14.2 Identification of conductors
14.2.1 General requirements
Conductors shall be identifiable at each termination in accordance with the technical
documentation (see clause 18). Annex B question 31 may be used for agreement between
supplier and user regarding a preferred method of identification.
Where colour-coding is used for identification of conductors, the following colours may be
used:
BLACK, BROWN, RED, ORANGE, YELLOW, GREEN, BLUE (including LIGHT BLUE), VIOLET,
GREY, WHITE, PINK, TURQUOISE.
NOTE This list of colours is derived from IEC 60757.
It is recommended that, where colour is used for identification, the colour be used throughout
the length of the conductor either by the colour of the insulation or by colour markers. An
acceptable alternative may consist of additional identification at selected locations.
For safety reasons, the colour GREEN or the colour YELLOW should not be used where there
is a possibility of confusion with the bicolour combination GREEN-AND-YELLOW (see 14.2.2).
Colour identification using combinations of those colours listed above may be used provided
there can be no confusion and that GREEN or YELLOW is not used except in the bicolour
combination GREEN-AND-YELLOW.
14.2.2 Identification of the protective conductor
The protective conductor shall be readily distinguishable by shape, location, marking, or colour.
When identification is by colour alone, the bicolour combination GREEN-AND-YELLOW shall
be used throughout the length of the conductor. This colour identification is strictly reserved for
the protective conductor.
For insulated conductors, the bicolour combination GREEN-AND-YELLOW shall be such that
on any 15 mm length one of the colours covers at least 30 % and not more than 70 % of the
surface of the conductor, the other colour covering the remainder of the surface.
Where the protective conductor can be easily identified by its shape, position, or construction
(e.g. a braided conductor), or where the insulated conductor is not readily accessible, colour
coding throughout its length is not necessary but the ends or accessible positions shall be
clearly identified by the graphical symbol 417-IEC-5019 or by the bicolour combination GREENAND-
YELLOW.
14.2.3 Identification of the neutral conductor
Where a circuit includes a neutral conductor identified by colour, the colour shall be LIGHT
BLUE (see 3.1.2 of IEC 60446). LIGHT BLUE shall not be used for identifying any other
conductor where confusion is possible.
Where identification by colour is used, bare conductors used as neutral conductors shall be
either coloured by a LIGHT BLUE stripe, 15 mm to 100 mm wide in each compartment or unit
or at each accessible position, or coloured LIGHT BLUE throughout their length.
14.2.4 Identification of other conductors
Identification of other conductors shall be by colour (either solid or with one or more stripes),
number, alphanumeric, or a combination of colour and numbers or alphanumeric. When
numbers are used, they shall be Arabic; letters shall be Roman (either upper or lower case).
It is recommended that insulated conductors be colour-coded as follows:
– BLACK: a.c. and d.c. power circuits;
– RED: a.c. control circuits;
– BLUE: d.c. control circuits;
– ORANGE: interlock control circuits supplied from an external power source.
Exceptions: to the above are permitted where:
– individual devices are purchased complete with internal wiring;
– insulation is used that is not available in the colours required; or
– multiconductor cable is used, but not the bicolour combination GREEN-AND-YELLOW.
