Electrical Wiring Colours - The Old and the New (UK) | EC4U UK electrical wiring colours have changed in the past so it is essential you can tell difference between old wiring colours and new colours. UK Wiring Colours – The Old and the New. The line red and has been replaced by brown. The earth is still identified by green and yellow. Brown Wires (US) | This Old House Black wires, too. But the brown wires threw me. From what I can tell, brown wires are neutral in the UK, whereas in the US neutral is typically white. Now these wires are old--totally ungrounded. Is it just the case that brown wires were used for neutral in the 1940s? (Or maybe my wiring is older. Maybe it was put in while we were still part of Electrical wiring in the United Kingdom - Wikipedia As a result, the international standard blue/brown scheme is as of 2006 found in most appliance flexes. In fixed wiring, the blue/brown scheme is only found in newer (post-2004) installations, and the old IEE red/black scheme is likely to be encountered in existing installations for many more decades.