IEC 60840:2020

IEC 60840 ®
Edition 5.0 2020-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Power cables with extruded insulation and their accessories for rated voltages
above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and
requirements
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IEC 60840 ®
Edition 5.0 2020-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Power cables with extruded insulation and their accessories for rated voltages

above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and

requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.060.20 ISBN 978-2-8322-8381-3

– 2 – IEC 60840:2020 RLV © IEC 2020
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 15
3.1 Definitions of dimensional values (thicknesses, cross-sections, etc.) . 15
3.2 Definitions concerning tests . 15
3.3 Other definitions . 16
4 Voltage designations, materials and rounding of numbers . 17
4.1 Rated voltages . 17
4.2 Cable insulating materials compounds . 17
4.3 Cable metal screens/sheaths . 17
4.4 Cable oversheathing materials compounds . 18
4.5 Rounding of numbers . 18
5 Precautions against water penetration in cables . 18
6 Cable characteristics . 19
7 Accessories characteristics . 20
7.1 Gas immersed cable terminations . 20
7.2 Composite insulators for outdoor cable terminations . 20
7.3 Accessory characteristics to be declared . 20
8 Test conditions . 21
8.1 Ambient temperature. 21
8.2 Frequency and waveform of power frequency test voltages .
8.2 High voltage tests . 21
8.3 Waveform of lightning impulse test voltages . 21
8.4 Relationship of test voltages to rated voltages . 21
8.5 Determination of the cable conductor temperature . 22
9 Routine tests on cables and on the main insulation of prefabricated accessories . 22
9.1 General . 22
9.2 Partial discharge test . 22
9.3 Voltage test . 23
9.4 Electrical test on oversheath of the cable . 23
10 Sample tests on cables . 23
10.1 General . 23
10.2 Frequency of tests . 23
10.3 Repetition of tests . 23
10.4 Conductor examination . 24
10.5 Measurement of electrical resistance of conductor and metal screen . 24
10.6 Measurement of thickness of cable insulation and oversheath . 24
10.6.1 General . 24
10.6.2 Requirements for the insulation . 25
10.6.3 Requirements for the cable oversheath . 25
10.7 Measurement of thickness of metal sheath . 25
10.7.1 General . 25
10.7.2 Lead or lead alloy sheath . 26

10.7.3 Plain or corrugated Copper or aluminium sheath . 26
10.7.4 Metal tape for CD design . 27
10.8 Measurement of diameters . 27
10.9 Hot set test for XLPE, EPR and HEPR insulations. 27
10.9.1 Procedure . 27
10.9.2 Requirements . 27
10.10 Measurement of capacitance . 27
10.11 Measurement of density of HDPE insulation . 27
10.11.1 Procedure . 27
10.11.2 Requirements . 27
10.12 Lightning impulse voltage test . 27
10.13 Water penetration test . 28
10.14 Additional tests on components of cables with a longitudinally applied metal
tape or foil, bonded to the oversheath . 28
11 Sample tests on accessories . 28
11.1 Tests on components of accessory . 28
11.2 Tests on complete accessory . 28
12 Type tests on cable systems . 29
12.1 General . 29
12.2 Range of type approval . 29
12.3 Summary of type tests . 31
12.4 Electrical type tests on complete cable systems . 31
12.4.1 Test voltage values . 31
12.4.2 Tests and sequence of tests . 32
12.4.3 Bending test . 32
12.4.4 Partial discharge tests . 33
12.4.5 Tan δ measurement . 34
12.4.6 Heating cycle voltage test . 34
12.4.7 Lightning impulse voltage test followed by a power frequency voltage
test . 35
12.4.8 Examination . 35
12.4.9 Resistivity of semi-conducting screens . 35
12.5 Non-electrical type tests on cable components and on complete cable . 36
12.5.1 General . 36
12.5.2 Check of cable construction . 36
12.5.3 Tests for determining the mechanical properties of insulation before and
after ageing . 36
12.5.4 Tests for determining the mechanical properties of oversheaths before
and after ageing . 37
12.5.5 Ageing tests on pieces of complete cable to check compatibility of
materials . 37
12.5.6 Loss of mass test on PVC oversheaths of type ST . 38
12.5.7 Pressure test at high temperature on oversheaths . 38
12.5.8 Test on PVC oversheaths (ST ST ) and LSHF oversheaths (ST ) at
1, 2 12
low temperature . 39
12.5.9 Heat shock test for PVC oversheaths (ST and ST ) . 39
1 2
12.5.10 Ozone resistance test for EPR and HEPR insulations . 39
12.5.11 Hot set test for EPR, HEPR and XLPE insulations . 39
12.5.12 Measurement of density of HDPE insulation . 40

