IEC 60446:2007

IEC 60446 ®
Edition 4.0 2007-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Basic and safety principles for man-machine interface, marking and
identification – Identification of conductors by colours or alphanumerics

Principes fondamentaux et principes de sécurité pour l’interface homme-
machine, le marquage et l’identification – Identification des conducteurs par des
couleurs ou par des repères alphanumériques

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IEC 60446 ®
Edition 4.0 2007-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Basic and safety principles for man-machine interface, marking and

identification – Identification of conductors by colours or alphanumerics

Principes fondamentaux et principes de sécurité pour l’interface homme-

machine, le marquage et l’identification – Identification des conducteurs par des

couleurs ou par des repères alphanumériques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX P
ICS 01.070; 29.020 ISBN 978-2-8322-1322-3

– 2 – IEC 60446:2007 © IEC 2007
CONTENTS
FOREWORD . 3
INTRODUCTION . 5

1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Identification of conductors . 7
5 Identification by colours . 8
5.1 General . 8
5.2 Use of single colours . 8
5.3 Use of bi-colour combinations . 9
6 Identification by alphanumerics . 10
6.1 General . 10
6.2 Identification of certain designated conductors . 11

Annex A (informative) Identification of certain designated conductors by means of
colour code and alphanumeric . 12

Bibliography . 15

Table A.1 – Identification of certain designated conductors by means of colour code
and alphanumeric . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
BASIC AND SAFETY PRINCIPLES FOR MAN-MACHINE
INTERFACE, MARKING AND IDENTIFICATION –

IDENTIFICATION OF CONDUCTORS BY COLOURS OR ALPHANUMERICS

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 60446 has been prepared by IEC technical committee 16: Basic
and safety principles for man-machine interface, marking and identification.
This fourth edition cancels and replaces the third edition, published in 1999 and constitutes a
technical revision. This edition includes the following significant technical changes with
respect to the previous edition:
a) addition of Clause 3 – Terms and definitions
b) addition of Clause 4 – Identification of conductors
c) addition of subclauses 5.3.4 to 5.3.6 – Use of bi-colour combinations
d) addition of subclause 6.2 – Identification of certain designated conductors
e) addition of a new Annex A (informative) “Identification of certain designated conductors by
means of colour code and alphanumeric”
f) deletion of the old Annex A (informative) “Methods of marking PEN conductors in different
countries”.
– 4 – IEC 60446:2007 © IEC 2007
It has the status of a basic safety publication in accordance with IEC Guide 104.
This bilingual version (2014-04) corresponds to the monolingual English version, published in
2007-05.
The text of this standard is based on the following documents:
FDIS Report on voting
16/461/FDIS 16/462/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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.
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.
INTRODUCTION
This International Standard is a basic safety publication is intended for use by technical
committees in the preparation of standards in accordance and with the principles laid down in
IEC Guide 104 and in ISO/IEC Guide 51.
It should be noted that one of the responsibilities of a technical committee is, wherever
possible, to include or refer to requirements of basic safety publications in standards for
equipment within its scope. Consequently, the requirements of this basic safety publication
apply only if they are included, or are referred to in those standards.

– 6 – IEC 60446:2007 © IEC 2007
BASIC AND SAFETY PRINCIPLES FOR MAN-MACHINE
INTERFACE, MARKING AND IDENTIFICATION –

IDENTIFICATION OF CONDUCTORS BY COLOURS OR ALPHANUMERICS

1 Scope
This International Standard provides general rules for the use of certain colours or
alphanumerics to identify conductors with the aim of avoiding ambiguity and ensuring safe
operation. These conductor colours or alphanumerics are intended to be applied in cables or
cores, busbars, electrical equipment and installations.
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 Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE The terms are sorted in alphabetical order.
3.1
functional bonding conductor
conductor provided for functional-equipotential-bonding
[IEV 195-02-16]
3.2
functional earthing conductor
functional grounding conductor (in US)
earthing conductor provided for functional earthing
[IEV 195-02-15]
3.3
line conductor
phase conductor (in AC systems) (deprecated)
pole conductor (in DC systems) (deprecated)
conductor which is energized in normal operation and capable of contributing to the
transmission or distribution of electric energy but which is not a neutral or mid-point conductor
[IEV 195-02-08]
3.4
mid-point conductor
conductor electrically connected to the mid-point and capable of contributing to the
distribution of electric energy

