Electrical safety in low voltage distribution systems up to 1000 V a.c. and 1500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 15: Functional safety requirements for insulation monitoring devices in IT systems and equipment for insulation fault location in IT systems (IEC 61557-15:2014); German version EN 61557-15:2014
交流1000V和直流1500V以下低压配电系统的电气安全保护措施的测试、测量或监测设备第15部分:IT系统中绝缘监测装置和IT系统中绝缘故障定位设备的功能安全要求