IEC TR 61641:2008

Enclosed low-voltage switchgear and controlgear assemblies - Guide for testing under conditions of arcing due to internal fault

This technical report applies to enclosed low-voltage switchgear and controlgear assemblies hereafter called ASSEMBLIES manufactured according to IEC 60439-1. This second edition cancels and replaces the first edition (1996) and constitutes a technical revision. The main change introduced in this new edition is the following: the concept of ASSEMBLY protection under arcing conditions has been introduced.

Ensembles d'appareillage à basse tension sous enveloppe - Guide pour l'essai en conditions d'arc dues à un défaut interne

Le présent rapport technique s'applique aux ensembles d'appareillage à basse tension sous enveloppe - désignés ci-après ENSEMBLES- fabriqués selon la CEI 60439-1. Cette seconde édition annule et remplace la première édition (1996) et constitue une révision technique. La principale modification introduite dans cette nouvelle édition est la suivante: -la notion de protection d'ENSEMBLE en conditions d'arc a été introduite.

General Information

• Status: Published
• Publication Date: 29-Jan-2008
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: SC 121B - Low-voltage switchgear and controlgear assemblies
• Drafting Committee: MT 2 - TC 121/SC 121B/MT 2
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 09-Sep-2014

Relations

• Revised: IEC TR 61641:2014 - Enclosed low-voltage switchgear and controlgear assemblies - Guide for testing under conditions of arcing due to internal fault
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC/TR 61641
Edition 2.0 2008-01
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Enclosed low-voltage switchgear and controlgear assemblies – Guide for testing
under conditions of arcing due to internal fault

Ensembles d'appareillage à basse tension sous enveloppe – Guide pour l'essai
en conditions d'arc dues à un défaut interne

IEC/TR 61641:2008
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des
normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC/TR 61641
Edition 2.0 2008-01
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Enclosed low-voltage switchgear and controlgear assemblies – Guide for
testing under conditions of arcing due to internal fault

Ensembles d'appareillage à basse tension sous enveloppe – Guide pour l'essai
en conditions d'arc dues à un défaut interne
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
M
CODE PRIX
ICS 29.130.20 ISBN 2-8318-9540-5

– 2 – TR 61641 © IEC:2008
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Classification of low-voltage switchgear and controlgear assemblies .7
5 Assembly characteristics under arcing conditions .8
6 Testing .8
6.1 General .8
6.2 Voltage.8
6.3 Current.8
6.4 Frequency .9
6.5 Duration of the test.9
7 Test procedure .9
7.1 Supply circuit .9
7.2 Arc initiation .9
7.3 Repetition of the test .11
7.4 Indicators (for observing the thermal effects of gases).11
7.4.1 General .11
7.4.2 Fitting of the indicators .11
8 Assessment of the test .11
9 Test report.12

Figure 1 – Mounting frame for indicators.13

Table 1 – Sizes of the copper ignition wire without current limiting protection device .10
Table 2 – Sizes of the copper ignition wire with current limiting protection device .10

TR 61641 © IEC:2008 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENCLOSED LOW-VOLTAGE SWITCHGEAR
AND CONTROLGEAR ASSEMBLIES –
GUIDE FOR TESTING UNDER CONDITIONS
OF ARCING DUE TO INTERNAL FAULT

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 61641, which is a technical report, has been prepared by subcommittee 17D: Low-voltage
switchgear and controlgear assemblies, of IEC technical committee 17: Switchgear and
controlgear. This second edition cancels and replaces the first edition (1996) and constitutes
a technical revision.
The main changes introduced in this new edition are the following:
– the numbering of the clauses has been changed in order to meet the requirements in
Part 2 of the ISO/IEC Directives;
– the concept of ASSEMBLY protection under arcing conditions has been introduced;

– 4 – TR 61641 © IEC:2008
– existing terms and definitions have been modified and new terms and definitions have
been added (3.4 to 3.9);
– Clause 4 (Classification of low-voltage switchgear and controlgear assemblies) and
Clause 5 (ASSEMBLY characteristics under arcing conditions) have been added;
– Clause 4 “Test procedure” in the former edition has been split into the new Clauses 6
“Testing” and 7 “Test procedure” with actualised requirements;
– new Table 2 with sizes of the copper ignition wire with current limiting protection device
has been added;
– the new criteria 6 and 7 for ASSEMBLY protection have been added in Clause 8.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
17D/352/DTR 17D /353/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The French version of this technical report has not been voted upon.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
TR 61641 © IEC:2008 – 5 –
INTRODUCTION
The occurrence of arcs inside enclosed low-voltage switchgear and controlgear assemblies -
hereafter called ASSEMBLIES - is coupled with various physical phenomena. For example,
the arc energy resulting from an arc developed in air at atmospheric pressure within the
enclosure will cause an internal overpressure and local overheating which will result in
mechanical and thermal stressing of the ASSEMBLY. Moreover, the materials involved may
produce hot decomposition products, either gases or vapours, which may be discharged to
the outside
...