IEC 60446


The international standard IEC 60446 Basic and safety principles for man-machine interface, marking and identification - Identification of equipment terminals, conductor terminations and conductors was a standard published by the International Electrotechnical Commission that defined basic safety principles for identifying electrical conductors by colours or numerals, for example in electricity distribution wiring. The standard has been withdrawn; the fourth edition was merged in 2010 into the fifth edition of IEC 60445 along with the fourth edition, IEC 60445:2006.

Permitted colours

The standard permits the following colours for identifying conductors:
  • Black Image:Color wire black.svg|50px|Black
  • Brown Image:Color wire brown.svg|50px|Brown
  • Red Image:Color wire red.svg|50px|Red
  • Orange Image:Color wire orange.svg|50px|Orange
  • Yellow Image:Color wire yellow.svg|50px|Yellow
  • Green Image:Color wire green.svg|50px|Green
  • Blue Image:Color wire blue.svg|50px|Blue
  • Violet Image:Color wire violett.svg|50px|Violet
  • Grey Image:Color wire grey.svg|50px|Grey
  • White Image:Color wire white.svg|50px|White
  • Pink Image:Color wire pink.svg|50px|Pink
  • Turquoise Image:Color wire turquoise.svg|50px|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

Neutral or mid-point conductor

If a circuit includes a neutral or midpoint conductor, then it should be identified by a blue Image:Color wire blue.svg|50px|Blue colour. Light blue is the colour used to identify intrinsically safe conductors, and must not be used for any other type of conductor.

AC phase conductors

The preferred colours for AC phase conductors are:
  • L1: Brown Image:Color wire brown.svg|50px|Brown
  • L2: Black Image:Color wire black.svg|50px|Black
  • L3: Grey Image:Color wire grey.svg|50px|Grey
For a single AC phase: brown Image:Color wire brown.svg|50px|Brown

Protective conductor

The colour combination green/yellow Image:Color wire green yellow.svg|50px|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.

Protective earth and neutral (PEN) conductor

Insulated PEN conductors should be marked:
  • either green/yellow Image:Color wire green yellow.svg|50px|Green/Yellow along their entire length with light blue markings at their ends,
  • or light blue Image:Color wire light blue.svg|50px|Light blue along their entire length with green/yellow markings at the ends.
The cable must have a cross sectional area of 16 mm or greater.

United States, Canada and Japan

The three countries United States, Canada and Japan are mentioned in a note in the standard for using different colours:
  • White Image:Color wire white.svg|50px|White or natural grey Image:Color wire gray.svg|50px|Grey for mid-wire or neutral conductor
  • Green Image:Color wire green.svg|50px|Green for the protective conductor

    United Kingdom

British Standard BS 7671:2001 Amendment No 2:2004 adopted the IEC 60446 colours for fixed wiring in the United Kingdom , with the extension that grey Image:Color wire gray.svg|50px|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.

Marking

Where conductors are in addition identified by letters and numbers, then:
Green-and-yellow conductors must not be marked.
Examples: L1, L2, L3, N, L+, L−, M, 35, 1