IEC 60981:2019

Extra heavy-duty electrical rigid steel conduits

IEC 60981:2019 specifies requirements for extra heavy-duty electrical rigid steel (EHDERS) conduits, couplings, nipples and elbows for electrical installations, including communications and fibre optics. This document also specifies threads for these components. It is not applicable to the conduits specified in IEC 60423. This third edition cancels and replaces the second edition published in 2004. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the second edition:
- addition of provisions for alternative coatings to zinc;
- addition of elasticity test for organic coatings;
- new Annex B on tests for evaluating alternative exterior coatings applied on extra heavy­duty electrical rigid steel (EHDERS) conduits.

Conduits électriques très lourds rigides en acier

General Information

• Status: Published
• Publication Date: 19-Aug-2019
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.120.10 - Conduits for electrical purposes
• Technical Committee: SC 23A - Cable management systems
• Drafting Committee: MT 1 - TC 23/SC 23A/MT 1
• Current Stage: PPUB - Publication issued
• Start Date: 20-Sep-2019
• Completion Date: 20-Aug-2019

Relations

• Revises: IEC 60981:2004 - Extra heavy-duty electrical rigid steel conduits
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60981 ®
Edition 3.0 2019-08
INTERNATIONAL
STANDARD
colour
inside
Extra heavy-duty electrical rigid steel conduits
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.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
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.
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Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
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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

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IEC 60981 ®
Edition 3.0 2019-08
INTERNATIONAL
STANDARD
colour
inside
Extra heavy-duty electrical rigid steel conduits

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.10 ISBN 978-2-8322-7310-4

– 2 – IEC 60981:2019 © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirements . 8
4.1 Tests . 8
4.2 Circular cross-section . 8
4.3 Wall thickness . 8
4.4 Surface condition . 8
4.4.1 General . 8
4.4.2 Localized surface imperfections . 8
4.5 Welding . 8
4.6 Cleaning . 8
4.7 Protective coating(s) . 8
4.7.1 Primary coating(s) . 8
4.7.2 Secondary coating(s) . 9
5 Dimensions. 9
5.1 Dimensions . 9
5.2 Threads . 9
5.2.1 General . 9
5.2.2 Pitch form . 9
5.2.3 Angle of thread . 9
6 Protective coatings . 9
6.1 Interior coatings . 9
6.1.1 Zinc . 9
6.1.2 Organic coatings. 9
6.2 Exterior coatings . 10
6.2.1 Zinc . 10
6.2.2 Alternative corrosion-resistant coating . 10
7 Threading and chamfering . 13
8 Couplings . 14
8.1 General . 14
8.1.1 Corrosion protection . 14
8.1.2 Chamfering . 14
8.1.3 Dimensions . 14
8.2 Coupling threads . 14
8.2.1 Thread form . 14
8.2.2 Dimensions . 14
9 Elbows and nipples . 14
10 Ductility . 14
10.1 Bending properties . 14
10.2 Ductility of zinc coating . 14
11 Marking . 15
11.1 General . 15
11.2 Required information . 15

Annex A (normative) Test for thickness of zinc coating on extra heavy-duty electrical
rigid steel (EHDERS) conduits . 24
A.1 Requirement . 24
A.2 Solutions required . 24
A.3 Preparation of samples . 24
A.4 Specimen surface condition . 24
A.5 Test method . 24
A.6 Results . 25
Annex B (normative) Tests for evaluating alternative exterior coatings applied on extra
heavy-duty electrical rigid steel (EHDERS) conduits . 26
B.1 Alternative corrosion-resistant coatings . 26
B.2 Preparation of specimens . 26
B.3 Air oven conditioning exposure . 28
B.4 Resistance to ultraviolet light and water exposure . 29
B.5 Resistance to salt spray (fog) exposure . 29
B.6 Resistance to moist carbon dioxide-sulfur dioxide-air exposure . 29
Bibliography . 30

