IEC 61535:2019

IEC 61535 ®
Edition 2.0 2019-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Installation couplers intended for permanent connection in fixed installations

Coupleurs d'installation pour connexions permanentes dans les installations
fixes
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IEC 61535 ®
Edition 2.0 2019-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Installation couplers intended for permanent connection in fixed installations

Coupleurs d'installation pour connexions permanentes dans les installations

fixes
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.99 ISBN 978-2-8322-7428-6

– 2 – IEC 61535:2019 © IEC 2019
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 General requirements . 12
5 Conditions for tests . 12
5.1 General . 12
5.2 Test conditions . 13
5.3 Tests on non-rewirable installation couplers . 13
5.4 Order of tests . 13
5.5 Specification of tests . 13
5.6 Compliance requirements . 13
5.7 Routine tests for non-rewirable installation couplers . 13
6 Ratings . 13
6.1 Rated voltage . 13
6.2 Rated current . 14
6.3 Rated connecting capacity . 14
6.4 Tests . 15
7 Classification . 15
8 Marking and documentation . 15
8.1 General . 15
8.2 Use of symbols or letters . 16
8.3 Markings . 16
8.4 Documentation . 17
9 Dangerous compatibility . 17
9.1 Unintended or improper connection . 17
9.2 Engagement . 18
9.3 Compatibility of different installation coupler systems . 18
9.4 Compatibility with standard systems . 18
10 Protection against electric shock . 18
10.1 Degree of protection against ingress of solid foreign objects . 18
10.2 Access to live parts . 19
10.3 External parts . 19
11 Terminals, terminations and connectable conductors . 19
11.1 Terminals and terminations . 19
11.1.1 General . 19
11.1.2 Terminals of rewirable installation couplers . 19
11.1.3 Terminations of non-rewirable installation couplers . 20
11.2 Connectable conductors. 20
12 Construction . 20
12.1 Earth connection . 20
12.2 Locking against rotation . 21
12.3 Mechanical strength of contacts . 21
12.4 Housing of rewirable installation couplers . 21

12.5 Housing of non-rewirable installation couplers . 21
12.6 Dismantling and opening of rewirable installation couplers . 21
12.7 Earthing contact and earthing terminal . 22
12.8 Loose conductor strands . 22
12.8.1 General . 22
12.8.2 Strand test for rewirable installation couplers . 22
12.8.3 Strand test for non-rewirable installation couplers . 23
12.8.4 Strand test for non-rewirable moulded-on installation couplers . 23
12.9 Incorporation of electrical devices . 23
12.10 Retaining means . 23
12.11 Distribution blocks . 24
12.12 Shrouds . 24
12.13 Factory wiring . 24
12.14 Stress test . 24
12.14.1 General . 24
12.14.2 Stress test of rewirable installation couplers . 24
12.14.3 Stress test of non-rewirable installation couplers . 24
12.15 Separation of non-rewirable installation couplers . 25
13 Protection against harmful ingress of solid foreign objects and against harmful
ingress of water . 25
13.1 General . 25
13.2 Protection against harmful ingress of solid foreign objects . 25
13.3 Protection against harmful ingress of water . 25
14 Insulation resistance and electric strength . 25
14.1 General . 25
14.2 Insulation resistance . 26
14.3 Electric strength . 26
15 Construction of contacts . 27
15.1 Resiliency . 27
15.2 Resistance of connections . 27
15.3 Contact pressure . 27
16 Temperature rise . 27
17 Breaking capacity . 28
18 Forces necessary to disengage the parts of the installation coupler . 29
19 Cables and their connection . 29
19.1 Capability of being fitted . 29
19.2 Relief from pull, thrust and torsion . 30
19.3 Relief . 30
19.4 Capability to connect cables with different cross-sectional area . 30
19.5 Sharp edges . 33
20 Mechanical strength . 33
21 Resistance to heat and ageing. 34
21.1 Resistance to heat . 34
21.2 Dry heat storage . 34
21.3 Ball pressure test . 34
21.4 Ageing of elastomeric and thermoplastic material . 35
21.5 Current cycling test . 35
22 Screws, current-carrying parts and connections . 36

