NE 142 is newly published

Abstract to NE 142 "Functional Safety of Electrotechnical Elements" (Version: 10.09.2012)

The most important electrical task with regard to functional safety is the safety related switch-off of a consumer.

This document provides the user with a code of practice to the implementation of functional safety with electrotechnical elements. It does not replace preliminary safety-relevant considerations such as finding answers to the question of whether safety requirements should be exclusively met with electrical means, or whether other preferable diverse solution approaches exist.

Appropriately designed electrotechnical elements can meet the requirements prescribed by the respective SIL classification on the basis of the layout and design instructions described within the document. The considerations presented here essentially focus on self-acting components in the event of a malfunction (e.g. contactors and circuit breakers). The intention in the examples illustrated in the document is, where possible, to employ standard electrotechnical components and circuits (e.g. standard typicals for Motor Control Center (MCC)) which individually satisfy SIL 1 to SIL 3 through adaptation of different safety requirements.

The use of proven safety principles and such elements with "prior use" have been mentioned here with some length.