– 4 – IEC 60840:2020 RLV © IEC 2020
12.5.13 Measurement of carbon black content of black PE oversheaths (ST
and ST ) . 40
12.5.14 Test under fire conditions . 40
12.5.15 Water penetration test . 41
12.5.16 Tests on components of cables with a longitudinally applied metal tape
or foil, bonded to the oversheath . 41
12.5.17 Shrinkage test for PE, HDPE and XLPE insulations . 41
12.5.18 Shrinkage test for PE oversheaths (ST , ST ) and LSHF oversheaths
3 7
(ST12) . 42
12.5.19 Determination of hardness of HEPR insulation . 42
12.5.20 Determination of the elastic modulus of HEPR insulation . 42
13 Prequalification test of the cable system . 42
13.1 General and range of prequalification test approval . 42
13.2 Prequalification test on complete system . 43
13.2.1 Summary of prequalification tests . 43
13.2.2 Test voltage values . 44
13.2.3 Test arrangement . 44
13.2.4 Heating cycle voltage test . 45
13.2.5 Lightning impulse voltage test . 46
13.2.6 Examination . 46
13.3 Tests for the extension of the prequalification of a cable system . 46
13.3.1 Summary of the extension of prequalification test . 46
13.3.2 Electrical part of the extension of prequalification tests on complete
cable system . 46
14 Type tests on cables . 48
14.1 General . 48
14.2 Range of type approval . 49
14.3 Summary of type tests . 49
14.4 Electrical type tests on completed cables . 50
15 Type tests on accessories . 50
15.1 General . 50
15.2 Range of type approval . 50
15.3 Summary of type tests . 51
15.4 Electrical type tests on accessories . 52
15.4.1 Test voltage values . 52
15.4.2 Tests and sequence of tests . 52
16 Electrical tests after installation . 52
16.1 General . 52
16.2 DC voltage test of the oversheath . 52
16.3 AC voltage test of the insulation . 53
Annex A (informative) Determination of the cable conductor temperature . 66
A.1 Purpose . 66
A.2 Calibration of the temperature of the main test loop . 66
A.2.1 General . 66
A.2.2 Installation of cable and temperature sensors . 66
A.2.3 Calibration method . 68
A.3 Heating for the test . 68
A.3.1 Method 1 – Test using a reference cable . 68

A.3.2 Method 2 – Test using conductor temperature calculations and
measurement of the surface temperature . 69
Annex B (normative) Rounding of numbers . 71
Annex C (informative) List of type, prequalification and extension of prequalification
tests for cable systems, cables and accessories . 72
Annex D (normative) Method of measuring resistivity of semi-conducting screens . 75
Annex E (normative) Water penetration test . 78
E.1 Test piece . 78
E.2 Test . 78
E.3 Requirements . 79
Annex F (normative) Test for water penetration in the conductor . 83
F.1 Test piece . 83
F.2 Test . 83
F.3 Requirements . 83
Annex G (normative) Tests on components of cables with a longitudinally applied
metal tape or foil, bonded to the oversheath . 87
G.1 Visual examination . 87
G.2 Adhesion and peel strength. 87
G.2.1 General . 87
G.2.2 Test: Adhesion strength . 87
G.2.3 Test: Peel strength of overlapped metal foil . 88
G.2.4 Requirements . 89
Annex H (normative) Additional tests for accessories . 91
H.1 General . 91
H.2 Range of approval. 92
H.2.1 Range of approval for joints without screen or metal sheath interruption . 92
H.2.2 Range of approval for joints with screen or metal sheath interruption . 92
H.2.3 Range of approval for accessories for cable screen interruption and/or
earth connection . 92
H.2.4 Range of approval for terminations with sectionalizing insulation . 93
H.3 Tests of joints with or without screen or metal sheath interruption and
accessories for cable screen interruption and/or earth connection . 93
H.3.1 Water immersion . 93
H.3.2 Electrical tests . 93
H.4 Tests of terminations with sheath sectionalizing insulation . 95
H.4.1 DC voltage withstand test between screen and earth . 95
H.4.2 Lightning impulse voltage withstand test between screen and earth . 95
H.5 Examination . 95
H.6 Tests for composite insulators for outdoor terminations . 96
H.6.1 General . 96
H.6.2 Internal pressure test . 96
H.6.3 Cantilever load test . 96
Annex I (normative) Determination of hardness of HEPR insulations . 97
I.1 Test piece . 97
I.2 Test procedure . 97
I.2.1 General . 97
I.2.2 Surfaces of large radius of curvature . 97
I.2.3 Surfaces of small radius of curvature . 97
I.2.4 Conditioning and test temperature . 97

