3-core SWA colours

[JohnW2]

When using 3-core SWA for L/N/CPC, is there any convention as to which of black/grey (or yellow/blue in old colours) is used (and appropriately sleeved) for N and which for the CPC? Unless I'm missing it, the regs seem silent on this.

Kind Regards, John

 

[flameport]

Grey = neutral
Black = cpc

 

[JohnW2]

Grey = neutral
Black = cpc

Thanks.

Kind Regards, John.

 

[Spark123]

Don't forget to sleeve them with blue or green/yellow to define their purpose.

 

[JohnW2]

Don't forget to sleeve them with blue or green/yellow to define their purpose.

Thanks. I guess that's what "(and appropriately sleeved)" in my initial message meant

Kind Regards, John.

 

[Spark123]

OOPS, speed reading and all that
You could always just use 2 core that has brown/blue conductors with earth as the armour.
I believe the convention for 3c that most people have adopted is to not use the black as the neutral as to De-Neutralise the association of black with neutrals, iirc it was the idea of the NICEIC.
You are correct that there is no mention of it in BS7671 so if you don't want to listen to the NICEIC then there is nothing stopping you using grey as earth and black as neutral.

 

[JohnW2]

OOPS, speed reading and all that

I'm just pleased to see that it's someone other than me reading too quickly this time!

I believe the convention for 3c that most people have adopted is to not use the black as the neutral as to De-Neutralise the association of black with neutrals, iirc it was the idea of the NICEIC.

That makes sense. What about old colours - one then would have blue and yellow to choose from for neutral. In most senses, blue (sheathed with black) would be the most obvious - but do NICEIC have a view on that?

Kind Regards, John.

 

[ricicle]

It's funny though, the amount of times I see either:-

An old colour 3 core armoured with the yellow taped G/Y for the cpc but no black tape on the blue for neutral

or

Old colour 6243Y (when used as L, SL and N) with the yellow sleeved red for live but no black sleeving/tape on the blue for neutral !

 

[JohnW2]

It's funny though, the amount of times I see either:-
An old colour 3 core armoured with the yellow taped G/Y for the cpc but no black tape on the blue for neutral
or
Old colour 6243Y (when used as L, SL and N) with the yellow sleeved red for live but no black sleeving/tape on the blue for neutral !

I suppose that's understandable, even if wrong. Blue had no particular meaning with old colours, but now identifies neutral, so I guess that those who do as you describe feel that a 'mixed colours' approach is unambiguous.

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.

Kind Regards, John.

 

[ricicle]

... Blue had no particular meaning with old colours...

Err....Phase L3 I think you'll find

 

[JohnW2]

... Blue had no particular meaning with old colours...

Err....Phase L3 I think you'll find

OK - I forget to add "... in a single phase installation"!

Kind Regards, John.

 

[Paul_C]

An old colour 3 core armoured with the yellow taped G/Y for the cpc but no black tape on the blue for neutral

or

Old colour 6243Y (when used as L, SL and N) with the yellow sleeved red for live but no black sleeving/tape on the blue for neutral !

There was actually an exception back under the 13th edition for using blue as neutral in some cases. The main application was for a 3-core flexible cable with phase colors red/white/blue to be used for a single-phase L/N/E connection, with red as L, blue as N, and white sleeved green as E.

 

[JohnW2]

An old colour 3 core armoured with the yellow taped G/Y for the cpc but no black tape on the blue for neutral

I've already indicated why that (lack of sleeving/taping) doesn't surprise me, but what's the answer about the convention when using old-colour 3-core SWA for (1-phase!) L/N+CPC? 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?

Kind Regards, John.

 

[Spark123]

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.

Kind Regards, John.

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

 

[ban-all-sheds]

An old colour 3 core armoured with the yellow taped G/Y for the cpc but no black tape on the blue for neutral

I've already indicated why that (lack of sleeving/taping) doesn't surprise me, but what's the answer about the convention when using old-colour 3-core SWA for (1-phase!) L/N+CPC? 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?

Kind Regards, John.

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.