Wiring Colours | Electrical Cable Colour Coding Standards Fixed wiring electricity supply requires specific wiring colour regulations (bs 7671) to identify different power lines in different countries. The USA have their own wiring colours for electrical circuits, black, red, and blue are used for 208 VAC three-phase; brown, orange and yellow are used for 480 VAC. Wiring a Light Fitting | Guide for How to Fit a Light Warning: To complete electrical works you must comply with Electrical Regulations – Click here for more information. Please also see our project on the New Wiring and Cable Colours. The first rule here is, when wiring a light fitting or chaging a light fitting, if you are in any doubt whatsoever, get an electrician – Electricity kills. Please remember when attempting any electrical House Wiring for Beginners - DIYWiki All cable colours are as expected except for the switched live. Light switches are usually wired with standard T&E, which means the switched live wire will be black (existing installs) or blue (new installs) - this should be marked with live coloured tape or sleeving (though alas this is often missing).