The insulation fault evaluator of the EDS460/490 series in combination with the ISOMETER® IRDH575 or the insulation fault test device PGH is designed to localize insulation faults in unearthed power supplies (IT systems). The test current signals generated by the insulation monitoring device IRDH575 or the insulation fault test device PGH are scanned by measuring current transformers and evaluated by the insulation fault evaluators. Up to 12 measuring current transformers can be connected to one EDS. A total of 90 EDS evaluators can be connected via one RS-485 interface (BMS protocol). Hence, up to 1080 circuits can be monitored. The maximum scanning time is approx. 4…10 s.