IEC 62808:2015
(Main)Nuclear power plants - Instrumentation and control systems important to safety - Design and qualification of isolation devices
Nuclear power plants - Instrumentation and control systems important to safety - Design and qualification of isolation devices
IEC 62808:2015 establishes requirements for the design, analysis and qualification of isolation devices used to ensure electrical independence of redundant safety system circuits, or between safety and lower class circuits, as specified in IEC 60709. This standard includes guidance on the determination of the maximum credible fault that is applied to the isolation devices. The maximum credible fault can be used as a basis for the test levels used in testing based on other standards (e.g. IEC TS 61000-6-5 or IEC 62003).
Centrales nucléaires de puissance - Systèmes d'instrumentation et de contrôle-commande importants pour la sûreté - Conception et qualification des appareils d'isolement
L'IEC 62808:2015 établit des exigences pour la conception, les analyses et la qualification des appareils d'isolement utilisés pour garantir l'indépendance électriques entre les circuits des systèmes de sûreté redondants ou entre les circuits des systèmes de sûreté et des systèmes dont la classe de sûreté est inférieure, comme spécifié dans l'IEC 60709. La présente norme comprend des recommandations portant sur la détermination du défaut maximal prévisible qui est pris en compte pour les appareils d'isolement. Le défaut maximal prévisible peut être utilisé comme une base pour le niveau des essais définis à partir d'autres normes (par exemple l'IEC TS 61000-6-5 ou l'IEC 62003).
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IEC 62808 ®
Edition 1.1 2018-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Nuclear power plants – Instrumentation and control systems important
to safety – Design and qualification of isolation devices
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
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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 corrigendum or an amendment might have been published.
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IEC 62808 ®
Edition 1.1 2018-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
colour
inside
Nuclear power plants – Instrumentation and control systems important
to safety – Design and qualification of isolation devices
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.120.20 ISBN 978-2-8322-5738-8
IEC 62808 ®
Edition 1.1 2018-05
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Nuclear power plants – Instrumentation and control systems important
to safety – Design and qualification of isolation devices
– 2 – IEC 62808:2015+AMD1:2018 CSV
© IEC 2018
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols and abbreviations . 8
5 General principles for isolation devices . 8
5.1 General . 8
5.2 Isolation characteristics . 9
5.3 Actuation priority . 10
6 Isolation device design requirements . 10
6.1 Requirements on isolation device application . 10
6.1.1 Isolation device power . 10
6.1.2 Maximum credible fault . 10
6.1.3 Energy limiting devices . 11
6.2 Requirements on isolation device design . 11
6.2.1 Basic design requirements . 11
6.2.2 Postulated faults . 12
6.2.3 Physical component arrangement . 12
6.3 Power isolation devices . 13
6.3.1 General . 13
6.3.2 Circuit breaker tripped by fault currents . 13
6.3.3 Circuit breaker tripped by fault signals . 13
6.3.4 Input current limiters . 13
6.3.5 Fuses . 13
7 Qualification test requirements . 14
7.1 General . 14
7.2 Requirements on the test method . 14
7.2.1 Test specification . 14
7.2.2 Testing energy limiting devices . 14
7.2.3 Qualification test environment . 14
7.3 Application specific testing . 15
7.3.1 General . 15
7.3.2 Isolation of safety circuits from lower class circuits . 15
7.3.3 Isolation between redundant safety circuits . 15
7.4 Documentation of test requirements and results . 16
Bibliography . 17
Figure 1 – Application of maximum credible fault . 11
Figure 2 – Application of postulated fault . 12
© IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS IMPORTANT TO SAFETY –
DESIGN AND QUALIFICATION OF ISOLATION DEVICES
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 62808 edition 1.1 contains the first edition (2015-05) [documents 45A/1004/FDIS and
45A/1019/RVD] and its amendment 1 (2018-05) [documents 45A/1192/FDIS and 45A/1204/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text.
A separate Final version with all changes accepted is available in this publication.
– 4 – IEC 62808:2015+AMD1:2018 CSV
© IEC 2018
International Standard IEC 62808 has been prepared by subcommittee 45A: Instrumentation,
control and electrical systems of nuclear facilities, of IEC technical committee 45: Nuclear
instrumentation.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability 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.
A bilingual version of this publication may be issued at a later date.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
© IEC 2018
INTRODUCTION
a) Technical background, main issues and organisation of the standard
I&C (instrumentation and control) systems important to safety in nuclear power plants need to
tolerate the effects of plant / equipment faults as well as internal and external hazards.
IEC 60709 provides requirements to establish independence between redundant portions of
safety systems, and between safety systems and systems of a lower class. Among the
techniques available to increase the level of tolerability of I&C systems to such effects is the
provision of isolation devices where connections are made between redundant divisions of
safety equipment, or between safety equipment and systems of a lower class. This standard
provides technical requirements and recommendations for the design and qualification of
isolation devices that are required by IEC 60709. This standard deals with the criteria and
methods used to confirm that the design of isolation devices ensures that credible failures in
the connected lower class system or redundant channels will not prevent the safety systems
from meeting their required functions. Isolation devices may be r
...
IEC 62808 ®
Edition 1.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation and control systems important to
safety – Design and qualification of isolation devices
Centrales nucléaires de puissance – Systèmes d’instrumentation et de
contrôle-commande importants pour la sûreté – Conception et qualification
des appareils d’isolement
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
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et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
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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
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variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
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77, 86 and CISPR.
