IEC 61557-6:2019 is available as IEC 61557-6:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 61557-6:2019 specifies the requirements applicable to measuring equipment for testing the effectiveness of protective measures of residual current devices (RCD) installed in TT, TN and IT systems. It is not the purpose of this document to verify the RCD according to their product standards. IEC 61557-6:2019 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) addition of requirements for testing a new type of RCD; b) addition of requirements for type B RCDs (former Annex B); c) addition of new Annex B on recommended tripping times; d) alignment of the structure with that of the whole IEC 61557 series.