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AMD 2 - changes to conductor colour coding

It seems that AMD 2 is introducing yet another big change to colour coding - albeit only for DC systems. +ve is changing from brown to red and -ve from grey to white.


Also functional earths are changing from Cream to Pink.


Anyone know


a) why the change?

b) why the "old" (i.e. brown/blue) colours aren't permitted as an alternative?


(the 2nd question is about being able to comply with two different versions of BS 7671 at the same time - e.g. where legislation demands compliance with an older version but customer requirements are for compliance with the latest version - DC systems being increasingly common in domestic installations - e.g. PV systems.)


   - Andy.
Parents
  • broadgage:

    Presumably the earthed side of a DC supply is still blue ?


    So two wire DC negative earth would be blue for earthed negative and red for positive.

    And two wire DC positive earth would be blue for the earthed positive and white for negative.

    And three wire DC would be red for positive outer, blue for earthed middle wire, and white for negative outer.


    Blue for positive "just seems wrong" even if it is the earthed side of the supply.

     


    Yes, no change to Blue for mid-point (M) or neutral (N) conductors.

    Blue is only positive in negative-earth situations, and the conductor is identified as "M" not "+".

     



    Not very keen on pink for functional earth either, cream was fairy well established for the minority of installations that needed it.



    The change to pink is already in place since Corrigendum 2018 to BS 7671:2018. In reality, there is no such thing as cream for a cable colour, and hasn't been ever since the cable industry harmonized on what is in effect BS 7645 (IEC 757, implementing CENELEC HD 457 S1). (see my previous post).


    The standard to watch out for identification of cable colours is not BS 7671, but BS EN 60445: in effect, the meaning of wiring colours are stated in that standard, except the assignment of phase rotation (where required) to brown, black and grey - as some of you will be aware, some other EU countries use brown, black and black, with alphanumeric to identify phase rotation if and where needed.

     


Reply
  • broadgage:

    Presumably the earthed side of a DC supply is still blue ?


    So two wire DC negative earth would be blue for earthed negative and red for positive.

    And two wire DC positive earth would be blue for the earthed positive and white for negative.

    And three wire DC would be red for positive outer, blue for earthed middle wire, and white for negative outer.


    Blue for positive "just seems wrong" even if it is the earthed side of the supply.

     


    Yes, no change to Blue for mid-point (M) or neutral (N) conductors.

    Blue is only positive in negative-earth situations, and the conductor is identified as "M" not "+".

     



    Not very keen on pink for functional earth either, cream was fairy well established for the minority of installations that needed it.



    The change to pink is already in place since Corrigendum 2018 to BS 7671:2018. In reality, there is no such thing as cream for a cable colour, and hasn't been ever since the cable industry harmonized on what is in effect BS 7645 (IEC 757, implementing CENELEC HD 457 S1). (see my previous post).


    The standard to watch out for identification of cable colours is not BS 7671, but BS EN 60445: in effect, the meaning of wiring colours are stated in that standard, except the assignment of phase rotation (where required) to brown, black and grey - as some of you will be aware, some other EU countries use brown, black and black, with alphanumeric to identify phase rotation if and where needed.

     


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