– 4 – IEC 61535:2019 © IEC 2019
22.1 Screws and nuts . 36
22.2 Screws and insulating material . 37
22.3 Screws and rivets for electrical and mechanical connections. 38
22.4 Metals of current-carrying parts . 38
23 Clearances, creepage distances and distances through solid insulation . 38
24 Resistance to abnormal heat and to tracking . 41
24.1 Resistance to abnormal heat . 41
24.2 Resistance to tracking . 43
25 Resistance to rusting . 43
Annex A (normative)  Routine earth (PE) continuity tests . 45
Annex B (normative) Test circuits for temperature rise test . 46
Annex C (normative)  Number of sets of test samples used for the tests and sequence
of tests for each set . 49
Annex D (informative) Guide to use . 50
D.1 General . 50
D.2 Applications . 50
D.3 Use of installation couplers . 50
Annex E (normative) Warning symbol used in DC applications . 52
Bibliography . 53

Figure 1 – Apparatus for testing the cable anchorage . 32
Figure 2 – Apparatus for measuring the distortion (example) . 33
Figure 3 – Ball-pressure apparatus . 35
Figure 4 – Explanation of "small part" . 43
Figure B.1 – 1P + N + PE installation couplers, including N (left figure), including PE

(right figure) . 46
Figure B.2 – 3P + N + PE installation couplers, 3 phases loaded (left figure), N and PE
loaded (right figure) . 46
Figure B.3 – 1P + N + PE distribution block, phase and N loaded . 47
Figure B.4 – 1P + N + PE distribution block, phase and PE loaded . 47
Figure B.5 – 3P + N + PE to 1P + N + PE distribution block, 3 phases loaded . 48
Figure B.6 – 3P + N + PE to 1P + N + PE distribution block, N and PE loaded . 48
Figure D.1 – Examples of use of installation couplers . 51
Figure E.1 – Symbol "DO NOT CONNECT OR DISCONNECT UNDER LOAD" . 52

Table 1 – Voltage rating for installation couplers in AC application . 14
Table 2 – Voltage rating for installation couplers in DC application . 14
Table 3 – Classes of installation couplers . 15
Table 4 – Test currents for installation couplers . 28
Table 5 – Forces to be applied to cable anchorages . 31
Table 6 – Torque applied for the tightening and loosening test . 37
Table 7 – Installation couplers intended for use in supply systems with a maximum
voltage to earth of 150 V AC, rated impulse voltage 2,5 kV . 38
Table 8 – Installation couplers intended for use in supply systems with a maximum
voltage to earth of 300 V AC, rated impulse voltage 4,0 kV . 39

Table 9 – Installation couplers intended for use in single-phase two-wire systems
50 V DC and single-phase three-wire systems 60 V DC, rated impulse voltage 0,8 kV . 39
Table 10 – Installation couplers intended for use in single-phase two-wire systems
120 V DC and single-phase three-wire systems 240 V DC, rated impulse voltage
2,5 kV . 40
Table 11 – Installation couplers intended for use in single-phase two-wire systems
220 V DC and single-phase three-wire systems 440 V DC, rated impulse voltage

4,0 kV . 41
Table C.1 – Sets of samples . 49

– 6 – IEC 61535:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INSTALLATION COUPLERS INTENDED FOR PERMANENT
CONNECTION IN FIXED INSTALLATIONS

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
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6) All users should ensure that they have the latest edition of this publication.
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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 61535 has been prepared by IEC technical committee 23:
Electrical accessories.
This second edition cancels and replaces the first edition published in 2009 and
Amendment 1:2012. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) enlargement of the scope to DC application;
b) addition of further requirements as regards DC application (marking, etc.), no additional
test procedures were deemed necessary; however some modifications were necessary in
the normative text;
c) changes and enhancement of the field of application of installation couplers into outdoor
applications;
d) addition of a suitable temperature range;

