IEC 60446

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International standard IEC 60445 (Formerly IEC 60446) defines basic safety principles for identifying electrical conductors by colours or numerals, for example in electricity distribution wiring.

Permitted colours[edit]

The standard permits the following colours for identifying conductors:

black, brown, red, orange, yellow, green, blue, violet, grey, white, pink, turquoise

(The colours green and yellow on their own are only permitted where confusion with the colouring of the green/yellow protective conductor is unlikely. Combinations of the above colours are permitted, but green and yellow should not be used in any of these combinations other than as green/yellow for the protective conductor.)

Use of colours[edit]

Neutral or mid-point conductor[edit]

If a circuit includes a neutral or mid-point conductor, then it should be identified by a Color wire light blue.svg blue colour (preferably light blue). Light blue must not be used for any other type of conductor.

AC phase conductors[edit]

The preferred colours for AC phase conductors are Color wire black.svg black, Color wire brown.svg brown and Color wire grey.svg grey

Protective conductor[edit]

The colour combination Color wire green yellow.svg green/yellow is always and exclusively used to identify the protective conductor. On any 15 mm length of the conductor, one of these two colours should cover between 30% and 70% of the area and the other the remaining area.

PEN conductor[edit]

Insulated PEN conductors (a single wire that serves as combined Neutral and Earth) should be marked either Color wire green yellow.svg green/yellow along their entire length with light blue markings at their ends, or light blue along their entire length with green/yellow markings at the ends. The cable must have a cross section of 16 mm2 (5 AWG) or greater.

United States, Canada and Japan[edit]

The three countries United States, Canada and Japan are mentioned in a note in the standard for using different colours:

  • Color wire white.svg white or Color wire grey.svg natural grey for mid-wire or neutral conductor (instead of Color wire light blue.svg light blue)
  • Color wire green.svg green for the protective conductor (instead of Color wire green yellow.svg green-and-yellow)

United Kingdom[edit]

British Standard BS 7671:2001 Amendment No 2:2004 adopted the IEC 60446 colours for fixed wiring in the United Kingdom [1], with the extension that Color wire grey.svg grey can also be used for line conductors, such that three colours are available for three-phase installations. This extension is expected to be adopted across Europe and may even find its way into a future revision of IEC 60446.


Where conductors are in addition identified by numbers, then these numbers must be written in Alpha numerals, digits 6 and 9 must be underlined, and green-and-yellow conductors must not be numbered.