Core colours and usage

[martin43]

Hi all

Talking to a sparky pal of mine in the pub tonight who has just been on a Select course. It appears that they are pushing the situation that when using 3 core and earth cable, the neutral should use tha grey core and not the black! Black is now considered a phase colour!! I guess the harmonised colours were inevitable eventually, but black for phase seems dead dodgy, especially in installations where old and new colors co-exist?

Just a bit of info for you all to chew over.

Regards
Martin

 

[Spark123]

Yup, red-brown, yellow-black, blue-grey. When using black and grey as phase / neutral / earth conductors they need to be coloured brown / blue / yellow+green as appropriate.
In 3 phase installations it gets worse as blue (old phase) is now neutral and black (old neutral) is now phase, so we now need to mark them up L1,L2,L3,N to try and avoid confusion.

 

[Adam_151]

It makes sense, because before you'd have used red for phase, yellow for cpc and blue for neutral

red became brown, yellow became black and blue became grey

 

[martin43]

Spark123 wrote

When using black and grey as phase / neutral / earth conductors they need to be coloured brown / blue / yellow+green as appropriate.

Fair comment, the point my pal was making is that you couldn't use the black core sleeved blue as a neutral, you had to use the grey core sleeved blue, i.e. there was no choice to be made.

Regards
Martin

 

[Spark123]

I have not yet seen these cast in stone i.e. I don't believe there is anything that actually prohibits you using black (sleeved blue) as neutral and grey (sleeved g/y) as earth, it just seems to be the other way around for the reason given by adam151 that is the adopted method.