E
EddieM
I've looked but have found conflicting answers. When using 3C+E (harmonised) is there a preferred core to use as neutral? Assuming it is suitably sleeved.
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YES. GREY.
There is literature out there that tells you this, there is no literature that suggests black.
It would be worth finding out how they do it in the rest of Europe, this may settle this once and for all.
There is literature out there that tells you this, there is no literature that suggests black.
It would be worth finding out how they do it in the rest of Europe, this may settle this once and for all.
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I think the Nic preferred grey as it distanced the use of black in the old colours, but as long as its sleeved blue does it matter
Given that many places don't allow the reidentification of conductors with sleeving and instead correctly require that they are coloured correctly throughout their length that won't settle anything.
But the correct answer (in BS 7671 terms) is that it needs to be correctly identified at the terminations - there is no correct or incorrect colour to change to another colour.
...and - as you will NEVER be able to assume it has been done a certain way, you will FOR EVER have to make sure so it doesn't matter - despite NIC making up fatuous reasons.
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I have always wondered why triple and earth cable which was not rated for three phase use had colours for three phase use, even when in UK it was Red, Yellow and Blue or in Europe Brown + two blacks. Because when we went to Brown, Black and Grey we were told Red = Brown and Yellow = Black etc. it was considered by many that since Blue was often used as neutral that instead they should use Gray, but there was never anything to say what colour should be used, and with 110 volt it's even worse as we have no neutral just two lines and an earth yet the yellow flex still has a blue core, it should be black or grey, but clearly not blue. Even the yellow plugs and sockets are marked L and N when there is no N.
The electrical engineer often will say which colour to use, so at least on that job there is some standard, but in real terms be it 1,2 and 3 or red yellow and blue having ID for each wire is good, when I worked with European wiring back in the 1980's I found Brown and two blacks hard to work with, same in UK with twin and earth with two reds and an earth. So even if Brown, Black and Grey are not really the right colours for single phase, it's a lot easier to work with than three browns.
Where the problem lies is with maintenance free junction boxes which are not accessible and no one has left any paperwork to say how they are connected. I find writing things down helps, I find working out the logic when written down much easier than working with it in your head.
The electrical engineer often will say which colour to use, so at least on that job there is some standard, but in real terms be it 1,2 and 3 or red yellow and blue having ID for each wire is good, when I worked with European wiring back in the 1980's I found Brown and two blacks hard to work with, same in UK with twin and earth with two reds and an earth. So even if Brown, Black and Grey are not really the right colours for single phase, it's a lot easier to work with than three browns.
Where the problem lies is with maintenance free junction boxes which are not accessible and no one has left any paperwork to say how they are connected. I find writing things down helps, I find working out the logic when written down much easier than working with it in your head.
Good reasons to use grey as the neutral:
1) In the old colours, with red, yellow, blue. Blue WAS the PREFERRED colour to use as neutral. We know that red = brown, yellow = black, blue = grey.
2) In addition to the above, we also recognise the sequence of colours in a flat 3 core+E cable.
Red
Yellow
Bare earth
Blue
Brown
Black
Bare earth
Grey
3) Some people find blue and grey look the same, a common sight problem.
4) The NICEIC like to use grey as neutral in a flat 3 core+E cable.
5) Even before 2004, European fittings such as PIRs used black as a switched live.
Good reasons to use black as the neutral:
There aren't any good reasons.
1) In the old colours, with red, yellow, blue. Blue WAS the PREFERRED colour to use as neutral. We know that red = brown, yellow = black, blue = grey.
2) In addition to the above, we also recognise the sequence of colours in a flat 3 core+E cable.
Red
Yellow
Bare earth
Blue
Brown
Black
Bare earth
Grey
3) Some people find blue and grey look the same, a common sight problem.
4) The NICEIC like to use grey as neutral in a flat 3 core+E cable.
5) Even before 2004, European fittings such as PIRs used black as a switched live.
Good reasons to use black as the neutral:
There aren't any good reasons.
I was thinking the other day, why don't they make the grey core blue, it would save sleeving it some of the time!
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