Electrical cable. Cutaway end of a two-core and earth electrical cable. This cable has two insulated copper conductors and a bare solid copper earth wire. This type of cable is used in fixed electrical circuits, such as a lighting circuit. These colours (brown is live, and blue is neutral) must be used in new wiring in the UK from April 2006, under regulations that require the same colours to be used all over Europe. The changeover started in April 2004. For the old colours, see T194/604 or T194/613.