CPC as live conductor now OK?

[JohnW2]

I think it's probably fair to say that many of us here believe that the regs should require every cable to have a CPC (not the least to reduce risks if a cable is penetrated by a nail, screw or whatever). However, they don't. Provided whatever is at the end of the cable receives a CPC from somewhere, there is no compulsion (in terms of explicit regulations) for every cable to have a CPC.

Hence one ESC-recommended solution to remedy a lighting circuit sans cpc is to run a cpc to every point.

That 'solution' certainly results in compliance with the (explicit) regs - but, as I said, I think there are probably a lot of people who are not happy about the concept of cables without CPCs, pe se (maybe, like BAS, to the extent of regarding it as 'bad workmanship, and therefore non-compliant with 134.1.1). There are, after all, even those who believe that portable Class II devices should be required to have a CPC in their cable. However, as things stand, no explicit regs currently require every cable to have a CPC.

Kind Regards, John

 

[doitall]

I think it's probably fair to say that many of us here believe that the regs should require every cable to have a CPC (not the least to reduce risks if a cable is penetrated by a nail, screw or whatever). However, they don't. Provided whatever is at the end of the cable receives a CPC from somewhere, there is no compulsion (in terms of explicit regulations) for every cable to have a CPC.

As BAS has poined out, whether the absence of a CPC is regarded as 'good workmanship' (hence compliant with 134.1.1 of BS7671) is a different matter. At least some people clearly feel that it's not compliant.

Whatever, this issue becomes moot if (as you were) one is talking about something like a room stat which is supplied with only one cable - in which case even the explicit requirements of the regs effectively require a CPC in that one cable.

Kind Regards, John

My radio hasn't got a cpc, neither has mt printer, scanner or the 4 monitors.

My electric drills haven't got one either, in fact there's loads of stuff haven't got a cpc

 

[RF Lighting]

They're all portable appliances.

 

[JohnW2]

My radio hasn't got a cpc, neither has mt printer, scanner or the 4 monitors. My electric drills haven't got one either, in fact there's loads of stuff haven't got a cpc

Indeed - and I have countless portable Class II appliances without a CPC, too. As I recently wrote, some people think that there should be a requirement for CPS in such cables (arguing that it would be nice if an RCD operated when you chopped through the cable of your hedge trimmer or mower - or picked up and touched a still-live end after you'd chopped it) but, at the present time, there is no such requirement (and most such portable appliances don't cape CPCs in their cables) - any more than there is for cables in fixed wiring.

However, that's all about portable Class II appliances. In this thread we're discussing the requirement to run a CPC to 'every point and accessory' (with the one exception) in fixed wiring.

Kind Regards, John

 

[EFLImpudence]

So -

It has now been decided that g/y insulated conductors forming part of a flexible cable (for the original example buried in masonry and run to a thermostat) can be oversleeved and used as a live conductor with a separate cpc run to the position which would satisfy all relevant regulations.


However, had a past installer done this without installing the separate cpc then in order to satisfy 412.2.3.2 (that a future class 1 thermostat may be required) a separate cpc should be run to the position.
Who, in their right mind, would go to the trouble of doing this now rather than wait until the time when it will actually be required?
Therefore, because something has been wrongly installed it would seem to be acceptable that it be permitted to continue.

I do not agree with the conclusion of these discussions which, it seems to me, has been due to continued brow-beating, twisting and changing the circumstances and concluding that, because it is not specifically forbidden by a regulation, it must therefore be allowed even though, with work being done correctly, it would never arise and so never be necessary nor, indeed, possible.

I maintain that the original example of requiring the cpc to be used as a live conductor (for a thermostat) is not a valid reason as there are several ways that this problem could be avoided and doing so is tantamount to intentionally making something non-compliant.

 

[JohnW2]

It has now been decided that g/y insulated conductors forming part of a flexible cable (for the original example buried in masonry and run to a thermostat) can be oversleeved and used as a live conductor with a separate cpc run to the position which would satisfy all relevant regulations.