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IEC 62808 ®
Edition 1.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Instrumentation and control systems important to
safety – Design and qualification of isolation devices
Centrales nucléaires de puissance – Systèmes d’instrumentation et de
contrôle-commande importants pour la sûreté – Conception et qualification
des appareils d’isolement
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20 ISBN 978-2-8322-2665-0
– 2 – IEC 62808:2015 © IEC 2015
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols and abbreviations . 8
5 General principles for isolation devices . 8
5.1 General . 8
5.2 Isolation characteristics . 9
5.3 Actuation priority . 10
6 Isolation device design requirements . 10
6.1 Requirements on isolation device application . 10
6.1.1 Isolation device power . 10
6.1.2 Maximum credible fault . 10
6.1.3 Energy limiting devices . 11
6.2 Requirements on isolation device design . 11
6.2.1 Basic design requirements . 11
6.2.2 Postulated faults . 12
6.2.3 Physical component arrangement . 12
6.3 Power isolation devices . 13
6.3.1 General . 13
6.3.2 Circuit breaker tripped by fault currents . 13
6.3.3 Circuit breaker tripped by fault signals . 13
6.3.4 Input current limiters . 13
6.3.5 Fuses . 13
7 Qualification test requirements . 13
7.1 General . 13
7.2 Requirements on the test method . 14
7.2.1 Test specification . 14
7.2.2 Testing energy limiting devices . 14
7.2.3 Qualification test environment . 14
7.3 Application specific testing . 15
7.3.1 General . 15
7.3.2 Isolation of safety circuits from lower class circuits . 15
7.3.3 Isolation between redundant safety circuits . 15
7.4 Documentation of test requirements and results . 15
Bibliography . 16
Figure 1 – Application of maximum credible fault . 11
Figure 2 – Application of postulated fault . 12
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS IMPORTANT TO SAFETY –
DESIGN AND QUALIFICATION OF ISOLATION DEVICES
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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 appl
...
IEC 62808 ®
Edition 1.1 2018-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Nuclear power plants – Instrumentation and control systems important
to safety – Design and qualification of isolation devices
Centrales nucléaires de puissance – Systèmes d'instrumentation et de
contrôle-commande importants pour la sûreté – Conception et qualification
des appareils d'isolement
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 l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.
IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
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 corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) 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 IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.
Recherche de publications IEC - Electropedia - www.electropedia.org
webstore.iec.ch/advsearchform Le premier dictionnaire d'électrotechnologie en ligne au
La recherche avancée permet de trouver des publications IEC monde, avec plus de 22 000 articles terminologiques en
en utilisant différents critères (numéro de référence, texte, anglais et en français, ainsi que les termes équivalents dans
comité d’études,…). Elle donne aussi des informations sur les 16 langues additionnelles. Egalement appelé Vocabulaire
projets et les publications remplacées ou retirées. Electrotechnique International (IEV) en ligne.
IEC Just Published - webstore.iec.ch/justpublished Glossaire IEC - std.iec.ch/glossary
Restez informé sur les nouvelles publications IEC. Just 67 000 entrées terminologiques électrotechniques, en anglais
Published détaille les nouvelles publications parues. et en français, extraites des articles Termes et Définitions des
Disponible en ligne et une fois par mois par email. publications IEC parues depuis 2002. Plus certaines entrées
antérieures extraites des publications des CE 37, 77, 86 et
Service Clients - webstore.iec.ch/csc CISPR de l'IEC.
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
IEC 62808 ®
Edition 1.1 2018-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Nuclear power plants – Instrumentation and control systems important
to safety – Design and qualification of isolation devices
Centrales nucléaires de puissance – Systèmes d'instrumentation et de
contrôle-commande importants pour la sûreté – Conception et qualification
des appareils d'isolement
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.120.20 ISBN 978-2-8322-5738-8
IEC 62808 ®
Edition 1.1 2018-05
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Nuclear power plants – Instrumentation and control systems important
to safety – Design and qualification of isolation devices
Centrales nucléaires de puissance – Systèmes d'instrumentation et de
contrôle-commande importants pour la sûreté – Conception et qualification
des appareils d'isolement
– 2 – IEC 62808:2015+AMD1:2018 CSV
© IEC 2018
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols and abbreviations . 8
5 General principles for isolation devices . 8
5.1 General . 8
5.2 Isolation characteristics . 9
5.3 Actuation priority . 10
6 Isolation device design requirements . 10
6.1 Requirements on isolation device application . 10
6.1.1 Isolation device power . 10
6.1.2 Maximum credible fault . 10
6.1.3 Energy limiting devices . 11
6.2 Requirements on isolation device design . 11
6.2.1 Basic design requirements . 11
6.2.2 Postulated faults . 12
6.2.3 Physical component arrangement . 12
6.3 Power isolation devices . 13
6.3.1 General . 13
6.3.2 Circuit breaker tripped by fault currents . 13
6.3.3 Circuit breaker tripped by fault signals . 13
6.3.4 Input current limiters . 13
6.3.5 Fuses . 13
7 Qualification test requirements . 14
7.1 General . 14
7.2 Requirements on the test method . 14
7.2.1 Test specification . 14
7.2.2 Testing energy limiting devices . 14
7.2.3 Qualification test environment . 14
7.3 Application specific testing . 15
7.3.1 General . 15
7.3.2 Isolation of safety circuits from lower class circuits . 15
7.3.3 Isolation between redundant safety circuits . 15
7.4 Documentation of test requirements and results . 16
Bibliography . 17
Figure 1 – Application of maximum credible fault . 11
Figure 2 – Application of postulated fault . 12
© IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS –
INSTRUMENTATION AND CONTROL SYSTEMS IMPORTANT TO SAFETY –
DESIGN AND QUALIFICATION OF ISOLATION DEVICES
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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 appli
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