When did harmonization take place?
You know the answer to that, don't you? In the UK harmonised colours became required for new fixed wiring around 2004, but flex was harmonised a long time before that. ... ore are you asking a more complicated question than that?When did harmonization take place?
Harmonisation has been a gradual process over many decades. Many things are still not harmonised, for example while our T&E now uses harmonised core colors it is still a UK-specific type of cable. Similarly attempts to harmonise plugs and sockets across Europe have met with limited success.When did harmonization take place?
True, and perhaps a little surprisingly, such marking is seemingly acceptable per BS7671, which specifies the acceptable proportions of green and yellow, but does not say that they must 'spiral' around the cable ...I have seen sleeving that appears to have the stripes along the conductor, rather than around it. If you see the yellow side, it could easily be mistaken.
514.4.2 Protective conductor 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. In this combination one of the colours shall cover at least 30 % and at most 70 % of the surface being coloured, while the other colour shall cover the remainder of the surface.
It was certainly at some point during the 70s, but I can't recall precisely when. I was certainly old enough to have become very familiar withy the 'old' flex colours by the time the change occured - and when I heard of the change, I was rather amazed (as remains the case) that anyone would have dreamed of using brown (the colour of earth/soil) for line conductors!AFAIR, flex was harmonised in 1970/1.
All true. However, I thought (maybe wrongly!) that EFLI's question about 'harmonisation' (like all of this thread I had started) related to the core identification colours used in UK fixed-wiring cables.Harmonisation has been a gradual process over many decades. Many things are still not harmonised, for example while our T&E now uses harmonised core colors it is still a UK-specific type of cable. Similarly attempts to harmonise plugs and sockets across Europe have met with limited success.
Not just 3C+E either. In the past I've used SWA and found the 3 cores to be brown, black, grey. IMO, in a purely single phase system, using black for neutral makes just as much sense as using blue in the old colours.
As for that 'somehow', as I've said, I suspect that it was by a process of elimination - since red (which, in any event, was already L) and yellow are almost universally perceived as 'danger' colours.I do take your point that somehow it was decided in some way a non-harmonised blue could be a preferred choice for neutral, but there does appear to be every indication that grey is the new blue.
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