SIST EN 62491:2008

Industrial systems, installations and equipment and industrial products - Labelling of cables and cores

IEC 62491:2008 provides rules and guidelines for the labelling of cables and cores/conductors used in industrial installations, equipment and products, in order to maintain a clear relation between the technical documentation and the actual equipment and for other purposes. International Standard IEC 62491 has been prepared by IEC technical committee 3: Information structures, documentation and graphical symbols.

Industrielle Systeme, Anlagen und Ausrüstungen und Industrieprodukte - Beschriftung von Kabeln / Leitungen und Adern

Systèmes industriels, installations et appareils et produits industriels - Etiquetage des câbles et des conducteurs isolés

La CEI 62491:2008 fournit les règles et lignes directrices d'étiquetage des câbles et des conducteurs isolés/conducteurs utilisés dans les installations, appareils et produits industriels, afin de conserver une relation claire entre la documentation technique et le matériel réel, ainsi qu'à d'autres fins. La Norme internationale CEI 62491 a été établie par le comité d'études 3 de la CEI: Structures d'informations, documentation et symboles graphiques.

Industrijski sistemi, inštalacije, oprema in industrijski izdelki - Označevanje kablov in žil (IEC 62491:2008)

General Information

• Status: Published
• Publication Date: 23-Sep-2008
• ICS: 01.110 - Technical product documentation
• ICS: 29.060.01 - Electrical wires and cables in general
• Technical Committee: EDO - Documentation and graphical symbols
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 15-Sep-2008
• Due Date: 20-Nov-2008
• Completion Date: 24-Sep-2008
• Ref Project: EN 62491:2008 - Industrial systems, installations and equipment and industrial products - Labelling of cables and cores

Relations

• Revised: oSIST prEN IEC 62491:2025 - Industrial systems, installations and equipment and industrial products - Labelling of cables and cores
• Effective Date: 12-Dec-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2008
,QGXVWULMVNLVLVWHPLLQãWDODFLMHRSUHPDLQLQGXVWULMVNLL]GHONL2]QDþHYDQMHNDEORY
LQåLO,(&
Industrial systems, installations and equipment and industrial products - Labelling of
cables and cores (IEC 62491:2008)
Industrielle Systeme, Anlagen und Ausrüstungen und Industrieprodukte - Beschriftung
von Kabeln / Leitungen und Adern (IEC 62491:2008)
Systemes, installations, appareils et produits industriels - Marquage des câbles et des
conducteurs isolés (CEI 62491:2008)
Ta slovenski standard je istoveten z: EN 62491:2008
ICS:
01.110 7HKQLþQDGRNXPHQWDFLMD]D Technical product
L]GHONH documentation
29.060.01 (OHNWULþQHåLFHLQNDEOLQD Electrical wires and cables in
VSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62491
NORME EUROPÉENNE
September 2008
EUROPÄISCHE NORM
ICS 01.110; 29.020.20
English version
Industrial systems, installations and equipment
and industrial products -
Labelling of cables and cores
(IEC 62491:2008)
Systèmes industriels, installations  Industrielle Systeme, Anlagen
et appareils et produits industriels - und Ausrüstungen und Industrieprodukte -
Etiquetage des câbles et Beschriftung von Kabeln / Leitungen
des conducteurs isolés und Adern
(CEI 62491:2008) (IEC 62491:2008)

This European Standard was approved by CENELEC on 2008-07-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62491:2008 E
Foreword
The text of document 3/849/CDV, future edition 1 of IEC 62491, prepared by IEC TC 3, Information
structures, documentation and graphical symbols, was submitted to the IEC-CENELEC parallel vote and
was approved by CENELEC as EN 62491 on 2008-07-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-04-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-07-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62491:2008 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60446 NOTE  Harmonized as EN 60446:2007 (not modified).
__________
- 3 - EN 62491:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

1) 2)
IEC 60445 (mod) - Basic and safety principles for man-machine EN 60445 2007
interface, marking and identification -
Identification of equipment terminals and
conductor terminations
1) 2)
IEC 60757 - Code for designation of colours HD 457 S1 1985

IEC 61082-1 2006 Preparation of documents used in EN 61082-1 2006
electrotechnology -
Part 1: Rules
1) 2)
IEC 61175 - Industrial systems, installations and EN 61175 2005
equipment and industrial products -
Designation of signals
1) 2)
IEC 61666 - Industrial systems, installations and EN 61666 1997
equipment and industrial products -
Identification of terminals within a system

3)
IEC 81346-1 200X Industrial systems, installations and - -
equipment and industrial products -
Structuring principles and reference
designations -
Part 1: Basic rules
1)
ISO/IEC 646 - Information technology - ISO 7-bit coded - -
character set for information interchange

