Electro Technical Council of Ireland

News Archive

New Harmonised European Cable Core Colours

The European harmonised core colour code for multi-core cables are mandatory in new electrical installations certified since 1st April 2006.

Before that date, wiring in new installations, including extensions, could use either the existing colour code or the new harmonised colour code.

The new three- phase core colours are brown, black and grey, with blue for neutral and green/yellow for the earth/protective conductor.

The following limitations apply:

  • Green/yellow cores shall be used only as protective conductors and shall not be converted e.g. by sleeving for use as neutral or line/phase conductors.

  • Blue cores shall be used only as neutral conductors and shall not be converted e.g. by sleeving for use as protective conductors or line/phase conductors.

  • Brown, black or grey cores shall be used only as line/ phase conductors, and shall not be converted e.g. by sleeving for use either as protective conductors or as neutral conductors.

  • Where more than one conductor in a multi-core cable is fed from the same phase, both shall be identified by the relevant phase colour, using sleeving as needed.

  • For single-core cables used for three-phase circuits, the core colours shall be the same as for multi-core cables.

  • Where single-core cables are used to supply single-phase circuits fed from a three-phase distribution board, the respective line/phase conductor colour may be extended to the single-phase circuits fed from that phase.

  • Sleeving or tape used for identification purposes shall be permanent, heat resistant, colour-fast, non-conductive, and shall comply with EN 60454 or other appropriate standard.

  • Four-core cable without a blue core e.g. NYM-J shall be used only for circuits with balanced three-phase loads e.g. three-phase motors.