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Why does a 3-phase current named as R,Y,B?

  1. Dec 28, 2011 #1
    Why does a 3-phase current named as R,Y,B??

    A 3-phase current is normally called as R-Red, Y-Yellow, B-Blue,. y is it termed so??? is there any specific reason?? we cant see any colour difference in transmission wires also!
  2. jcsd
  3. Dec 28, 2011 #2


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  4. Dec 28, 2011 #3
    Re: Why does a 3-phase current named as R,Y,B??

    Red Yellow and Blue were the colours of the wires used for the L1, L2 and L3 lives in three phase installations in the UK until 2006. Since then all new installations here have to conform to the EU standard colours Brown, Black and Grey. How this is meant to improve safety is anyone's guess, since there is no requirement (yet) to change old wiring and of course what used to be neutral (black) is now a live colour and what used to be live (blue) is now neutral. Such is life in the committee run insanity that is the European Union.
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