1)
Undated reference.
2)
Valid edition at date of issue.
3)
To be published.
IEC 62491
Edition 1.0 2008-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial systems, installations and equipment and industrial products –
Labelling of cables and cores
Systèmes industriels, installations et appareils et produits industriels –
Etiquetage des câbles et des conducteurs isolés

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 01.110; 29.020.20 ISBN 2-8318-9663-0

– 2 – 62491 © IEC:2008
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Terms and definitions .8
4 Rules.9
4.1 General requirements.9
4.2 Use of designated cable cores.10
4.3 Use of additional labelling .10
5 Identification labelling.11
5.1 General .11
6 Connection labelling .14
6.1 General .14
6.2 Local-end connection labelling .14
6.3 Remote-end connection labelling.15
6.4 Both-end connection labelling.16
7 Signal labelling.17
7.1 General .17
7.2 Labelling by signal designation.17
7.3 Labelling of cables for certain designated conductors.18
8 Composite labelling .19
9 Arrangement of additional labelling.20
9.1 General .20
9.2 Relative positions of the labelling .20
9.3 Characters to be used .20
10 Correspondence between labelling and documentation.21
11 Conformance to this standard.21
Annex A (informative) Examples of labelling .22
Bibliography.30

Figure 1 – Example of identification labelling of a single core cable (W23) and of a
multi-core cable (W24) in which also the different cores are labelled .12
Figure 2 – Example of identification labelling of cores where the initial part of the
reference designation has been partly omitted .13
Figure 3 – Example of local-end connection labelling.14
Figure 4 – Example of remote-end connection labelling for a connection inside a unit.15
Figure 5 – Example of remote-end connection labelling for a cable between different
units .16
Figure 6 – Example of both-end connection labelling .17
Figure 7 – Example of local-end connection labelling combined with signal labelling.19
Figure 8 – Example of composite labelling in which both-end connection labelling is
used together with identification labelling and signal labelling.19
Figure 9 – Examples of arrangements of labelling on cores or cables. .20
Figure A.1 – Circuit diagram used as a basis for the examples .22

62491 © IEC:2008 – 3 –
Figure A.2 – Example of identification labelling .23
Figure A.3 – Example of local-end labelling .24
Figure A.4 – Example of both-end connection labelling .25
Figure A.5 – Example of local end connection labelling with additional information .26
Figure A.6 – Example of signal labelling .27
Figure A.7 – Example of composite labelling.28
Figure A.8 – Example where use is made of the cable colours .29

Table 1 – Example of connection table in which the cable cores are identified by
means of codes for their colour.10
Table 2 – Connection table corresponding to Figure 1 with labelling .12
Table 3 – Connection table corresponding to Figure 2 with labelling .13
Table 4 – Marking of certain designated conductors.18
Table 5 – Methods of labelling defined in this standard .21

– 4 – 62491 © IEC:2008
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL SYSTEMS, INSTALLATIONS
AND EQUIPMENT AND INDUSTRIAL PRODUCTS –
LABELLING OF CABLES AND CORES
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 62491 has been prepared by IEC technical committee 3:
Information structures, documentation and graphical symbols.
The text of this standard is based on the following documents:
CDV Report on voting
3/849/CDV 3/881/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

62491 © IEC:2008 – 5 –
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 62491 © IEC:2008
INTRODUCTION
Additional labelling of cables and cores might be required within larger systems or
installations with many cores of the same colour or with many cables, and where therefore the
use of the designations provided by the cable manufacturer only would be ambiguous.
Due consideration should be given to the fact that additional labelling will cause additional
cost, usually increasing with the number of characters in the labelling string and the number
of different labelling elements. The available space may also impose restrictions with regard
to the number of characters, their height and the length of the labelling. As a general rule the
use of additional labelling should therefore be limited to a necessary minimum and be kept as
short as practicable.
However, also the advantages and benefits should be taken into considerations in choosing
additional labelling of cables and cores.
It is important to notice that a single machine or a system has different needs of information in
the different phases of its lifecycles (assembling, production, service and maintenance).
Additional labelling of cables and cores gives the following advantages:
• the possibilities to communicate and identify signals and connections across different
involved engineering disciplines and departments like:
– process engineering,
– software engineering,
– electrical engineering,
– mechanical/fluid engineering,
– control engineering;
• minimizing the time used to locate an eventual error (and the reason for it) in the test
phase;
• saving time when locating an eventual error (and the reason for it) in the service and
maintenance phase;
• remove the doubt of which core should be connected to which terminal, when replacing
components that are placed close to each other;
• if used in pre-planning, it gives a clear view for panel-builders, electricians/technicians;
service/maintenance and system controllers which will minimize misunderstandings
regarding connections.
Besides being used in connections between terminal blocks, labelling can also be used when
single core cables connect components inside units as: cubicle, pulpit, case, etc.; such
methods make possible:
• a rapid and secure cabling between the terminals of two objects;
• a rapid visual check of cabling, not necessarily looking up in the circuit diagrams;
• a correct and secure change of an object during the maintenance operations of plants.

