IEC 61557-5:2019 specifies the requirements applicable to measuring equipment for measuring the resistance to earth using an AC voltage. IEC 61557-5:2019 cancels and replaces the second edition published in 2007. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) definitions and symbols in Clause 3 modified;
b) subclauses in Clause 4 restructured and aligned with other parts of the series;
c) limits for reduced voltages 25 V RMS or 35 V peak removed from 4.5;
d) requirements for clamps added;
e) marking for rated voltages to earth and measurement category added to Clause 5;
f) warning about absence of hazardous voltage added in Clause 5;
g) the term "percentage operating uncertainty" replaced by "operating uncertainty" in Clause 6;
h) equation for uncertainty corrected in Table 1;
i) new Annex A on test measurements with loop clamps added.