– 6 – IEC 60840:2020 RLV © IEC 2020
I.2.5 Number of measurements . 98
Annex J (informative) Guidance on examination of cable and accessories . 99
Annex K (XXX) Void . 100
Bibliography . 101

Figure 1 – Example of the test arrangement for the prequalification test . 45
Figure 2 – Example of extension of prequalification test arrangement for the
prequalification of a system with another joint, designed for rigid as well as flexible
installation . 47
Figure A.1 – Typical test set-up for the reference loop and the main test loop . 67
Figure A.2 – Example of an arrangement of the temperature sensors on the conductor
of the reference loop . 68
Figure D.1 – Preparation of samples for measurement of resistivity of conductor and
insulation screens . 77
Figure E.1 – Schematic diagram of apparatus for water penetration test . 79
Figure F.1 – Schematic diagram of apparatus for water penetration test in the
conductor . 84
Figure G.1 – Adhesion of metal tape or foil . 88
Figure G.2 – Example of overlapped metal foil . 89
Figure G.3 – Peel strength of overlapped metal foil . 89
Figure G.4 – Typical strength versus grip spacing curve (1) . 90
Figure G.5 – Typical strength versus grip spacing curve (2) . 90
Figure I.1 – Test on surfaces of large radius of curvature . 98
Figure I.2 – Test on surfaces of small radius of curvature . 98

Table 1 – Insulating compounds for cables . 53
Table 2 – Oversheathing compounds for cables . 53
Table 3 – Tan δ requirements for insulating compounds for cables . 54
Table 4 – Test voltages . 54
Table 5 – Non-electrical type tests for insulating and oversheathing compounds for
cables . 55
Table 6 – Test requirements for mechanical characteristics of insulating compounds for
cables (before and after ageing) . 57
Table 7 – Test requirements for mechanical characteristics of oversheathing
compounds for cables (before and after ageing) . 59
Table 8 – Test requirements for particular characteristics of insulating compounds for
cables . 61
Table 9 – Test requirements for particular characteristics of PVC and LSHF
oversheathing for cables . 63
Table 10 – Maximum mechanical load for composite insulators for outdoor terminations . 65
Table C.1 – Type tests on cable systems, on cables and on accessories . 73
Table C.2 – Prequalification tests on cable systems with a calculated nominal
conductor electric stress above 8,0 kV/mm or a calculated nominal insulation electric
stress above 4,0 kV/mm . 73
Table C.3 – Extension of prequalification tests on cable systems with a calculated
nominal conductor electric stress above 8,0 kV/mm or a calculated nominal insulation
electric stress above 4,0 kV/mm . 74

Table G.1 – Minimum acceptable adhesion or peel strength forces . 90
Table H.1 – Test sequence . 91
Table H.2 – Lightning impulse voltage withstand test between screen and earth of
joints with or without screen or metal sheath interruption and accessories for cable
screen interruption and/or earth connection . 94
Table H.3 – Lightning impulse voltage withstand test between screen and screen of
joints with screen or metal sheath interruption and accessories for cable screen
interruption and/or earth connection . 95
Table H.4 – Lightning impulse voltage withstand tests between screen and earth of
terminations with sheath sectionalizing insulation . 95

– 8 – IEC 60840:2020 RLV © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER CABLES WITH EXTRUDED INSULATION
AND THEIR ACCESSORIES FOR RATED VOLTAGES
ABOVE 30 kV (U = 36 kV) UP TO 150 kV (U = 170 kV) –
m m
TEST METHODS AND REQUIREMENTS
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
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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. A vertical bar appears in the margin wherever a change has
been made. Additions are in green text, deletions are in strikethrough red text.

International Standard IEC 60840 has been prepared by IEC technical committee 20: Electric
cables.
This fifth edition cancels and replaces the fourth edition, published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• Gas immersed cable terminations for use at rated voltages above 52 kV are required to be
designed, type and routine tested in accordance with IEC 62271-209 in addition to the
routine and type tests specified in this document.
• Requirements are introduced for composite outdoor termination insulators.
• The test cylinder diameters specified for the bending test (type and prequalification tests)
have been modified in line with IEC TR 61901:2016.
• A low smoke halogen free oversheath material, designated ST is introduced.
• Additional tests under fire conditions are introduced: vertical flame spread, smoke density,
acidity and conductivity, which shall be applied according to the fire performance declared
for the cable.
• A test for water penetration in the conductor is added.
• In addition to tests on the outer protection of joints, type tests on the screen sectionalizing
insulation of all accessories have been introduced.
NOTE For a more detailed history of events leading up to this fifth edition, see the Introduction.
The text of this International Standard is based on the following documents:
FDIS Report on voting
20/1909/FDIS 20/1910/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.
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.

