IEC 63026:2019

IEC 63026 ®
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
colour
inside
Submarine power cables with extruded insulation and their accessories for
rated voltages from 6 kV (U = 7,2 kV) up to 60 kV (U = 72,5 kV) –
m m
Test methods and requirements
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.: +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and withdrawn publications.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.
IEC 63026 ®
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
colour
inside
Submarine power cables with extruded insulation and their accessories for

rated voltages from 6 kV (U = 7,2 kV) up to 60 kV (U = 72,5 kV) –
m m
Test methods and requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.060.20 ISBN 978-2-8322-7642-6

– 2 – IEC 63026:2019 © IEC 2019
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
3.1 Definitions of dimensional values (thicknesses, cross-sections, etc.) . 12
3.2 Definitions concerning tests . 12
3.3 Other definitions . 12
3.4 Definitions concerning test objects . 13
4 Voltage designations, materials and rounding of numbers . 14
4.1 Rated voltages . 14
4.2 Cable insulating compounds . 15
4.3 Rounding of numbers . 15
5 Cable construction . 16
5.1 General . 16
5.2 Conductors . 16
5.3 Insulation . 16
5.4 Screening . 16
5.5 Metal screen . 17
5.6 Core oversheathing materials . 17
5.7 Assembly of three-core cables and fillers . 17
5.8 Cable armour . 17
5.9 Cable outer serving . 18
5.10 Packaging . 18
6 Cable characteristics . 18
7 Accessory characteristics . 19
8 Test conditions . 19
8.1 Ambient temperature. 19
8.2 Frequency and waveform for AC voltage tests . 19
8.3 Lightning impulse test . 19
8.4 Relationship of test voltages to rated voltages . 19
8.5 Determination of the cable conductor temperature . 20
9 Routine tests on cables and accessories . 20
9.1 General . 20
9.2 Test on manufacturing lengths . 20
9.2.1 Partial discharge test . 20
9.2.2 AC voltage test . 20
9.3 Test on factory joints. 21
9.4 Test on delivery lengths . 21
9.4.1 General . 21
9.4.2 AC voltage test . 21
9.4.3 Partial discharge test . 21
9.5 Test on accessories . 21
10 Sample tests on cables . 21
10.1 General . 21
10.2 Frequency of tests . 22

10.3 Repetition of tests . 22
10.4 Conductor examination . 22
10.5 Measurement of electrical resistance of conductor and of metal screen . 22
10.6 Measurement of thickness of insulation . 23
10.6.1 General . 23
10.6.2 Requirements for the insulation . 23
10.7 Measurement of thickness of oversheath . 23
10.7.1 General . 23
10.7.2 Requirements for the oversheath . 23
10.8 Measurement of thickness of metal sheath . 23
10.8.1 General . 23
10.8.2 General . 24
10.8.3 Strip method . 24
10.8.4 Ring method . 24
10.9 Measurement of diameters . 24
10.10 Hot set test for XLPE, EPR and HEPR insulations. 24
10.10.1 Procedure . 24
10.10.2 Requirements . 24
10.11 Measurement of capacitance . 25
10.12 Tests on components of cables with a longitudinally applied metal tape or
foil, bonded to the oversheath . 25
10.13 Examination of completed cable . 25
11 Sample tests on accessories . 25
11.1 Factory joints . 25
11.1.1 General . 25
11.1.2 PD measurement and AC voltage test . 25
11.1.3 Lightning impulse voltage test . 25
11.1.4 Hot set test for insulation . 25
11.1.5 Tensile test . 26
11.1.6 Joint inspection . 26
11.1.7 Pass criteria . 26
11.2 Sample tests on repair (field) joints and terminations . 26
11.2.1 Tests on components . 26
11.2.2 Tests on complete accessory . 26
12 Type tests on cable systems . 27
12.1 General . 27
12.2 Range of type approval . 27
12.3 Summary of type tests . 29
12.4 Mechanical tests . 29
12.4.1 Coiling test . 29
12.4.2 Tensile bending test . 32
12.4.3 Tensile test . 34
12.5 Electrical type tests . 35
12.5.1 Test voltage values . 35
12.5.2 Electrical type tests and sequence of tests . 35
12.5.3 Partial discharge tests . 36
12.5.4 Tan δ measurement . 36
12.5.5 Heating cycle voltage test .
...