Core colours for cables according to NEK TS 606 : 2009

Power and control cables

1-core : Off-white
2-cores: Off-white - Black
3-cores: Off-white - Black - Red
4-cores: Off-white - Black - Red - Blue
5-cores: Off-white - Black - Red - Blue - Black
Above 5-cores : Black numbers on white base.
Separate earth conductor (if any): Yellow/green.

OR

One core: Black
Two cores: Blue – Brown
Two cores + earth Blue – Brown – Yellow/green
Three cores: Brown - Black – Grey
Three cores + earth Brown - Black – Grey – Yellow/green
Four cores: Blue - Brown - Black– Grey
Four cores + earth Blue - Brown - Black– Grey – Yellow/green
Five cores Blue - Brown - Black– Grey - Black
Above 5-cores : Black numbers on white base.

Instrumentation and communications cables

Pair: Black -- Light blue
Triple: Black -- Light blue - Brown

Pairs and triples are identified by numbered tape with printed black numbers or by numbers printed directly on the insulated conductors.

Medium Voltage cables

1-core : Off-white insulation + black semi-conductive layer.
3-cores : Off-white insulation + black semi-conductive

layer identified by White-Black-Red threads under and over the metallic screen on each individual core.
Separate earth conductor (if any): Yellow/green