IEC 61386-21:2021

IEC 61386-21 ®
Edition 2.0 2021-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Conduit systems for cable management –
Part 21: Particular requirements – Rigid conduit systems

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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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
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latest edition, a corrigendum or an amendment might have been published.

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IEC 61386-21 ®
Edition 2.0 2021-04
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Conduit systems for cable management –

Part 21: Particular requirements – Rigid conduit systems

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.10 ISBN 978-2-8322-9704-9

– 2 – IEC 61386-21:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirements . 6
5 General conditions for tests . 6
6 Classification . 6
7 Marking and documentation . 7
8 Dimensions. 7
9 Construction . 9
10 Mechanical properties. 9
11 Electrical properties . 11
12 Thermal properties . 11
13 Fire hazard . 12
14 External influences . 12
15 Electromagnetic compatibility . 12
Annex A (normative) Classification coding for conduit systems . 18
Annex B (normative) Determination of material thickness . 18
Annex C (normative) Additional test requirements for conduit systems already
complying with IEC 61386-1:2008 . 18
Annex AA (informative) Calculation for minimum and maximum rate of increase of
force for 10.2.4 . 19

Figure 101 – Bending apparatus for metallic and composite conduits . 13
Figure 102 – Gauge for checking the minimum inside diameter of the conduit system
after impact, bending, collapse and resistance to heat tests . 14
Figure 103 – Bending apparatus for non-metallic and composite conduit . 15
Figure 104 – Arrangement for collapse test . 16
Figure AA.1 – Graph showing force against time for 750 N force. 19

Table 101 – Thread lengths . 8
Table 102 – Maximum entry diameter and minimum entry length details . 8
Table AA.1 – Minimum and maximum rate of increase of force for 10.2.4 . 20

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONDUIT SYSTEMS FOR CABLE MANAGEMENT –

Part 21: Particular requirements – Rigid conduit systems

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 redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 61386-21:2002. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

– 4 – IEC 61386-21:2021 RLV © IEC 2021
International Standard IEC 61386-21 has been prepared by subcommittee 23A: Cable
management systems, of IEC technical committee 23: Electrical accessories:
This second edition cancels and replaces the first edition published in 2002. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Subclause 7.1.103 has been added requiring the manufacturer to declare whether the
conduit is bendable;
b) Annex AA has been added to provide guidance on the application of a constantly
increasing force.
The text of this International Standard is based on the following documents:
FDIS Report on voting
23A/950/FDIS 23A/955/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 61386 series, published under the general title Conduit
systems for cable management, can be found on the IEC website.
This document is to be used in conjunction with IEC 61386-1:2008 and
IEC 61386-1:2008/AMD1:2017.
This document supplements or modifies the corresponding clauses of IEC 61386-1:2008 and
IEC 61386-1:2008/AMD1:2017. Where a particular clause or subclause of IEC 61386-1:2008
and IEC 61386-1:2008/AMD1:2017 is not mentioned in this document, that clause or
subclause applies as far as is reasonable. Where this document states "addition",
"modification" or "replacement", the relevant text of IEC 61386-1:2008 and
IEC 61386-1:2008/AMD1:2017 is to be adapted accordingly.
Subclauses, tables and figures which are in addition to those in IEC 61386-1:2008 and
IEC 61386-1:2008/AMD1:2017 are numbered starting with 101. Annexes which are additional
to those in IEC 61386-1:2008 and IEC 61386-1:2008/AMD1:2017 are lettered AA, BB, etc.
In this document, the following print types are used:
– Requirements proper: in roman type.
– Test specifications: in italic type.
– Explanatory matter: in smaller roman type.

The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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.

