IEC 60947-5-8:2020

IEC 60947-5-8 ®
Edition 2.0 2020-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 5-8: Control circuit devices and switching elements – Three-position
enabling switches
Appareillage à basse tension –
Partie 5-8: Appareils et éléments de commutation pour circuits de commande –
Interrupteurs de commande de validation à trois positions

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IEC 60947-5-8 ®
Edition 2.0 2020-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –

Part 5-8: Control circuit devices and switching elements – Three-position

enabling switches
Appareillage à basse tension –

Partie 5-8: Appareils et éléments de commutation pour circuits de commande –

Interrupteurs de commande de validation à trois positions

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-8606-7

– 2 – IEC 60947-5-8:2020 © IEC 2020
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Classification . 7
5 Characteristics . 7
6 Product information . 8
7 Normal service, mounting and transport conditions . 9
8 Constructional and performance requirements . 10
9 Tests . 14
Annex A (informative) Example of enabling devices incorporating a three-position
enabling switch . 21
Annex B (normative) Procedure to determine reliability data for three-position enabling
switches used in functional safety applications . 24
Bibliography . 25

Figure 1 – Operation of three-position enabling switches . 12
Figure 2 – Operating force, travel and enabling contact status . 13
Figure A.1 – Grip type enabling device . 21
Figure A.2 – One hand teaching pendant type enabling device . 21
Figure A.3 – Two hand teaching pendant type enabling device . 22
Figure A.4 – Manual pulse generator . 22
Figure A.5 – Grip type enabling device for hand-held machine . 22
Figure A.6 – Foot actuated enabling device . 23
Figure A.7 – Hoist controller . 23
Figure A.8 – Joystick type enabling device . 23

Table 1 – Force values for F . 13
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 5-8: Control circuit devices and switching elements –
Three-position enabling switches

FOREWORD
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International Standard IEC 60947-5-8 has been prepared by subcommittee 121A: Low-voltage
switchgear and controlgear, of IEC technical committee 121: Switchgear and controlgear and
their assemblies for low voltage.
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:
a) due to the increasing range of useful applications of three-position enabling switches, note
of scope, operational characteristics and tests are reviewed;
b) figures for example of devices incorporating enabling switch are added in Annex A;
c) new Annex B for procedure to determine reliability data for the switch used in functional
safety applications is added.
– 4 – IEC 60947-5-8:2020 © IEC 2020
The text of this document is based on the following documents:
FDIS Report on voting
121A/358/FDIS 121A/369/RVD
Full information on the voting for the approval of this document can be found in the report on
voting indicated in the above table.
This document should be used in conjunction with IEC 60947-1:2020 and
IEC 60947-5-1:2016.
The provisions of the general rules, IEC 60947-1, are applicable to this standard, where
specifically called for. General rules clauses and subclauses thus applicable, as well as tables,
figures and annexes are identified by a reference to IEC 60947-1, for example 1.2.3 or
Annex A of IEC 60947-1:2020.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60947 series, under the general title Low-voltage switchgear and
controlgear, can be found on the IEC website.
The committee has decided that the co
...