When did harmonization take place?
Poll: Over-sleeving Harmonised 3C+E Cable
- Thread starter JohnW2
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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?
Kind Regards, John
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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.
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AFAIR, flex was harmonised in 1970/1.
I say AFAIR because I do remember reading a leaflet my Gran had, mentioning the date.
I say AFAIR because I do remember reading a leaflet my Gran had, mentioning the date.
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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.
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 ...
Kind Regards, John
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!
Kind Regards, John
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.
At risk of starting a war ... let's face it, to the best of my knowledge there has as yet been no attempt anywhere in Europe to 'harmonise' even the supply voltage, other than the paper exercise of 'harmonising' the nominal values!
Kind Regards, John
It was about 1970 when harmonised flex became the norm.
Before then, how common was it to use a 3 core+e with one core used as a neutral?
Although timed extractor fans were far from common, electricians were still making invaluable use of 3 core+e cable to achieve L, swL, and N - as they were fitting central heating roomstats, and rewiring houses done in rubber.
I think blue may have been used as neutral as it looks more like black than yellow.
In fact yellow looks a bit like green - and soon enough earth would be green and yellow.
Also, I sometimes see old 3 core flat cable with NO BARE EARTH - the yellow has been used as earth, the blue as neutral. Never the other way round.
(On a side note, with 2 way switching, it seems rare for an electrician to select blue as the common, always red or yellow it seems. Nothing to do with this topic though.)
Before then, how common was it to use a 3 core+e with one core used as a neutral?
Although timed extractor fans were far from common, electricians were still making invaluable use of 3 core+e cable to achieve L, swL, and N - as they were fitting central heating roomstats, and rewiring houses done in rubber.
I think blue may have been used as neutral as it looks more like black than yellow.
In fact yellow looks a bit like green - and soon enough earth would be green and yellow.
Also, I sometimes see old 3 core flat cable with NO BARE EARTH - the yellow has been used as earth, the blue as neutral. Never the other way round.
(On a side note, with 2 way switching, it seems rare for an electrician to select blue as the common, always red or yellow it seems. Nothing to do with this topic though.)
I was, as is frequent, being sarcastic.
If Brown, Black and Grey was introduced in Britain on the pretext of harmonization, then reports of differences in other countries - Austria and Germany today and freqently even the neighbouring Republic of Ireland - seem rather strange for a subject as simple as conductor colours.
If Brown, Black and Grey was introduced in Britain on the pretext of harmonization, then reports of differences in other countries - Austria and Germany today and freqently even the neighbouring Republic of Ireland - seem rather strange for a subject as simple as conductor colours.
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.
Not if one is working on the basis that there should and is an equivalent colour for a harmonised wire to 'match' an old, existing non-harmonised wire.
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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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.
Kind Regards, John
Initially I went for black as neutral, just because black had always been neutral, others seemed to go for grey but it didn't seem to make sense to me.
That was until we did some major work in a plant room where SWA was used for 3ph supplies and we were converting many of the smaller pumps and fans to single phase. Where existing RYB cables had been extended with harmonised it suddenly made sense to use blue/grey for neutral and I've stuck with that since.
Sadly one of the things that got missed at wiring stage, but found during testing, on 2 of the circuits was the yellow/black earth didn't get altered in the local isolator, ie the earth was also isolated along with L&N.
I have also come across this problem elsewhere since.
That was until we did some major work in a plant room where SWA was used for 3ph supplies and we were converting many of the smaller pumps and fans to single phase. Where existing RYB cables had been extended with harmonised it suddenly made sense to use blue/grey for neutral and I've stuck with that since.
Sadly one of the things that got missed at wiring stage, but found during testing, on 2 of the circuits was the yellow/black earth didn't get altered in the local isolator, ie the earth was also isolated along with L&N.
I have also come across this problem elsewhere since.
Well, I guess we got something approaching a consensus. Whilst just over a third of those who voted did not indicate either black or grey as a 'preferred' colour for neutral, of the 17 who did indicate which colour was 'preferred', only 2 said that it was black.
Kind Regards, John
Kind Regards, John
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