e) updating of the list of normative references, modified to undated references, where
possible.
The text of this International Standard is based on the following documents:
CDV Report on voting
23/792/CDV 23/848/RVC
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.
In this standard, 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.
– 8 – IEC 61535:2019 © IEC 2019
INTRODUCTION
AC and DC installation couplers according to this document may be used, for example, in
prefabricated buildings, commercial showrooms, installation cavities, such as suspended
floors and ceilings, in partition walls and in any similar applications, or cable tray systems,
cable ladder systems, cable ducting systems and cable trunking systems or in furniture
complying with IEC 60364-7-713.
This document may be used as a guide for installation couplers with additional contacts for
voltages other than mains voltages.
Particular requirements for installation couplers, for example, for use at higher ambient
temperatures, with higher mechanical durability (e.g. metal housings), with higher fire
resistance and for use in control circuits (e.g. SELV), are under consideration.
National rules can have requirements concerning the accessibility of installation couplers.
National rules can specify who is allowed to carry out the connection and disconnection of
installation couplers.
National rules can have requirements concerning installation couplers with metal conduits.

INSTALLATION COUPLERS INTENDED FOR PERMANENT
CONNECTION IN FIXED INSTALLATIONS

1 Scope
This document applies to two-wire, up to five-wire installation couplers, including earth, if
provided, with a rated voltage up to and including 500 V AC or DC and a rated connecting
capacity up to and including 10 mm for permanent connection in electrical installations.
Installation couplers with additional contacts for voltages other than mains voltages are
outside the scope of this document.
An installation coupler consists of an installation female connector and an installation male
connector for permanent connection not intended to be engaged or disengaged under load
nor to be engaged or disengaged other than during first installation or during reconfiguration
or maintenance of the wiring system in which installation couplers have been installed. This
means that installation couplers are only intended for infrequent use.
Installation couplers are not suitable for use in place of socket-outlet systems. Installation
couplers are not suitable for use in place of devices for connecting luminaires (DCLs)
according to IEC 61995 (all parts) or in place of luminaire supporting couplers (LSCs).
Installation couplers complying with this document are suitable for use at ambient
temperatures not normally exceeding +40 °C, but their average over a period does not exceed
+35 °C, with a lower limit of the ambient air temperature of −5 °C, either for indoor or outdoor
use.
NOTE 1 Additional tests for use in cold climates are under consideration.
NOTE 2 For other temperatures, necessary information can be given in the manufacturer's installation
instructions.
In locations where special conditions prevail, as in ships, vehicles and the like and in
hazardous locations, for example where explosions are liable to occur, special constructions
can be required.
NOTE 3 Installation couplers are intended to be installed by instructed or skilled persons.
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 60068-2-31:2008, Environmental testing – Part 2-31: Tests – Test Ec: Rough handling
shocks, primarily for equipment-type specimens
IEC 60112, Method for the determination of the proof and the comparative tracking indices of
solid insulating materials
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60529:1989/AMD1:1999
IEC 60529:1989/AMD2:2013
– 10 – IEC 61535:2019 © IEC 2019
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60695-2-11, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products (GWEPT)
IEC 60998-2-3, Connecting devices for low-voltage circuits for household and similar
purposes – Part 2-3: Particular requirements for connecting devices as separate entities with
insulation-piercing clamping units
IEC 60999-1:1999, Connecting devices – Electrical copper conductors – Safety requirements
for screw-type and screwless-type clamping units – Part 1: General requirements and
2 2
particular requirements for clamping units for conductors from 0,2 mm up to 35 mm
(included)
IEC 61032:1997, Protection of persons and equipment by enclosures – Probes for verification
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
Where the terms "voltage" and "current" are used in this document, they are RMS values,
unless otherwise specified.
3.1
rated voltage
voltage assigned to the installation coupler by the manufacturer
3.2
rated current
maximum current assigned to the installation coupler by the manufacturer
Note 1 to entry: Rated current refers to the installation coupler itself and not to an electric circuit.
3.3
rated connecting capacity
cross-sectional area of the largest conductor(s) to be connected as stated by the
manufacturer of the installation coupler
3.4
permanent connection
connecting method in an installation which is only opened for maintenance or wiring system
re-configuration
Note 1 to entry: The expression "permanent connection" is to be understood as a connection which is maintained
as long as an installation exists.
3.5
installation coupler
connecting device consisting of an installation female connector and an installation male
connector provided with retaining means for permanent connection not intended to be
engaged or disengaged under load nor to be engaged or disengaged other than during first

