Interloper wrote:
"Tim Watts" wrote:
Hang about - whilst I cannot put my finger on the reg this second, I
believe
that using a green/yellow conductor for any other purpose is absolutely
verboten.
You might be right, but I couldn't find a regulation prohibiting the
reassignment of the green/yellow conductor in a multicore cable.
I think you'll find that using the combination green/yellow *COLOUR* for
anything other than a protective conductor is 'absolutely verboten' (or
'absolutely forbidden', once the UK is out of the EU). However,
reassigning the green/yellow conductor of a multicore cable (*NOT* a
single core conductor, which is forbidden), does not appear to contravene
the regs.
Reassignment of a conductor at the termination using tape, sleeving, or
alphanumeric identifiers takes precedence over the original core colour
(although it would be good practice to also oversleeve a reassigned
green/yellow conductor in a multicore cable when alphanumeric identifiers
are being used).
Give me a few hours - I think I can back that up...
OK, over to you, then ;-)
BS7671:2008 17th Edition pre Amendment 1:
514.4.2 (Excerpt):
"The bi-colour combination green-and-yellow shall be used exclusively for
identification of a protective conductor and this combination shall not be
used for any other purpose.
Single-core cables that are coloured green-and-yellow throughout their
length shall only be used as a protective conductor and shall not be over-
marked at their terminations, except as premitted by Regulation 514.4.3..."
Yes, it makes a big point of single-cores but the overall meaning is pretty
clear - it would be a brave man that would argue against that. IMHO the
first sentence covers all eventualities and the second is just
reinforcement.
Reg 514.4.3 refers to PEN conductors which are G/Y with blue sleeves at the
terminations.
But common sense wise - what if someone cuts the cable later, determines
an apparent CPC and bonds it to something exposed?
What, without checking/testing the 'apparent aspect of their CPC
observation? I guess the protective device/mcb/rcd will trip on
re-energisation :-)
If someone 'cuts the cable later', they should be a qualified electrician
and know what they're doing. If they are remaking the termination for some
reason, they should at least notice that the green/yellow conductor has
been
reassigned at the old termination. If they're simply reusing the cable
for something else, then any previous reassignments at the terminations
would be irrelevant.
Yes - but even qualified electricians don't like being caught out with
extreme weirdness ;- This is why there are colour standards - which are
otherwise arguably irrelevent to safety as the electrons don;t really care.
It should now be established that installers may wish to use any single
cable colour, or combination of colours, and overmark at terminations, and
this is not considered a lesser option. For green-and-yellow conductors
in multicore cables, overmarking in another colour at terminations is
permitted. Overmarking at terminations is prohibited for single-core
green-and-yellow conductors."
That's their view, but I don't much like it - I think it is argued on the
letter rather than the spirit of 514.4.2
--
Tim Watts Personal Blog:
http://www.dionic.net/tim/
"History will be kind to me for I intend to write it."