3-core SWA colours

[Paul_C]

Is it, as per what you've written above - blue for neutral (with black sleeve!) and yellow (with G/Y sleeve) for CPC - or is it yellow for neutral (with black sleeve), maybe because of fears about black/blue confusion?

I don't think I've ever seen red/yellow/blue SWA in such an application used any other way than blue (sleeved black) for N and yellow (sleeved green or green/yellow) for E. It was almost certainly the natural application when yellow replaced white, since blue already had the exemption for neutral under the 13th edition, and soon after green/yellow started to appear as an alternative to green for earth, so the yellow core was seen as being "halfway there" already. And it was the replacement for white, which was also sleeved green for earth under the 13th edition.

 

[JohnW2]

I suspect it used to be:
Red for live, because that's standard.
Blue for neutral, because that's what N is in flex, so people should be expecting it, so no need to bother with black sleeving.
Yellow for cpc because that's half way there already.

Thanks. Yes. that would be the most logical / common sense approach - although I imagine that regs would expect black sleeving of blue, even though it' theoretically redundant.

As you will be aware from the thread, the only reason why I wondered whether it might be the opposite of that is because of the avoidance of using black for neutral with harmonsied colours, but I suppose that's a bit different.

Kind Regards, John.

 

[JohnW2]

I don't think I've ever seen red/yellow/blue SWA in such an application used any other way than blue (sleeved black) for N and yellow (sleeved green or green/yellow) for E. It was almost certainly the natural application when yellow replaced white, since blue already had the exemption for neutral under the 13th edition, and soon after green/yellow started to appear as an alternative to green for earth, so the yellow core was seen as being "halfway there" already. And it was the replacement for white, which was also sleeved green for earth under the 13th edition.

Thanks. Yes, that all makes sense.

Kind Regards, John.

 

[JohnW2]

Something I've seen done a few times, but I suspect that you folks must see all the time, is old-colour-insulated conductors sheathed with harmonised colours - e.g. brown sleeving on the black-insulated conductor in T/E to a light switch. Again, it's theoretically not ambiguous (although wrong), this time because brown had no specific meaning in old colours.

Have come across it yes, not imo a problem as long as the red is also sleeved brown

Yes, that is certainly clear and unambiguous. I think when I've seen it, the red has usually NOT been sleeved with brown (reflecting the situation had they sheathed the black with red). Although again undoubtedly wrong ('doubly wrong', this time!), it is still not really be ambiguous (in a 1-phase system).

Kind Regards, John.