Indeed (even if a lot of us don't like it) - although I would question the "now" - we 'decided' this back in early January. However, I'm a bit confused by what you go on to say, because, at first sight, you appear to be making contradictory statements. Firstly you say:

However, had a past installer done this without installing the separate cpc then in order to satisfy 412.2.3.2 (that a future class 1 thermostat may be required) a separate cpc should be run to the position. Who, in their right mind, would go to the trouble of doing this now rather than wait until the time when it will actually be required? Therefore, because something has been wrongly installed it would seem to be acceptable that it be permitted to continue.

That is the pragmatic view which is being promoted by doitall (even he has said that he wouldn't oversleeve a G/Y in a new install). Not only pragmatic, but also more-or-less common sense. However, none of this discussion has really been about common sense but, rather, the matter of regulations - and taking this pragmatic approach would leave the installation non-compliant with the regs. Doitall's approach all along has been to try to 'prove' that it is acceptable in terms of the regulations, which (in the absence of a CPC from somewhere else), I can't see that it is. Anyway, having seemingly given blessing to that pragmatic approach, you then go on to say:

I do not agree with the conclusion of these discussions which, it seems to me, has been due to continued brow-beating, twisting and changing the circumstances and concluding that, because it is not specifically forbidden by a regulation, it must therefore be allowed even though, with work being done correctly, it would never arise and so never be necessary nor, indeed, possible.

I think I must be being dim, because I can't really see how your disagreement with this fits with what you've written above.

...or are you, perhaps, merely agreeing that the practice is not 'allowed' (compliant with regs) but are expressing the view that, nevertheless, you feel that no-one in their right mind would bother about complying with the regs in terms of the issue we're talking about?

Kind Regards, John

 

[EFLImpudence]

My disagreement is with the acceptance that the cpc is allowed to be used as a live conductor.

I think I must be being dim, because I can't really see how your disagreement with this fits with what you've written above.

Pragmatism.

That is - what people will do.
I can't imagine anyone chasing a wall to install a cpc which is not needed just in case it is needed in the future.

...or are you, perhaps, merely agreeing that the practice is not 'allowed' (compliant with regs) but are expressing the view that, nevertheless, you feel that no-one in their right mind would bother about complying with the regs in terms of the issue we're talking about?

Well, plumbers don't.

I will hazard a guess that the customer won't.
An explanation would, without doubt, be greeted with derision.

That's why I wrote that, because it has been installed incorrectly it will be allowed to continue and
that it has been done wrongly on purpose because it should not have been done as it is not necessary.

Through the many pages of argument has anyone suggested that a replacement thermostat be fitted?
Why was it necessary to fit an unsuitable thermostat?

 

[JohnW2]

I think I must be being dim, because I can't really see how your disagreement with this fits with what you've written above.

Pragmatism. That is - what people will do. I can't imagine anyone chasing a wall to install a cpc which is not needed just in case it is needed in the future.

Fair enough - I certainly can't argue with that and, although this is hardly relevant, it's undoubtedly the approach I would take if I encountered the issue in my own home. However, how would this work if an electrician did it? Aren't scheme-registered electricians constrained to work in compliance with BS7671? Could you issue, say, a minor works certificate if it what you'd ended up with was not BS7671-compliant?

Through the many pages of argument has anyone suggested that a replacement thermostat be fitted?
Why was it necessary to fit an unsuitable thermostat?

I can't be bothered to hunt for it, but I'm all but certain that very early on (in this thread and/or the original one), it was suggested that a 2-wire thermostat should be used, thereby making the problem go away. However, the obsession with proving that the 'G/Y sleeving' practice was 'allowed'developed a life of it's own, and I don't even think there was any significant discussion about the possibility of using a 'suitable' thermostat!

Kind Regards, John

 

[EFLImpudence]

However, how would this work if an electrician did it? Aren't scheme-registered electricians constrained to work in compliance with BS7671? