Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 8: Insulation monitoring devices for IT systems
This part of IEC 61557 specifies the requirements for insulation monitoring devices whichpermanently monitor the insulation resistance to earth of unearthed IT a.c. systems, for IT a.c.systems with galvanically connected d.c. circuits having nominal voltages up to 1 000 V a.c.,as well as of unearthed IT d.c. systems with voltages up to 1 500 V d.c. independent from themethod of measuring.NOTE 1 IT systems are described in IEC 60364-4-41 amongst other literature. Additional data for a selection of devices in other standards should be noted.NOTE 2 Various standards specify the use of insulation monitoring devices in IT systems. In such cases, the objective of