– 6 – IEC 61386-21:2021 RLV © IEC 2021
CONDUIT SYSTEMS FOR CABLE MANAGEMENT –

Part 21: Particular requirements – Rigid conduit systems

1 Scope
This clause of part 1 is applicable, except as follows:
Clause 1 of IEC 61386-1:2008 is applicable, except as follows:
Addition:
This part of IEC 61386 specifies the requirements for rigid conduit systems.
2 Normative references
This clause of part 1 is applicable.
Clause 2 of IEC 61386-1:2008 and of IEC 61386-1:2008/AMD1:2017 are applicable, except as
follows:
Addition:
IEC 61386-1:2008, Conduit systems for cable management – Part 1: General requirements
IEC 61386-1:2008/AMD1:2017
3 Terms and definitions
This clause of part 1 is applicable.
Clause 3 of IEC 61386-1:2008 and of IEC 61386-1:2008/AMD1:2017 are applicable.
4 General requirements
This clause of part 1 is applicable.
Clause 4 of IEC 61386-1:2008 is applicable.
5 General conditions for tests
This clause of part 1 is applicable.
Clause 5 of IEC 61386-1:2008 and of IEC 61386-1:2008/AMD1:2017 are applicable.
6 Classification
This clause of part 1 is applicable, exce
...

IEC 61386-21 ®
Edition 2.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Conduit systems for cable management –
Part 21: Particular requirements – Rigid conduit systems

Systèmes de conduits pour la gestion du câblage –
Partie 21: Exigences particulières – Systèmes de conduits rigides

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.

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utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
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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 IEC online collection - oc.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 000 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 18 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
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If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
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IEC 61386-21 ®
Edition 2.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Conduit systems for cable management –

Part 21: Particular requirements – Rigid conduit systems

Systèmes de conduits pour la gestion du câblage –

Partie 21: Exigences particulières – Systèmes de conduits rigides

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.10 ISBN 978-2-8322-1053-1

– 2 – IEC 61386-21:2021 © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General requirements . 5
5 General conditions for tests . 5
6 Classification . 5
7 Marking and documentation . 5
8 Dimensions. 6
9 Construction . 7
10 Mechanical properties. 7
11 Electrical properties . 9
12 Thermal properties . 9
13 Fire hazard . 9
14 External influences . 9
15 Electromagnetic compatibility . 10
Annex A (normative) Classification coding for conduit systems . 14
Annex B (normative) Determination of material thickness . 14
Annex C (normative) Additional test requirements for conduit systems already
complying with IEC 61386-1:2008 . 14
Annex AA (informative) Calculation for minimum and maximum rate of increase of
force for 10.2.4 . 15

Figure 101 – Bending apparatus for metallic and composite conduits . 10
Figure 102 – Gauge for checking the minimum inside diameter of the conduit system
after impact, bending, collapse and resistance to heat tests . 11
Figure 103 – Bending apparatus for non-metallic and composite conduit . 12
Figure 104 – Arrangement for collapse test . 13
Figure AA.1 – Graph showing force against time for 750 N force. 15

Table 101 – Thread lengths . 6
Table 102 – Maximum entry diameter and minimum entry length details . 7
Table AA.1 – Minimum and maximum rate of increase of force for 10.2.4 . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONDUIT SYSTEMS FOR CABLE MANAGEMENT –

Part 21: Particular requirements – Rigid conduit systems

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.
International Standard IEC 61386-21 has been prepared by subcommittee 23A: Cable
management systems, of IEC technical committee 23: Electrical accessories:
This second edition cancels and replaces the first edition published in 2002. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Subclause 7.1.103 has been added requiring the manufacturer to declare whether the
conduit is bendable;
b) Annex AA has been added to provide guidance on the application of a constantly
increasing force.
– 4 – IEC 61386-21:2021 © IEC 2021
The text of this International Standard is based on the following documents:
FDIS Report on voting
23A/950/FDIS 23A/955/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 61386 series, published under the general title Conduit
systems for cable management, can be found on the IEC website.
This document is to be used in conjunction with IEC 61386-1:2008 and
IEC 61386-1:2008/AMD1:2017.
This document supplements or modifies the corresponding clauses of IEC 61386-1:2008 and
IEC 61386-1:2008/AMD1:2017. Where a particular clause or subclause of IEC 61386-1:2008
and IEC 61386-1:2008/AMD1:2017 is not mentioned in this document, that clause or
subclause applies as far as is reasonable. Where this document states "addition",
"m
...