Overview

This part of the IEC 61557 series of standards defines special performance requirements for hand-held and hand manipulated current clamps and sensors for measurement of leakage currents in electrical distribution systems up to 1 000 V AC and 1 500 V DC taking into account the influence of high external low-frequency magnetic fields and other influencing quantities. This document specifies grades for current clamps and current sensors in relation to environments with high external magnetic fields and assists the user in selecting the appropriate measuring instrument for the specific application. Hand-held and hand manipulated current clamps and sensors may be designed as stand-alone measuring instruments or as accessories for other measuring instruments. This document does not apply to current clamps or sensors that are used in combination with devices for insulation fault location in accordance with IEC 61557-9, unless it is specified by the manufacturer. The standard differs from DIN EN 61557-13 (VDE 0413-13):2012-04 as follows: a) the term "fixing device" has been removed; b) the measuring range has been changed to a display range, the indication of DC or peak values has been added in 4.1; c) the frequency for the test of sensitivity for low-frequency magnetic fields has been defined in 4.2; d) the specified measuring range is now defined as the range of indicated values based on the operating uncertainty in 4.3; e) alignment of the structure with that of the whole IEC 61557 series; f) the variation E12 (maximum load current), may be specified according to the manufacturer's specification. When performing recurrent tests of electrical distribution systems it is becoming increasingly difficult to measure insulation resistance using measuring instruments according to IEC 61557-2 if the system cannot be shut down for extended periods and sensitive equipment is connected. Therefore, the measurement of leakage currents can provide additional information about whether a system is operating safely or unsafely. The user also has the option of positioning current clamps and current sensors at various measurement points in the system in order to troubleshoot false trips of residual current devices (RCDs), alarms triggered by residual current monitors (RCMs), and other issues caused by low-frequency leakage currents.

Document: references other documents

Responsible national committee

DKE/UK 964.1 - Messgeräte zum Prüfen und Überwachen von Schutzmaßnahmen