62491 © IEC:2008 – 7 –
INDUSTRIAL SYSTEMS, INSTALLATIONS
AND EQUIPMENT AND INDUSTRIAL PRODUCTS –
LABELLING OF CABLES AND CORES
1 Scope
This standard provides rules and guidelines for the labelling of cables and cores/conductors
used in industrial installations, equipment and products, in order to maintain a clear relation
between the technical documentation and the actual equipment and for other purposes. The
following methods are described and designated:
• use of coloured cables and designated cores;
• additional identification labelling;
• additional connection labelling; and
• additional signal labelling.
The physical design of the labels, the material to be used for the labels as well as cable
manufacturers’ product bound marking of cables and cores are not part of this standard.
2 Normative references
The following referenced documents are indispensable for the application 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 60445, Basic and safety principles for man-machine interface, marking and identification
– Identification of equipment terminals and conductor terminations
IEC 60757, Code for designation of colours
IEC 61082-1:2006, Preparation of documents used in electrotechnology – Part 1: Rules
IEC 61175, Industrial systems, installations and equipment and industrial products –
Designation of signals
IEC 81346-1, Industrial systems, installations and equipment and industrial products –
Structuring principles and reference designations – Part 1: Basic rules (to be published)
IEC 61666, Industrial systems, installations and equipment and industrial products –
Identification of terminals within a system
ISO/IEC 646, Information technology – ISO 7-bit coded character set for information
interchange
– 8 – 62491 © IEC:2008
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
conductor (of a cable)
part of a cable which has the specific function of carrying current
[IEV 461-01-01]
3.2
cable
assembly of one or more conductors and/or optical fibres, with a protective covering and
possibly filling, insulating and protective material
[IEV 151-12-38]
3.3
core
assembly comprising a conductor with its own insulation (and screens if any)
[IEV 461-04-04]
3.4
terminal
conductive part of a device, electric circuit or electric network, provided for connecting that
device, electric circuit or electric network to one or more external conductors
[IEV 151-12-12, modified]
3.5
terminal block
assembly of terminals in a housing or body of insulating material to facilitate interconnection
between multiple conductors
[IEV 581-06-36]
3.6
terminal designation
identifier of a terminal with respect to the object to which it belongs, related to one aspect of
the object.
[IEC 61666, 3.8]
3.7
signal designation
unambiguous identifier of a signal within a system
[IEC 61175, 3.2]
3.8
reference designation
identifier of a specific object with respect to the system of which the object is a constituent,
based on one or more aspects of that system
3.9
labelling (of a cable or core)
label or labels attached to a cable or core indicating appropriate characteristics

62491 © IEC:2008 – 9 –
3.10
identification labelling
labelling showing the identifier of an object as a constituent of a specific installation, system,
equipment or product
3.11
connection labelling
labelling of a cable or core showing the identifier of the terminal, terminal block or equipment
to which it is connected
3.12
local-end connection labelling
system of labelling of cables and cores where the labelling of the end of the cable or core
refers to the terminal, terminal block or equipment to which it is connected
3.13
remote-end connection labelling
system of labelling of cables and cores where the labelling of the end of the cable or core
refers to the terminal, terminal block or equipment to which the other end of it is connected
3.14
both-end connection labelling
system of labelling of cables and cores where each end of a cable or core is provided with
local-end connection labelling and remote-end connection labelling
3.15
signal labelling
system of labelling of cables and cores used as a supplement to other labelling generally
based on the signal(s) carried by the cable or core
3.16
composite labelling
system of labelling where two or more of the identification labelling, connection labelling and
signal labelling systems are used together
4 Rules
4.1 General requirements
Cables and cores shall be recognizable at each end; it shall be possible to relate cables and
cores to the technical documentation.
This may be carried out by:
• the designation and marking provided by the manufacturer of the cable, see 4.2, or
• an additional labelling, see 4.3.
Additional labelling might be required within larger systems or installations with many cores of
the same colour or with many cables, and where therefore the use only of the designations
provided by the cable or core manufacturer would be ambiguous.
The additional labelling shall be based on one or more of the following:
• the identifier of the cable or core, see Clause 5;
• the connection of the cable or core, see Clause 6, or
• the signal carried by the cable or core, see Clause 7.

– 10 – 62491 © IEC:2008
4.2 Use of designated cable cores
Cable cores are often designated by the manufacturer applying methods such as:
• coloured insulation of the single cores;
• differently coloured (including multi-coloured) insulation of the cores of the cables, or
• differently numbered cores of cables.
These designations should, to the extent possible, be used for the identification of the cores.
Additional labelling is in such cases normally not required.
The use of such designations shall be described in the documentation of the equipment in
accordance with 7.5 and 9.3 of IEC 61082-1.
For the indication of the colours of cable co
...