IEC 61557-7:2007

Specifies requirements for measuring equipment applied to testing th e phase sequence in three-phase distribution systems. Indication of the phase sequence may be mechanical, visual and/or audible.

IEC 61557-7:2019 specifies the requirements applicable to measuring equipment for testing the phase sequence in three-phase distribution systems. Indication of the phase sequence can be mechanical, visual and/or audible. This document does not apply to additional measurements for other quantities. It does not apply to monitoring relays. IEC 61557-7:2019 cancels and replaces the second edition published in 2007. This edition constitutes a technical revision. This edition includes the following changes with respect to the previous edition: a) alignment of the structure with that of the whole IEC 61557 series; b) updated requirements in 4.3 in accordance with new editions of IEC 61010-1 and IEC 61010-031; c) the information on markings was extended; d) the information on the operating instructions was extended; e) complement to the information on the testing of leads; f) test leads for insulated conductors were introduced; g) Annex B was added with information on phase sequence tests and indications.