On Wed, 18 Jun 2008 07:46:48 +0100 someone who may be Tony Dragon
 wrote this:-

>> I made a mistake about three phase colours, umm mea culpa. I plead the
>> fact that no bugger can remember the current scheme which is just plain
>> silly.
>
>On your last point, I agree, why fix it if it ain't broke?

<http://www.theiet.org/publishing/wiring-regulations/colour/>

"Q2. Why are the changes for conductor colour identification
necessary?

"A2 - The United Kingdom agreed some 28 years ago to adopt the
colour blue for neutral conductors, and has since used harmonized
(brown/blue/green-and-yellow) colours for the identification of the
cores of flexible cables and flexible cords but, at that time, no
move was made towards such harmonisation for non-flexible cables
used for fixed wiring. Unfortunately, whilst the United Kingdom was
contemplating such change, much of the rest of Europe was
standardising on blue for neutral, with brown and/or black phases.

"When it became evident in 1999 that, within a few years, a new
European Standard would require the use of the colour blue (rather
than black) for the neutral conductor of fixed wiring throughout
Europe, it became necessary for the United Kingdom to address the
cable colour issue with some urgency.

"The joint BSI/Institution of Engineering and Technology committee
now responsible for the technical content of the Wiring Regulations
(BS 7671) established a Working Group to consider the position the
United Kingdom should take with respect to the harmonisation of the
colours of the conductors of non-flexible cables for fixed wiring.

"The Working Group concluded that the United Kingdom had no
realistic option but to agree to use the colour blue for the
neutral, and brown for the phase conductor of single-phase circuits.

"It also concluded that, due to the widespread adoption in the rest
of Europe, the United Kingdom would have to accept black for one of
the other phases of a multi-phase circuit. The Working Group also
considered that there was a need to be able to distinguish between
the phases of a three-phase circuit and decided to propose the
colour grey for one of the phases, because, of the very few
remaining pan-European colour options, this seemed to have the least
disadvantages.

"The Working Group’s recommendations subsequently formed the basis
of a United Kingdom proposal which was accepted by the CENELEC
countries almost unanimously. Europe now has the opportunity to
fully harmonise the colour identification system not only for
non-flexible cables for fixed wiring, but also for flexible cables
and cords and distribution cables."




-- 
  David Hansen, Edinburgh 
 I will *always* explain revoked encryption keys, unless RIP prevents me
 http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54