installation, during maintenance of the wiring system or during re-configuration of the wiring
system
3.6
installation male connector
load side portion of an installation coupler which contains the male contacts
3.7
installation female connector
supply side portion of an installation coupler which contains the female contacts
3.8
installation coupler system
family of installation couplers consisting of one or more installation female connectors
compatible by mechanical coding features with one or more installation male connectors, with
the same ratings produced according to the specification of one manufacturer
Note 1 to entry: The meaning of one manufacturer is in this case of one and the same manufacturer.
3.9
wiring system
assembly made up of a cable or cables or busbars and the parts which secure and if
necessary enclose the cables or busbars
[SOURCE: IEC 60364-5-52:2009, 520.3.1, modified – "bare or insulated conductors" has
been replaced with "a cable".]
3.10
rewirable installation coupler
installation coupler so constructed that the cable can be replaced
3.11
non-rewirable installation coupler
installation coupler so constructed that it forms a complete unit with the cable after connection
and assembly by the manufacturer
Note 1 to entry: See also 12.14.
3.12
non-rewirable moulded-on installation coupler
non-rewirable installation coupler so constructed that the contacts, terminals or connections
and the attached cable ends are surrounded by insulating material manufactured by a
moulding process
3.13
non-rewirable non-moulded-on installation coupler
non-rewirable installation coupler so constructed that the contacts, terminals or connections
and the attached cable ends are surrounded by separate parts of insulating material
3.14
distribution block
device intended for branching of circuits
3.15
retaining means
arrangement by which an installation female connector and an installation male connector are
held in position when they are properly engaged and prevents unintentional disengagement
Note 1 to entry: The disengagement may be done by hand or by the use of a tool.

– 12 – IEC 61535:2019 © IEC 2019
3.16
cap
removable barrier to prevent ready accessibility to an unused installation female connector
3.17
routine test
test to which each device is subjected during and/or after manufacture to ascertain whether it
complies with certain criteria
3.18
type test
test of one or more devices made to a certain design to show that the design meets certain
requirements
3.19
readily accessible
accessibility to touch extending from any point on a surface where persons usually stand or
move about to the limits which a person can reach with the hand, in any direction without
assistance
Note 1 to entry: See IEC 60364-4-41:2005, Annex B.
3.20
terminal
part of an accessory to which a conductor is attached, providing a reusable connection
3.21
termination
part of an accessory to which a conductor is permanently attached
[SOURCE: IEC 60050-442:1998, 442-06-06]
4 General requirements
Installation couplers shall be so designed and constructed that, in normal use, their
performance is reliable and without danger to the user or damage to the surroundings.
Compliance is checked by carrying out all the relevant tests specified.
NOTE In the USA, these installation couplers are not permitted to be used where they will not be visible after
installation.
5 Conditions for tests
5.1 General
Tests shall be carried out to check compliance with the relevant requirements of this
document.
Only connectors (male and female) of one installation coupler system according to the
specification of one and the same manufacturer shall be mated together for carrying out the
test.
Tests are as follows:
– type tests shall be made on representative specimens of each type of installation coupler;
– routine tests shall be made on each installation coupler as required in this document.

