IEC EN 61557-8 Electrical Safety in Low Voltage Distribution Systems up to 1000 V AC and 1500 V DC, Part 8: Insulation Monitoring Devices for IT Systems

EUROLAB, with its state-of-the-art accredited laboratories and expert team, provides precise and fast testing services within the scope of IEC EN 61557-8 testing. IEC EN 61557-8 specifies requirements for insulation monitoring devices (IMD) that permanently monitor the grounding resistance RF of ungrounded ac IT systems, ac IT systems with galvanically connected dc circuits with rated voltages up to 1000 V ac.

IT systems are described in IEC 60364-4-41, among other literature. Additional data should be noted for the selection of devices of other standards. According to this part of IEC 61557, IMDs can also be used for de-energized TT, TN and IT systems or devices.

This edition constitutes a technical revision with the following important technical changes from the previous edition:

• Terms and definitions are complete;
• Abbreviations are listed and explained;
• Requirements revised;
• Mandatory and optional functions and their terminology adapted from IEC 61557-15;
• Added mechanical requirements;
• Added information about operating instructions;
• Type tests and routine tests have been completed;

IMDs shall consist of a visual warning device with local isolation warning (LIW) or shall be equipped with means for connecting such a device indicating operation with remote isolation warning (RIW). This device should not be provided with means to shut down.

Audible signaling devices, which can be connected either built-in or externally, can be equipped with a reset feature. In case of a newly occurring insulation fault, an insulation warning will be sent after a cleared insulation fault and after the devices are reset. The isolation warning will be local isolation warning (LIW) or remote isolation warning (RIW), or both.

EUROLAB assists manufacturers with IEC EN 61557-8 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.