IEC 60446 Fundamental and Safety Principles for Marking and Identification of Human-Machine Interface - Identification of Conductors by Colours or Alphanumerics

The standard "IEC 60446 Human-machine interface, fundamental and safety principles for marking and identification - Identification of conductors by colours or alphanumerics" developed by the International Electrotechnical Commission (IEC) describes general rules for the use of specific colours or alphanumerics to identify conductors in order to avoid ambiguity and ensure safe operation. These conductor colours or alphanumerics are intended for application in cables or cores, busbars, electrical equipment and installations.

For the purposes of this standard, the following terms and definitions apply:

• Functional bonding conductor refers to the conductor provided for functional equipotential bonding.
• Functional grounding conductor refers to the grounding conductor provided for functional grounding.
• Line conductor refers to a conductor that is energized in normal operation and can contribute to the transmission or distribution of electrical energy but is not a neutral or midpoint conductor.
• Midpoint conductor refers to the conductor that is electrically connected to the midpoint and can contribute to the distribution of electrical energy.
• Neutral conductor is a conductor that is electrically connected to the neutral point and can contribute to the distribution of electrical energy. expresses
• PEL conductor refers to a conductor that combines the functions of both a protective earthing conductor and a line conductor.
• PEM conductor refers to a conductor that combines the functions of both a protective earth conductor and a midpoint conductor.
• PEN conductor refers to the conductor that combines the functions of both protective earthing conductor and neutral conductor.
• Protective bonding conductor refers to the protective conductor provided for protective equipotential bonding.
• Protective bonding conductor refers to a protective bonding conductor that is grounded and has a conductive path to the ground.
• Protective bonding conductor refers to a protective bonding conductor that is not grounded and does not have a conductive path to ground.
• Protective conductor refers to a conductor provided for safety purposes, for example protection against electric shock.

Conductors are identified by color or alphanumeric designation, or both. Identification of conductors by color shall comply with the requirements specified in this standard. Identification of conductors by alphanumeric designation shall comply with the requirements specified in this standard.

The following colors are allowed for conductor identification: black, brown, red, orange, yellow, green, blue, purple, gray, white, pink, turquoise. This list of colors is based on the IEC 60757 standard.

Colour identification should be used at terminations and preferably along the entire length of the conductor, with the colour of the insulation or colour markers. Colour identification should be at termination and connection points on bare conductors.

Identification by colour or marking is not required for:

• Concentric conductors of cables
• Metal sheath or armour of cables when used as protective conductor
• Bare conductors for which permanent identification is not possible
• Foreign conductive parts used as protective conductors
• Exposed conductive parts used as protective conductors

Additional markings, for example alphanumeric, are permitted provided that the colour designation is not ambiguous.

The single colours green and yellow are only permitted where the probability of confusion is low when the conductors are coloured in accordance with this standard.

If a circuit contains a neutral or center conductor identified by color, the color used for this purpose should be blue. To avoid confusion with other colors, it is recommended to use a desaturated blue color, commonly called light blue. Blue should not be used to identify other conductors where confusion is possible.

If there is no neutral or midpoint conductor, a conductor identified in blue within the entire wiring system can be used for purposes other than the protective conductor.

If colour identification is used, bare conductors used as neutral or midpoint conductors shall be coloured blue along their entire length or with a blue stripe 15 mm to 100 mm wide on each unit or enclosure and at each accessible position.

The IEC 60079-11 standard prescribes blue when a colour is used for marking terminals, terminal boxes, plugs and sockets of intrinsically safe circuits. In the USA, Canada and Japan, the colour designation white or neutral grey is used instead of the colour designation blue as the colour designation for the centre point or neutral conductor.

The preferred colors for AC phase conductors are black, brown and gray.

Any combination of two of the colours listed in this standard is permitted as long as there is no risk of confusion. To avoid such confusion, green and yellow should not be used in colour combinations other than the green-yellow combination. The use of the green-yellow colour combination is limited to the purposes of this standard.

Protective conductors are identified by the two-colour combination green and yellow.

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