The contents of the corrigendum of February 2021 have been included in this copy.

– 10 – IEC 60840:2020 RLV © IEC 2020
INTRODUCTION
The first edition of IEC 60840, published in 1988, dealt only with cables. Accessories were
added to the second edition, published in February 1999, which separately covered test
methods and test requirements for
a) cables alone,
b) cables together with accessories (a cable system).
Some countries then suggested that a better discrimination be made between systems, cables
and accessories, particularly for the lower voltages of the scope, for example 45 kV. This was
taken into account in the third edition (2004) and is has been retained in this revision, which
gives subsequently, giving the type approval requirements and the range of approvals for:
a) cable systems,
b) cables alone,
c) accessories alone.
Manufacturers and users may choose the most appropriate option for type approval.
At its meeting in November 2004, TC 20 decided to prepare a further major revision of
IEC 60840 and concluded that this edition should incorporate the recommendations for testing
HV and EHV extruded cables that were under preparation by CIGRE study committee B1 WG
B1.06. This work was made available as CIGRE technical brochure No. 303, before the meeting
of TC 20 in October 2006. The brochure, entitled “Revision of qualification procedures for
extruded (extra) high voltage a.c. underground cables”, has therefore been considered by TC
20, and considerable parts implemented in this standard. Cables with high electrical stresses
at the conductor screen and/or insulation screen are now required to undergo a prequalification
test procedure (simplified compared to that in IEC 62067) as a cable system inclusive of
accessories.
The fourth edition (2011) introduced the prequalification test procedure, as a cable system
inclusive of accessories, for cables with high electrical stresses at the conductor screen and/or
insulation screen.
Additionally the following other significant changes to this standard have been introduced Other
significant changes in the fourth edition were:
a) The clause numbering of this document and IEC 62067 (which has been revised at the same
time as this standard) has been was coordinated to achieve as much commonality as
possible to assist users who use both standards.
b) In the case of the sample test, the lightning impulse voltage test is no longer followed by a
power frequency voltage test.
In this fifth edition the principle changes are as follows:
a) New definitions have been added for three different cable screen designs following
IEC TR 61901:2016.
b) Gas immersed cable terminations for use at rated voltages above 52 kV are required to be
designed, type and routine tested in accordance with IEC 62271-209 in addition to the
routine and type tests specified in this document.
c) Requirements are introduced for composite outdoor termination insulators.
d) The test cylinder diameters specified for the bending test (type and prequalification tests)
have been modified in line with IEC TR 61901:2016.
e) A low smoke halogen free oversheath material, designated ST is introduced.
f) Additional tests under fire conditions are introduced: vertical flame spread, smoke density,
acidity and conductivity, which are applied according to the fire performance declared for
the cable.
g) A test for water penetration in the conductor is added.
h) In addition to tests on the outer protection of joints, type tests on the screen sectionalizing
insulation of all accessories have been introduced.
i) A list of relevant CIGRE references is given in the bibliography.

– 12 – IEC 60840:2020 RLV © IEC 2020
POWER CABLES WITH EXTRUDED INSULATION
AND THEIR ACCESSORIES FOR RATED VOLTAGES
ABOVE 30 kV (U = 36 kV) UP TO 150 kV (U = 170 kV) –
m m
TEST METHODS AND REQUIREMENTS
1 Scope
This document specifies test methods and requirements for power cable systems, cables alone
and accessories alone, for fixed installations and for rated voltages above 30 kV (U = 36 kV)
m
up to and including 150 kV (U = 170 kV).
m
The requirements apply to single-core cables and to individually screened three-core cables
and to their accessories for usual conditions of installation and operation, but not to special
cables, such as submarine cables and their accessories, for which modifications to the standard
tests may be necessary or the setup of special test conditions may need to can be devised can
be necessary.
This document does not cover transition joints between cables with extruded insulation and
paper insulated cables.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
NOTE The IEC 60811 series is currently undergoing a revision, which will lead to a restructuring of its parts. A
description of this, as well as a cross-reference table between the current and planned parts will be given in
IEC 60811-100.
IEC 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60183, Guide to the selection of high-voltage cables
IEC 60228, Conductors of insulated cables
IEC 60229:2007, Electric cables – Tests on extruded oversheaths with a special protective
function
IEC 60230, Impulse tests on cables and their accessories
IEC 60287-1-1:2006, Electric cables – Calculation of the current rating – Part 1-1: Current rating
equations (100 % load factor) and calculation of losses – General
IEC 60332-1-2, Tests on electric and optical fibre cables under fire conditions – Part 1-2: Test
for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW
pre-mixed flame
IEC 60332-3-24, Tests on electric and optical fibre cables under fire conditions – Part 3-24:
Test for vertical flame spread of vertically-mounted bunched wires or cables – Category C

