Low-voltage switchgear and controlgear - Part 5-8: Control circuit devices and switching elements - Three-position enabling switches

IEC 60947-5-8:2020 RLV contains both the official IEC International Standard and its Redline version. The Redline version is not an official document, it is available in English only and provides you with a quick and easy way to compare all the changes between the official IEC Standard and its previous edition.

IEC 60947-5-8:2020 specifies requirements for three-position enabling switches. These switches are used as components of enabling devices to provide signals that,

- when activated, allow machine operation to be initiated by a separate start control, and

- when de-activated,

-- initiate a stop function, and

-- prevent initiation of machine operation.

This second edition cancels and replaces the first edition published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:

- due to the increasing range of useful applications of three-position enabling switches, note of scope, operational characteristics and tests are reviewed;

- figures for example of devices incorporating enabling switch are added in Annex A;

- new Annex B for procedure to determine reliability da