Old vs New Cable Colours

In 2006 the UK adopted the harmonised European colour code for fixed wiring. If your home was wired before 2006, you'll find the old colours. Both systems are still in active use.

Colour Comparison

Pre-2006 (old)Post-2006 (new)LiveRedBrownNeutralBlackBlueEarthGrn/YelGrn/Yel

Mixing Old and New

When extending an old circuit, you must sleeve any old-colour conductors where they connect to new wiring. Specifically:

  • Sleeve red with brown (or mark it L)
  • Sleeve black with blue (or mark it N)

A label reading "Caution: this installation has wiring to two colour standards" must be placed at the consumer unit.

Switch Returns

In both systems, a cable used as a switch return (a neutral core repurposed as live) must be sleeved brown at both ends to indicate it is live when the switch is on.

Important: Black-sleeved or unsleeved return conductors are a common find in old installations. They are potentially dangerous — always check with a non-contact tester before touching any black conductor.