IEC 60754-2, Test on gases evolved during combustion of materials from cables – Part 2:
Determination of acidity (by pH measurement) and conductivity
IEC 60811-1-1:1993, Common test methods for insulating and sheathing materials of electric
cables – Part 1: Methods for general application – Section 1: Measurement of thickness and
overall dimensions – Tests for determining the mechanical properties
Amendment 1 (2001)
IEC 60811-1-2:1985, Common test methods for insulating and sheathing mat
...

IEC 60840 ®
Edition 5.0 2020-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Power cables with extruded insulation and their accessories for rated voltages
above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and
requirements
Câbles d'énergie à isolation extrudée et leurs accessoires pour des tensions
assignées supérieures à 30 kV (Um = 36 kV) et jusqu'à 150 kV (Um = 170 kV) –
Méthodes et exigences d'essai
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IEC 60840 ®
Edition 5.0 2020-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Power cables with extruded insulation and their accessories for rated voltages

above 30 kV (Um = 36 kV) up to 150 kV (Um = 170 kV) – Test methods and

requirements
Câbles d'énergie à isolation extrudée et leurs accessoires pour des tensions

assignées supérieures à 30 kV (Um = 36 kV) et jusqu'à 150 kV (Um = 170 kV) –

Méthodes et exigences d'essai
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.060.20 ISBN 978-2-8322-8302-8

– 2 – IEC 60840:2020 © IEC 2020
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 13
3.1 Definitions of dimensional values (thicknesses, cross-sections, etc.) . 13
3.2 Definitions concerning tests . 13
3.3 Other definitions . 14
4 Voltage designations, materials and rounding of numbers . 15
4.1 Rated voltages . 15
4.2 Cable insulating compounds . 15
4.3 Cable metal screens/sheaths . 15
4.4 Cable oversheathing compounds . 16
4.5 Rounding of numbers . 16
5 Precautions against water penetration in cables . 16
6 Cable characteristics . 17
7 Accessories characteristics . 18
7.1 Gas immersed cable terminations . 18
7.2 Composite insulators for outdoor cable terminations . 18
7.3 Accessory characteristics to be declared . 18
8 Test conditions . 19
8.1 Ambient temperature. 19
8.2 High voltage tests . 19
8.3 Waveform of lightning impulse test voltages . 19
8.4 Relationship of test voltages to rated voltages . 19
8.5 Determination of the cable conductor temperature . 19
9 Routine tests on cables and accessories . 19
9.1 General . 19
9.2 Partial discharge test . 20
9.3 Voltage test . 20
9.4 Electrical test on oversheath of the cable . 21
10 Sample tests on cables . 21
10.1 General . 21
10.2 Frequency of tests . 21
10.3 Repetition of tests . 21
10.4 Conductor examination . 21
10.5 Measurement of electrical resistance of conductor and metal screen . 22
10.6 Measurement of thickness of cable insulation and oversheath . 22
10.6.1 General . 22
10.6.2 Requirements for the insulation . 22
10.6.3 Requirements for the cable oversheath . 23
10.7 Measurement of thickness of metal sheath . 23
10.7.1 General . 23
10.7.2 Lead or lead alloy sheath . 23
10.7.3 Copper or aluminium sheath . 24

