IEC 61557-4:2019 pdf download

IEC 61557-4:2019 pdf download.Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c.
1 Scope
This part of IEC 61 557 specifies the requirements applicable to equipment for measuring the resistance of earth conductors, protective earth conductors and conductors for equipotential bonding, including their connections and terminals, with an indication of the measured value or an indication of the limits.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 61 01 0-031 , Safety requirements for electrical equipment for measurement, control and laboratory use – Part 031: Safety requirements for hand-held and hand-manipulated probe assemblies for electrical test and measurement IEC 61 01 0-2-030:201 7, Safety requirements for electrical equipment for measurement, control, and laboratory use – Part 2-030: Particular requirements for equipment having testing or measuring circuits IEC 61 557-1 :201 9, Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC – Equipment for testing, measuring or monitoring of protective measures – Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61 557-1 apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp
4 Requirements
4.1 General In addition to the requirements of IEC 61 557-1 :201 9, Clause 4, the following requirements shall apply.Equipment intended for making measurements on distribution systems shall, at the minimum, be rated for measurement category III in accordance with IEC 61 01 0-2-030. Equipment intended for making measurements on electrical equipment shall, at the minimum, be rated for measurement category II in accordance with IEC 61 01 0-2-030. Test leads and test probes used with the measuring equipment shall fulfil the requirements of IEC 61 01 0-031 . 4.2 Measuring voltage The measuring voltage may be a DC or an AC voltage. The open-circuit voltage shall not exceed 24 V and shall not be less than 4 V. 4.3 Measuring current The measuring current within the minimum measuring range according to 4.5 shall not be less than 0,2 A. 4.4 Measuring with DC Resistance measuring equipment using a DC voltage as a measuring voltage shall be provided either with a reversing switch or allow the interchanging of test leads. 4.5 Measuring range The measuring range within which the operating uncertainty in accordance with 6.2 is maintained, shall include the values between 0,2 Ω and 2 Ω. The measuring range shall be marked on the equipment. With analogue only presentation of the measuring results, the range shall be marked on the scale. The measuring range to be marked in accordance with 4.5 on analogue measuring equipment shall cover at least 50 % of the length of the scale. The division on the scale within this range shall be at least 0,5 mm per 0,1 Ω. The resolution for digital equipment shall be at least 0,1 Ω. The operating uncertainty applies under the rated operating conditions given in IEC 61 557-1 :201 9, 4.3.4.6 External resistance When external resistances are included in the calibration as a zero offset, then this shall be indicated. This offset shall remain included in the calibration as long as it is indicated on the measuring instrument, regardless of any changes in range or function. 4.7 Indication of limits Equipment that purely indicates the result of a comparison between measurements and limit values shall unambiguously display if either the upper or lower limit is reached.4.8 Overvoltage The user shall not be exposed to danger and the equipment shall not be damaged when the measuring equipment is accidentally connected with 1 20 % of the nominal voltage of the distribution system on which the measuring equipment may be used. Protective devices of the test equipment may be activated.