On Sun, 27 Jun 2004 11:20:48 +0100, "Andy Wade"
wrote:

"Andy Hall" wrote in message
.. .

Like you say and Andrew had also suggested, large yellow cables seem
sensible.

The correct answer to your original question though is undoubtably (IMHO) to
use two reds (old colours) or browns (new colours). The conductors
concerned are phase conductors of a single-phase AC circuit. Neither is a
neutral because of the earthed centre tap.

This was one of my debates with myself because considering that it is
a centre tapped supply, there are, in effect, two phases albeit not
with the conventional 3 phase 120 degree shift. On the other hand,
the centre tap is not a current carrying conductor, so after thinking
some more I came to the same conclusion as you.

In fact what I've done is to use yellows but to put red markers at
each termination.

I've used numbers as well, but I had been using those as well because
there are becoming quite a large number of wires with all the radial
circuits for outlets and machines being run.


If you use yellow then to comply with BS 7671 all terminations need to be
marked with red (brown if using new colours) sleeving. I agree with you
that the distributed centre tap is a circuit protective conductor, not a
neutral, and therfore should be grn/ylw and not black or blue.

It isn't even as though phase identification is important as it is
with three phase. Nevertheless, I'll probably connect it
consistently.

That's logical but not necessary. But I'd do the same :-)

IMO a better approach, if you're concerned about identifying individual
conductors or circuits in an installation where there's a large number of
wires in one trunking system, is to use the correct BS 7671 colours in
conjunction with wire number markings - for which systems are available from
RS, etc. (as you probably already know) - and to keep relevant
documentation.

Yes, it's all going onto a spreadsheet.



..andy

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