IEC 60947-5-8:2006

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 data for the switch used in functional safety applications is added.