Hi Phil. You wrote: <We make an instrument that is powered from a three phase supply. The instrument power is supplied down a flexible conduit with individual wires which the customer wires into (his) wall mounted isolator. The colours used are red-blue-yellow for the phases, black for neutral and green/yellow for earth. I have been told that it is a European-wide requirement that the colours should be brown for all phases, blue for neutral and green/yellow for earth.
Can anyone confirm this and perhaps point me to the appropriate regulations.> Basically, in the UK three phase distribution in a building is Red/ Blue/Yellow (IEE Regs) Three phase inside a Control System for a Machine (BSEN60204) is Black, and single phase live wire is Brown. Neutrals are all blue, but under BSEN60204 so is D.C. power, so you need Dark Blue, and Light Blue sometimes. The cable that connects from the wall distribution to the Control main isolator is in a bit of a grey area, my own attitude is that the RBY stops at the wall socket/terminal box (6491X cable), and Black starts at the free plug/tails (BS6231 or Tri-rated cable). That might help a bit. Chris Dupres Smallfield, Surrey