[IEV 195-02-07]
3.5
neutral conductor
conductor electrically connected to the neutral point and capable of contributing to the
distribution of electric energy
[IEV 195-02-06]
3.6
PEL conductor
conductor combining the functions of both a protective earthing conductor and a line
conductor
[IEV 195-02-14]
3.7
PEM conductor
conductor combining the functions of both a protective earthing conductor and a mid-point
conductor
[IEV 195-02-13]
3.8
PEN conductor
conductor combining the functions of both a protective earthing conductor and a neutral
conductor
[IEV 195-02-12]
3.9
protective bonding conductor
equipotential bonding conductor (deprecated)
protective conductor provided for protective-equipotential-bonding
[IEV 195-02-10]
3.10
protective bonding conductor, earthed
protective bonding conductor with a conductive path to earth
3.11
protective bonding conductor, unearthed
protective bonding conductor without a conductive path to earth
3.12
protective conductor
(identification: PE)
conductor provided for purposes of safety, for example protection against electric shock
[IEV 195-02-09]
4 Identification of conductors
Conductors shall be identified either by colours or by an alphanumeric designation or both.
Identification of conductors by colours shall be in accordance with the requirements provided
in Clause 5. Identification of conductors by alphanumerics shall be in accordance with the
requirements provided in Clause 6.

– 8 – IEC 60446:2007 © IEC 2007
5 Identification by colours
5.1 General
For identification of conductors, the following colours are permitted:
– black, brown, red, orange, yellow, green, blue, violet, grey, white, pink, turquoise.
NOTE This list of colours is derived from IEC 60757.
The identification by colour shall be used at terminations and preferably throughout the length
of the conductor either by the colour of the insulation or by colour markers, except for bare
conductors where the colour identification shall be at termination and connection points.
Identification by colour or marking is not required for
– concentric conductors of cables,
– metal sheath or armour of cables when used as a protective conductor,
– bare conductors where permanent identification is not practicable,
– extraneous-conductive-parts used as a protective conductor,
– exposed-conductive-parts used as a protective conductor.
Additional markings, for example alphanumerical, are allowed, provided that the colour
identification remains unambiguous.
5.2 Use of single colours
5.2.1 Permitted colours
The single colours green and yellow are only permitted where confusion with the colouring of
the conductors in accordance with 5.3.2 to 5.3.6 is not likely to occur.
5.2.2 Neutral or mid-point conductors
Where a circuit includes a neutral or mid-point conductor identified by colour, the colour used
for this purpose shall be blue. In order to avoid confusion with other colours it is
recommended to use an unsaturated colour blue, often called "light blue". Blue shall not be
used for identifying any other conductor where confusion is possible.
In the absence of a neutral or mid-point conductor, a conductor identified by blue within the
whole wiring system may also be used for any other purposes, except as a protective
conductor.
If identification by colour is used, bare conductors used as neutral or mid-point conductors
shall be either coloured by a blue stripe, 15 mm to 100 mm wide in each unit or enclosure and
each accessible position, or coloured blue throughout their length.
NOTE 1 IEC 60079-11 prescribes blue when a colour is used for the marking of terminal, terminal boxes, plugs
and sockets of intrinsically-safe circuits.
NOTE 2 In the United States, Canada and Japan, the colour identification white or natural grey for the mid-point
or neutral conductor is used as a replacement for the colour identification blue.
5.2.3 AC-phase conductors
For AC-phase conductors the preferred colours are BLACK, BROWN and GREY.

NOTE 1 In the United States, Canada and Japan, where the colour GREY is used as a replacement for the colour
identification BLUE for neutral or mid-point conductor, the colour GREY shall not be used for identification of phase
conductors if confusion is likely.
NOTE 2 In the United States, Canada and Japan, the colour GREY can be applied as identification of neutral or
mid-point conductor, the colour GREY shall not be used for any other purpose than specified in this standard.
NOTE 3 Neither a phasing nor a direction of rotation is implied by the colours given.
5.3 Use of bi-colour combinations
5.3.1 Permitted colours
Combinations of any two of the colours listed in 5.1 are permitted provided there is no risk of
confusion.
To avoid such confusion the colour green and the colour yellow shall not be used in colour
combinations other than the combination green-and-yellow. The use of the combination of the
colours green-and-yellow is restricted to the purposes of 5.3.2 to 5.3.6.
5.3.2 Protective conductors
Protective conductors shall be identified by the bi-colour combination green-and-yellow.
NOTE 1 It may be necessary to provide additional marking to unambiguously identify a certain designated
conductor.
NOTE 2 An additional colour marking is required for PEN, PEL and PEM conductors.
Green-and-yellow is the only colour combination recognized for identifying the protective
conductor.
The colour combination green-and-yellow shall be such that, on any 15 mm length of the
conductor where colour coding is applied, one of these colours covers at least 30 % and not
more than 70 % of the surface of the conductor, the other colour covering the remainder of
that surface.
If bare conductors, used as protective conductors, are provided with colouring they shall be
coloured green-and-yellow, either throughout the whole length of each conductor or in each
compartment or unit or at each accessible position. If adhesive tape is used, only bi-coloured
tape shall be applied.
NOTE 3 Where the protective conductor can be easily identified by its shape, construction or position, for
example a concentric conductor, colour coding throughout its length is not necessary but the ends or accessible
positions should be clearly identified by the graphical symbol or the bi-colour combination green-and-yellow

