Joining old colours to new at a junction box

UK fixed-wiring colours changed in 2006. You will constantly meet the OLD colours when extending an older installation: OLD (pre-2006) NEW (2006-on) Red = line → Brown = line Black = neutral → Blue = neutral Green/yellow = earth (unchanged) The conductors do exactly the same job — only the insulation colour changed. When you join an old cable to a new one, you connect by FUNCTION, not by colour: line to line, neutral to neutral, earth to earth. The incoming cable here is old (red/black); the outgoing cable is new (brown/blue). Connect each in turn.