Wire colours according to the NEN-EN-IEC 60204-1 for control cabinets
Colour identification by using common colours is permitted, provided that there is no risk of confusion and no GREEN or YELLOW is used, except in the two-colour combination GREEN-YELLOW.
When using color codes for the identification of current conductors, it is recommended to use the following color codes:
BLACK: AC and DC main power chains;
RED: AC control current chains;
BLUE: DC control current chains; (dark blue)
ORANGE: power chains that do not need to be separated according to 5.3.5. (wires that carry strange voltage and can remain live when the main switch of the cabinet is off. (Usually these are potential-free contacts that go out of the cabinet)
Exceptions to the above are allowed where insulation material is not available in the recommended colours (e.g. in multi-core cables).
Color coding for main power wiring
There are differences in requirements for the coding of cable and conductors. The NEN 1010 prescribes strict color coding. For example, the earth is green/yellow over its entire length, the zero blue and in the case of the three-phase the colors brown/black/gray must be used. This applies to cabling of the installation outside the cabinet.
In the control cabinet/distributor, however, the color coding of the NEN-EN-IEC 61439 applies. And this one is much less stringent. For example, if a ground wire is mounted and the beginning and end of the wire can be seen unambiguously, then for example coding one of the connection points is sufficient. A green-yellow wire is not a mandatory requirement (note: but it is wise in practice). The NEN-EN-IEC 61439 also allows the colour coding of the ends of the wiring and the three-phase wires may all be black.