or the alphanumeric notation PE.
NOTE 4 In the United States, Canada and Japan the colour identification green for the protective conductor is
used as a replacement for the colour combination green-and-yellow.
NOTE 5 If extraneous conductive parts are used as a PE conductor identification by colours is not necessary.
5.3.3 PEN conductors
PEN conductors, when insulated, shall be marked by one of the following methods:
– green-and-yellow throughout their length with, in addition, blue markings at the
terminations; or
– blue throughout their length with, in addition, green-and-yellow markings at the
terminations.
NOTE 1 The choice of method or methods to be applied within a country should be made by the relevant
committees.
– 10 – IEC 60446:2007 © IEC 2007
NOTE 2 The additional blue markings at the termination may be omitted once either of the following two indents is
met:
– in electrical equipment, if relevant requirements are included in specific product standards or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant committee.
5.3.4 PEL conductors
PEL conductors, when insulated, shall be marked green-and-yellow throughout their length
with, in addition blue markings at their terminations.
NOTE The additional blue markings at the termination may be omitted once either of the following two indents is
met:
– in electrical equipment, if relevant requirements are included in specific product standards or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant committee.
If confusion with a PEN or PEM conductor is likely, the alphanumeric designation as given in
6.2.4 shall be indicated at their terminations.
5.3.5 PEM conductors
PEM conductors, when insulated, shall be marked green-and-yellow throughout their length
with, in addition, blue markings at their terminations.
NOTE The additional blue markings at the termination may be omitted once either of the following two indents is
met:
– in electrical equipment, if relevant requirements are included in specific product standards or within a country;
– in case of wiring systems, for example those used in industry, if decided by the relevant committee.
If confusion with a PEN or PEL conductor is likely, the alphanumeric designation as given in
6.2.5 shall be indicated at their terminations.
5.3.6 Protective bonding conductors
Protective bonding conductors shall be identified by the bi-colour combination green-and-
yellow as specified in 5.3.1.
6 Identification by alphanumerics
6.1 General
The alphanumeric system applies to identification of conductors and of conductors in a group
of conductors. Conductors with green-and-yellow coloured insulation shall only be identified
as a certain designated conductor in accordance with 6.2.2 to 6.2.8.
The identification shall be clearly legible and durable.
NOTE For evaluation of the durability see IEC 60227-2.
All alphanumerics shall be in strong contrast to the colour of the insulation. The identification
shall be given in Arabic numerals.
In order to avoid confusion, unattached numerals 6 and 9 shall be underlined.
The alphanumeric identifications specified in 6.2 shall not be used for any other purpose than
that specified.
6.2 Identification of certain designated conductors
6.2.1 Neutral conductor
The alphanumeric identification of a neutral conductor shall be ‘N’.
6.2.2 Protective conductor
The alphanumeric identification of a protective conductor shall be ‘PE’. This identification also
applies for a protective earthing conductor.
6.2.3 PEN conductor
The alphanumeric identification of a PEN conductor shall be ‘PEN’.
6.2.4 PEL conductor
The alphanumeric identification of a PEL conductor shall be ‘PEL’.
6.2.5 PEM conductor
The alphanumeric identification of a PEM conductor shall be ‘PEM’.
6.2.6 Protective bonding conductor
The alphanumeric identification of a protective bonding conductor shall be ‘PB’.
6.2.7 Protective bonding conductor earthed
If it is necessary to distinguish between a protective bonding conductor earthed and a
protective bonding conductor unearthed, the alphanumeric identification of a protective
bonding conductor earthed shall be ‘PBE’.
6.2.8 Protective bonding conductor unearthed
If it is necessary to distinguish between a protective bonding conductor earthed and a
protective bonding conductor unearthed, the alphanumeric identification of a protective
bonding conductor unearthed shall be ‘PBU’.
6.2.9 Functional earthing conductor
The alphanumeric identification of a functional earthing conductor shall be ‘FE’.
6.2.10 Functional bonding conductor
The alphanumeric identification of a functional bonding conductor shall be ‘FB’.

– 12 – IEC 60446:2007 © IEC 2007
Annex A
(informative)
Identification of certain designated conductors by means
of colour code and alphanumeric

The following table provides a list of designated conductors identified by means of colour
code and alphanumeric.
Table A.1 – Identification of certain designated conductors by means
of colour code and alphanumeric
NOTE Footnotes have been grouped together at the end of Table A.1
Identification of conductors
Colour
Designated terminal
identification
a
Alphanumeric
(For black/white copies,
the colour code according
to IEC 60757 is given)
b
BK
AC conductor terminal
Line 1
L1
or
b
BN
Line 2
L2
or
b
GY
Line 3
L3
c
BU
Mid-point
M
conductor
c
BU
Neutral
N
...