The IR423 is suitable for AC systems with operating frequencies ≥ 30 Hz as well as for AC systems with directly connected DC circuits. The maximum permissible system leakage capacitance Cemax is 5 F.

The insulation monitoring device of the IR5002 series, continuously monitors the insulation resistance of unearthed DC systems to earth. The device is designed to signal a drop in insulation resistance below a minimum value.

The device combination A-ISOMETER® IRDH275BM-7 and the coupling device AGH675S-7 is designed to monitor the insulation resistance of unearthed medium voltage systems (IT systems). It is suitable for universal use in 3AC, combined AC/DC and DC systems. AC systems may include extensive DC-supplied loads.