Figure 1 – Dimensions of threads for EHDERS conduits . 18
Figure 2 – Basic form of taper thread . 19
Figure 3 – Limits on crest and root truncation of external and internal threads . 20
Figure 4 – Dimensions of a ferrous metal coupling . 21
Figure 5 – Dimensions of wedge . 22
Figure 6 – Essential dimensions for flame test . 23
Figure B.1 – Alternative corrosion program flowchart with sample requirements . 27
Figure B.2 – Scribe pattern . 28

Table 1 – Dimensions and mass of EHDERS conduits . 16
Table 2 – Dimensions of couplings . 17
Table 3 – Dimensions of 90° elbows . 17

– 4 – IEC 60981:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXTRA HEAVY-DUTY ELECTRICAL RIGID STEEL CONDUITS

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 atta
...

IEC 60981 ®
Edition 3.0 2019-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Extra heavy-duty electrical rigid steel conduits

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.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
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: [e-mail].
IEC 60981 ®
Edition 3.0 2019-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Extra heavy-duty electrical rigid steel conduits

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.10 ISBN 978-2-8322-7331-9

– 2 – IEC 60981:2019 RLV © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirements . 8
4.1 Tests . 8
4.2 Circular cross-section . 8
4.3 Wall thickness . 8
4.4 Surface condition . 8
4.4.1 General . 8
4.4.2 Localized surface imperfections . 8
4.5 Welding . 8
4.6 Cleaning . 8
4.7 Protective coating(s) . 8
4.7.1 Primary coating(s) . 8
4.7.2 Secondary coating(s) . 9
Alternative coatings .
5 Dimensions. 9
5.1 Dimensions . 9
5.2 Threads . 9
5.2.1 General . 9
5.2.2 Pitch form . 9
5.2.3 Angle of thread . 9
6 Protective coatings . 9
6.1 Interior coatings . 9
6.1.1 Zinc . 9
6.1.2 Organic coatings. 9
6.2 Exterior coatings . 10
6.2.1 Zinc coating . 10
6.2.2 Alternative corrosion-resistant coating . 11
7 Threading and chamfering . 14
8 Couplings . 14
8.1 General . 14
8.1.1 Corrosion protection . 14
8.1.2 Chamfering . 14
8.1.3 Dimensions . 14
8.2 Coupling threads . 14
8.2.1 Thread form . 14
8.2.2 Dimensions . 14
9 Elbows and nipples . 14
10 Ductility . 15
10.1 Bending properties . 15
10.2 Ductility of zinc coating . 15
11 Marking . 15
11.1 General . 15

11.2 Required information . 15
Annex A (normative) Test for thickness of zinc coating on extra heavy-duty electrical
rigid steel (EHDERS) conduits . 24
A.1 Requirement . 24
A.2 Solutions required . 24
A.3 Preparation of samples . 24
A.4 Specimen surface condition . 24
A.5 Test method . 24
A.6 Results . 25
Annex B (normative) Tests for evaluating alternative exterior coatings applied on extra
heavy-duty electrical rigid steel (EHDERS) conduits . 26
B.1 Alternative corrosion-resistant coatings . 26
B.2 Preparation of specimens . 26
B.3 Air oven conditioning exposure . 28
B.4 Resistance to ultraviolet light and water exposure . 29
B.5 Resistance to salt spray (fog) exposure . 29
B.6 Resistance to moist carbon dioxide-sulfur dioxide-air exposure . 29
Bibliography . 30

Figure 1 – Dimensions of threads for EHDERS conduits . 18
Figure 2 – Basic form of taper thread . 19
Figure 3 – Limits on crest and root truncation of external and internal threads . 20
Figure 4 – Dimensions of a ferrous metal coupling . 21
Figure 5 – Dimensions of wedge . 22
Figure 6 – Essential dimensions for flame test . 23
Figure B.1 – Alternative corrosion program flowchart with sample requirements . 27
Figure B.2 – Scribe pattern . 28

Table 1 – Dimensions and mass of EHDERS conduits . 16
Table 2 – Dimensions of couplings . 17
Table 3 – Dimensions of 90° elbows . 17

– 4 – IEC 60981:2019 RLV © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXTRA HEAVY-DUTY ELECTRICAL RIGID STEEL CONDUITS

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
...