10.7.4 Metal tape for CD design . 24
10.8 Measurement of diameters . 24
10.9 Hot set test for XLPE, EPR and HEPR insulations. 24
10.9.1 Procedure . 24
10.9.2 Requirements . 24
10.10 Measurement of capacitance . 25
10.11 Measurement of density of HDPE insulation . 25
10.11.1 Procedure . 25
10.11.2 Requirements . 25
10.12 Lightning impulse voltage test . 25
10.13 Water penetration test . 25
10.14 Additional tests on components of cables with a longitudinally applied metal
tape or foil, bonded to the oversheath . 25
11 Sample tests on accessories . 26
11.1 Tests on components of accessory . 26
11.2 Tests on complete accessory . 26
12 Type tests on cable systems . 26
12.1 General . 26
12.2 Range of type approval . 27
12.3 Summary of type tests . 28
12.4 Electrical type tests on cable systems . 28
12.4.1 Test voltage values . 28
12.4.2 Tests and sequence of tests . 29
12.4.3 Bending test . 29
12.4.4 Partial discharge tests . 30
12.4.5 Tan δ measurement . 30
12.4.6 Heating cycle voltage test . 30
12.4.7 Lightning impulse voltage test followed by a power frequency voltage
test . 31
12.4.8 Examination . 31
12.4.9 Resistivity of semi-conducting screens . 32
12.5 Non-electrical type tests on cable components and on complete cable . 32
12.5.1 General . 32
12.5.2 Check of cable construction . 33
12.5.3 Tests for determining the mechanical properties of insulation before and
after ageing . 33
12.5.4 Tests for determining the mechanical properties of oversheaths before
and after ageing . 33
12.5.5 Ageing tests on pieces of complete cable to check compatibility of
materials . 34
12.5.6 Loss of mass test on PVC oversheaths of type ST . 34
12.5.7 Pressure test at high temperature on oversheaths . 34
12.5.8 Test on PVC oversheaths (ST , ST ) and LSHF oversheaths (ST ) at
1 2 12
low temperature . 35
12.5.9 Heat shock test for PVC oversheaths (ST and ST ) . 35
1 2
12.5.10 Ozone resistance test for EPR and HEPR insulations . 35
12.5.11 Hot set test for EPR, HEPR and XLPE insulations . 35
12.5.12 Measurement of density of HDPE insulation . 35

– 4 – IEC 60840:2020 © IEC 2020
12.5.13 Measurement of carbon black content of black PE oversheaths (ST
and ST ) . 36
12.5.14 Test under fire conditions . 36
12.5.15 Water penetration test . 37
12.5.16 Tests on components of cables with a longitudinally applied metal tape
or foil, bonded to the oversheath . 37
12.5.17 Shrinkage test for PE, HDPE and XLPE insulations . 37
12.5.18 Shrinkage test for PE oversheaths (ST , ST ) and LSHF oversheaths
3 7
(ST ) . 37
12.5.19 Determination of hardness of HEPR insulation . 38
12.5.20 Determination of the elastic modulus of HEPR insulation . 38
13 Prequalification test of the cable system . 38
13.1 General and range of prequalification test approval . 38
13.2 Prequalification test on complete system . 39
13.2.1 Summary of prequalification tests . 39
13.2.2 Test voltage values . 39
13.2.3 Test arrangement . 39
13.2.4 Heating cycle voltage test . 40
13.2.5 Lightning impulse voltage test . 41
13.2.6 Examination . 41
13.3 Tests for the extension of the prequalification of a cable system . 41
13.3.1 Summary of the extension of prequalification test . 41
13.3.2 Electrical part of the extension of prequalification tests on complete
cable system . 41
14 Type tests on cables . 43
14.1 General . 43
14.2 Range of type approval . 44
14.3 Summary of type tests . 44
14.4 Electrical type tests on completed cables . 45
15 Type tests on accessories . 45
15.1 General . 45
15.2 Range of type approval . 45
15.3 Summary of type tests . 46
15.4 Electrical type tests on accessories . 47
15.4.1 Test voltage values . 47
15.4.2 Tests and sequence of tests . 47
16 Electrical tests after installation . 47
16.1 General . 47
16.2 DC voltage test of the oversheath . 47
16.3 AC voltage test of the insulation . 47
Annex A (informative) Determination of the cable conductor temperature . 55
A.1 Purpose . 55
A.2 Calibration of the temperature of the main test loop . 55
A.2.1 General . 55
A.2.2 Installation of cable and temperature sensors . 55
A.2.3 Calibration method . 57
A.3 Heating for the test . 57
A.3.1 Method 1 – Test using a reference cable . 57

