Green and yellow wires not used as earth and missing earths.

[JohnW2]

I would not say unambiguously, Note the full stop. It then continues ...

I don't really see anything ambiguous about that. The first bit you quotes states that G/Y must not be used to identify anything which is not a protective conductor. That makes total sense. The second bit explicitly talks about single-core G/Y cables and says that they must not be used for anything other than as a protective conductor; the fact that they explicitly mention single-core cables clearly indicates that the statement does not apply to multi-core cables.

I don't really see what you could regard as ambiguous about any of that.

.... And it seems to be talking about the use of a green-and-yellow as a PEN conductor ...

I don't really understand what makes you think that. The reg following the one you cite talks about PEN conductors, and requires them to be G/Y+Blue oversleeving at terminations or Blue+G/Y oversleeving at the terminations - which makes good sense.

514.4.3 PEN conductor
A PEN conductor shall, when insulated, be marked by one of the following methods:
(i) Green-and-yellow throughout its length with, in addition, blue markings at the terminations
(ii) Blue throughout its length, with green-and-yellow markings at the terminations.

Kind Regards, John

 

[ericmark]

Sorry I thought you were saying it could be over marked, in fact we seem to agree that is should not be over marked.

 

[JohnW2]

Sorry I thought you were saying it could be over marked, in fact we seem to agree that is should not be over marked.

It is explicit in saying that G/Y singles cannot be used as anything but a 'protective conductor' - so 'cannot be over mnarked' to be used for any other purpose.

The only sort-of exception comes in the following reg, which, as I've shown, says that a G/Y conductor used as a PEN conductor shall also have blue identification at its terminations. However, given that a PEN is partially a 'protective conductor', that's not really inconsistent.

In passing, although my experience is very limited, I can't say that I have ever seen a PEN which uses a G/Y oversleeved with blue or a Blue oversleevd with G/Y. There's no point in looking at my installation, since, as I've illustrated in the past, my incoming neutral (overhead, from a supply which has been PMEd, and hence the neutral could be used as a PEN) is 'identified' by red insulation

Kind Regards, John

 

[EFLImpudence]

G/Y must not be used to identify anything which is not a protective conductor.

How could it - be used to identify anything which is not a protective conductor?

 

[JohnW2]

How could it - be used to identify anything which is not a protective conductor?

I don't really understood the point/question. One obviously "could" use a G/Y-identified conductor as a live conductor, but the regs say that one must not do that (which is reasonable enough).

It's surely no different from saying (explicitly or implicitly) than the colour brown must not be used to 'identify' a protective conductor, isn't it?

Kind Regards, John

 

[EFLImpudence]

It's surely no different from saying (explicitly or implicitly) than the colour brown must not be used to 'identify' a protective conductor, isn't it?

Yes, it is no different but the same question applies.

How could brown be used to identify a protective conductor?

 

[CBW]

How could brown be used to identify a protective conductor?

G/y sleeving?

 

[EFLImpudence]

Yes, but that is not the point being discussed.

"G/Y must not be used to identify anything which is not a protective conductor."

"Brown must not be used to identify anything which is not a line conductor."

How could they?

 

[JohnW2]

Yes, it is no different but the same question applies. How could brown be used to identify a protective conductor?

As I said, although it's obviously literally 'possible' (e.g. per "EFLI's colour coding conventions"), the point is that it's not allowed (and I think BS7671 is merely following international colour-identifier Standards).

Kind Regards, John

 

[EFLImpudence]

Yes, but you are missing the point.

It's like saying the alphanumeric "L" must not be used to identify anything that is not a line conductor.

How can it be? That's what it means.

 

[JohnW2]

Yes, but you are missing the point. It's like saying the alphanumeric "L" must not be used to identify anything that is not a line conductor. How can it be? That's what it means.

I think I understand your point - essentially that it is an unnecessary regulation (with which I agree).

If you are effectively asking why they have singled out G/Y to state that it is a colour which cannot be used other than with its 'designated meaning', then I haven't got a clue. One might speculate that they thought that protective conductors were the most important thing to identify, but I can't really see that it is any less important not to use, say, brown and blue to identify things other than L and N respectively.

However, if we agree to agree that the sentence in question is unnecessary, this is not the main issue being discussed - which is the question of when it is, and is not, permitted to use added identification (such as oversleeving) to use a G/Y-insulated conductor for a purpose other than as a protective conductor - and, as I've said, I think the regs are very clear about that (i.e. allowed in a multi-core cable, but not for a 'single')/

Kind Regards, John

 

[EFLImpudence]

I think I understand your point - essentially that it is an unnecessary regulation (with which I agree).

Yes.

If you are effectively asking why they have singled out G/Y to state that it is a colour which cannot be used other than with its 'designated meaning', then I haven't got a clue.

Ok.

One might speculate that they thought that protective conductors were the most important thing to identify, but I can't really see that it is any less important not to use, say, brown and blue to identify things other than L and N respectively.

Ok.

However, if we agree to agree that the sentence in question is unnecessary, this is not the main issue being discussed - which is the question of when it is, and is not, permitted to use added identification (such as oversleeving) to use a G/Y-insulated conductor for a purpose other than as a protective conductor - and, as I've said, I think the regs are very clear about that (i.e. allowed in a multi-core cable, but not for a 'single')

I agree with that as well.

However, what the regulation states is, in effect, "Do not use G/Y to identify Line or Neutral conductors".

My point is "How can you?" It is not possible.

 

[JohnW2]

However, what the regulation states is, in effect, "Do not use G/Y to identify Line or Neutral conductors". My point is "How can you?" It is not possible.

Not possible whilst adhereing to the regulations/Standards/conventions, no.

However, I think what probably confused me a bit about some of the things you wrote earlier is that you are a person who is usually very keen on the correct distinction between, and use of, "can" and "may" (hence also "cannot" and "may not"). As I said, you "can" ('could') use G/Y to identify L or N but, per regulations etc. you "may not" (more like "must not" or "shall not", in fact).

Kind Regards, John

 

[EFLImpudence]

I meant 'can' as in 'are able to'.

As I said, you "can" ('could') use G/Y to identify L or N but

How? That's not what it means. Not to mention why?

 

[JohnW2]

I meant 'can' as in 'are able to'.

That's what I thought you meant, which is why I was a bit confused (and now am, again!).

If you so wished, it is surely true that you 'can' ('are able to'), literally/physically, use G/Y (or 'sky blue pink', 'polka dot' or anything else) to identify (for yourself) a live conductor - but you 'may not' do that if you want to conform with regulations/conventions etc.

This really does seem to be an unhelpful diversion, since we both know exactly what the situation is, regardless of 'words'.

Kind Regards, John