Tests of 5.2 to 5.6 are applicable to type tests and 5.7 to routine tests.
NOTE In the UK, where installation couplers have more than 5 wires, they shall meet the requirements of
IEC 61535 as though they were included in the scope and shall be tested in such a way that all of the mains
voltage pins are subjected to the same level of testing.
5.2 Test conditions
Unless otherwise specified, the tests shall be carried out on specimens as delivered and
under conditions of normal use at an ambient temperature between 15 °C and 35 °C.
Where the value of the temperature is of importance, the test shall be carried out at
20 °C ± 5 °C.
5.3 Tests on non-rewirable installation couplers
For testing purposes, non-rewirable installation couplers shall be provided with cables of at
least 1 m length unless otherwise specified in this document.
5.4 Order of tests
If not otherwise specified in this document, the tests shall be carried out in the order of the
clauses/subclauses as specified in Table C.1.
5.5 Specification of tests
Installation male connectors, caps, installation female connectors and distribution blocks shall
be tested in connection with their matching counterparts complying with this document.
The sets of test specimens shall undergo the tests as specified in Table C.1.
5.6 Compliance requirements
Specimens are deemed not to comply with this document if there is more than one specimen
failure in any one of the tests.
If one specimen of a given set fails in a test due to an assembly or manufacturing fault, that
test and those preceding, which may have influenced the result of that test, are repeated on
another set of specimens of the same set number as specified in Table C.1, all of which shall
then comply with the repeated tests.
NOTE The applicant can submit, together with the specified number of specimens, the additional set of specimens
which can be required should one specimen fail. The testing station will then, without further request, test
additional specimens and will reject only if a further failure occurs. If the additional set of specimens is not
submitted at the same time as the specified number of specimens, the failure of one specimen will entail rejection.
5.7 Routine tests for non-rewirable installation couplers
Routine tests for non-rewirable installation couplers are specified in Annex A.
6 Ratings
6.1 Rated voltage
Installation couplers should preferably have a rated voltage chosen either from Table 1 for AC
application or from Table 2 for DC application.
All components of the same installation coupler system shall have the same phase to neutral
voltage rating.
– 14 – IEC 61535:2019 © IEC 2019
Table 1 – Voltage rating for installation couplers in AC application
Nominal voltage of Rated voltage Rated impulse voltage
power supply system
V V kV
100 125 2,5
100/200 125/250 2,5
230 250 4,0
230/400 250/400 4,0
277/480 320/500 4,0
Table 2 – Voltage rating for installation couplers in DC application
Nominal voltage of Rated voltage Rated impulse voltage
power supply system
V V kV
12 12 to be defined
60 60 to be defined
a b
120 to 240 125/250 2,5
a b
220 to 440 250/500 4,0
NOTE For DC applications up to 60 V, due to load switching, much higher voltages than the rated voltage are
also possible, therefore the complete circuit has to be considered when defining the rating for impulse
voltage.
a
Voltage live conductor against reference conductor / earth.
b
Voltage live conductor (+ / − polarity).

6.2 Rated current
Installation couplers should preferably have a rated current chosen from the following values:
– 10 A
– 13 A
– 16 A
– 20 A
– 25 A
– 32 A.
6.3 Rated connecting capacity
Installation couplers should preferably have a rated connecting capacity chosen from the
following values:
– 1,5 mm
– 2,5 mm
– 4 mm
– 6 mm
– 10 mm .
6.4 Tests
Compliance with 6.1, 6.2 and 6.3 is checked by inspection of markings according to Clause 8.
7 Classification
Installation couplers are classified according to Table 3.
Table 3 – Classes of installation couplers
Criterion Possible classes of installation couplers
7.1.1 2,5 kV
7.1 Rated impulse voltage
7.1.2 4 kV
7.2.1 Rewirable
7.2 Method of connecting the cable
7.2.2 Non-rewirable
7.3 Degree of protection against ingress of
solid foreign objects and ingress of
water according to IEC 60529 (IP-Code)
a
7.4.1 Readily accessible
7.4 Location where installation couplers
will be installed
7.4.2 Non-readily accessible
7.5.1 With earthing contact
7.5 Existence of an earthing contact
7.5.2 Without earthing contact
7.6.1 Solid
7.6.2 Rigid (solid and stranded)
7.6 Type of conductors to be connected
7.6.3 Flexible
7.6.4 Both rigid (solid and stranded) and flexible
7.7.1 Installation couplers with screw-type terminals
7.7 Type of terminals for rewirable
7.7.2 Installation couplers with screwless terminals
installation couplers only
7.7.3 Installation couplers with insulation piercing terminals
7.8.1 AC
7.8 Application
7.8.2 DC
a
Installation couplers for readily accessible areas can also be used in non-readily accessible areas.

8 Marking and documentation
8.1 General
Installation couplers shall be marke
...