A.3.2 Method 2 – Test using conductor temperature calculations and
measurement of the surface temperature . 58
Annex B (normative) Rounding of numbers . 59
Annex C (informative) List of type, prequalification and extension of prequalification
tests for cable systems, cables and accessories . 60
Annex D (normative) Method of measuring resistivity of semi-conducting screens . 62
Annex E (normative) Water penetration test . 65
E.1 Test piece . 65
E.2 Test . 65
E.3 Requirements . 66
Annex F (normative) Test for water penetration in the conductor . 67
F.1 Test piece . 67
F.2 Test . 67
F.3 Requirements . 67
Annex G (normative) Tests on components of cables with a longitudinally applied
metal tape or foil, bonded to the oversheath . 69
G.1 Visual examination . 69
G.2 Adhesion and peel strength. 69
G.2.1 General . 69
G.2.2 Test: Adhesion strength . 69
G.2.3 Test: Peel strength of overlapped metal foil . 70
G.2.4 Requirements . 71
Annex H (normative) Additional tests for accessories . 73
H.1 General . 73
H.2 Range of approval. 74
H.2.1 Range of approval for joints without screen or metal sheath interruption . 74
H.2.2 Range of approval for joints with screen or metal sheath interruption . 74
H.2.3 Range of approval for accessories for cable screen interruption and/or
earth connection . 74
H.2.4 Range of approval for terminations with sectionalizing insulation . 75
H.3 Tests of joints with or without screen or metal sheath interruption and
accessories for cable screen interruption and/or earth connection . 75
H.3.1 Water immersion . 75
H.3.2 Electrical tests . 75
H.4 Tests of terminations with sheath sectionalizing insulation . 77
H.4.1 DC voltage withstand test between screen and earth . 77
H.4.2 Lightning impulse voltage withstand test between screen and earth . 77
H.5 Examination . 77
H.6 Tests for composite insulators for outdoor terminations . 78
H.6.1 General . 78
H.6.2 Internal pressure test . 78
H.6.3 Cantilever load test . 78
Annex I (normative) Determination of hardness of HEPR insulations . 79
I.1 Test piece . 79
I.2 Test procedure . 79
I.2.1 General . 79
I.2.2 Surfaces of large radius of curvature . 79
I.2.3 Surfaces of small radius of curvature . 79
I.2.4 Conditioning and test temperature . 79

– 6 – IEC 60840:2020 © IEC 2020
I.2.5 Number of measurements . 80
Annex J (informative) Guidance on examination of cable and accessories . 81
Annex K (normative) Methods of determining the weighted value of the cable for
measurement of halogen content . 82
K.1 Calculating the weighted value of the cable when the halogen content of
individual materials is tested . 82
K.2 Preparation of the test sample for measurement of halogen content on a
sample representative of the cable construction . 82
Bibliography . 83

Figure 1 – Example of the test arrangement for the prequalification test . 40
Figure 2 – Example of extension of prequalification test arrangement for the
prequalification of a system with another joint, designed for rigid as well as flexible
installation . 42
Figure A.1 – Typical test set-up for the reference loop and the main test loop . 56
Figure A.2 – Example of an arrangement of the temperature sensors on the conductor
of the reference loop . 57
Figure D.1 – Preparation of samples for measurement of resistivity of conductor and
insulation screens . 64
Figure E.1 – Schematic diagram of apparatus for water penetration test . 66
Figure F.1 – Schematic diagram of apparatus for water penetration test in the
conductor . 68
Figure G.1 – Adhesion of metal tape or foil . 70
Figure G.2 – Example of overlapped metal foil . 71
Figure G.3 – Peel strength of overlapped metal foil . 71
Figure G.4 – Typical strength versus grip spacing curve (1) . 72
Figure G.5 – Typical strength versus grip spacing curve (2) . 72
Figure I.1 – Test on surfaces of large radius of curvature . 80
Figure I.2 – Test on surfaces of small radius of curvature . 80

Table 1 – Insulating compounds for cables . 48
Table 2 – Oversheathing compounds for cables . 48
Table 3 – Tan δ requirements for insulating compounds for cables . 48
Table 4 – Test voltages . 49
Table 5 – Non-electrical type tests for insulating and oversheathing compounds for
cables . 49
Table 6 – Test requirements for mechanical characteristics of insulating compounds for
cables (before and after ageing) . 50
Table 7 – Test requirements for mechanical characteristics of oversheathing
compounds for cables (before and after ageing) . 51
Table 8 – Test requirements for particular characteristics of insulating compounds for
cables . 52
Table 9 – Test requirements for particular characteristics of PVC and LSHF
oversheathing for cables . 53
Table 10 – Maximum mechanical load for composite insulators for outdoor terminations . 54
Table C.1 – Type tests on cable systems, on cables and on accessories . 60

Table C.2 – Prequalification tests on cable systems with a calculated nominal
conductor electric stress above 8,0 kV/mm or a calculated nominal insulation electric
stress above 4,0 kV/mm . 61
Table C.3 – Extension of prequalification tests on cable systems with a calculated
nominal conductor electric stress above 8,0 kV/mm or a calculated nominal insulation
electric stress above 4,0 kV/mm . 61
Table G.1 – Minimum acceptable adhesion or peel strength forces . 72
Table H.1 – Test sequence . 73
Table H.2 – Lightning impulse voltage withstand test between screen and earth of
joints with or without screen or metal sheath interruption and accessories for cable
screen interruption and/or earth connection . 76
Table H.3 – Lightning impulse voltage withstand test between screen and screen of
joints with screen or metal sheath interruption and accessories for cable screen
interruption and/or earth connection . 77
Table H.4 – Lightning impulse voltage withstand tests between screen and earth of
terminations with sheath sectionalizing insulation . 77

– 8 – IEC 60840:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER CABLES WITH EXTRUDED INSULATION
AND THEIR ACCESSORIES FOR RATED VOLTAGES
ABOVE 30 kV (U = 36 kV) UP TO 150 kV (U = 170 kV) –
m m
TEST METHODS AND REQUIREMENTS
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,
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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 60840 has been prepared by IEC technical committee 20: Electric
cables.
This fifth edition cancels and replaces the fourth edition, published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• Gas immersed cable terminations for use at rated voltages above 52 kV are required to be
designed, type and routine tested in accordance with IEC 62271-209 in addition to the
routine and type tests specified in this document.
• Requirements are introduced for composite outdoor termination insulators.
• The test cylinder diameters specified for the bending test (type and prequalification tests)
have been modified in line with IEC TR 61901:2016.
• A low smoke halogen free oversheath material, designated ST is introduced.
• Additional tests under fire conditions are introduced: vertical flame spread, smoke density,
acidity and conductivity, which shall be applied according to the fire performance declared
for the cable.
• A test for water penetration in the conductor is added.
• In addition to tests on the outer protection of joints, type tests on the screen sectionalizing
insulation of all accessories have been introduced.
NOTE For a more detailed history of events leading up to this fifth edition, see the Introduction.
The text of this International Standard is based on the following documents:
FDIS Report on voting
20/1909/FDIS 20/1910/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.
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.
– 10 – IEC 60840:2020 © IEC 2020
INTRODUCTION
The first edition of IEC 60840, published in 1988, dealt only with cables. Accessories were
added to the second edition, published in February 1999, which separately covered test
methods and test requirements for
a) cables alone,
b) cables together with accessories (a cable system).
Some countries then suggested that a better discrimination be made between systems, cables
and accessories, particularly for the lower voltages of the scope, for example 45 kV. This was
taken into account in the third edition (2004) and has been retained subsequently, giving the
type approval requirements and the range of approvals for:
a) cable systems,
b) cables alone,
c) accessories alone.
Manufacturers and users may choose the most appropriate option for type approval.
The fourth edition (2011) introduced the prequalification test procedure, as a cable system
inclusive of accessories, for cables with high electrical stresses at the conductor screen and/or
insulation screen.
Other significant changes in the fourth edition were:
a) The clause numbering of this document and IEC 62067 was coordinated to achieve as much
commonality as possible.
b) In the case of the sample test, the lightning impulse voltage test is no longer followed by a
power frequency voltage test.
In this fifth edition the principle changes are as follows:
a) New definitions have been added for three different cable screen designs following
IEC TR 61901:2016.
b) Gas immersed cable terminations for use at rated voltages above 52 kV are required to be
designed, type and routine tested in accordance with IEC 62271-209 in addition to the
routine and type tests specified in this document.
c) Requirements are introduced for composite outdoor termination insulators.
d) The test cylinder diameters specified for the bending test (type and prequalification tests)
have been modified in line with IEC TR 61901:2016.
e) A low smoke halogen free oversheath material, designated ST is introduced.
f) Additional tests under fire conditions are introduced: vertical flame spread, smoke density,
acidity and conductivity, which are applied according to the fire performance declared for
the cable.
g) A test for water penetration in the conductor is added.
h) In addition to tests on the outer protection of joints, type tests on the screen sectionalizing
insulation of all accessories have been introduced.
i) A list of relevant CIGRE references is given in the bibliography.

POWER CABLES WITH EXTRUDED INSULATION
AND THEIR ACCESSORIES FOR RATED VOLTAGES
ABOVE 30 kV (U = 36 kV) UP TO 150 kV (U = 170 kV) –
m m
TEST METHODS AND REQUIREMENTS
1 Scope
This document specifies test methods and requirements for power cable systems, cables alone
and accessories alone, for fixed installations and for rated voltages above 30 kV (U = 36 kV)
m
up to and including 150 kV (U = 170 kV).
m
The requirements apply to single-core cables and to individually screened three-core cables
and to their accessories for usual conditions of installation and operation, but not to special
cables, such as submarine cables and their accessories, for which modifications to the standard
tests or the setup of special test conditions can be necessary.
This document does not cover transition joints between cables with extruded insulation and
paper insulated cables.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60060-1:2010, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60228, Conductors of insulated cables
IEC 60229:2007, Electric cables – Tests on extruded oversheaths with a special protective
function
IEC 60230, Impulse tests on cables and their accessories
IEC 6
...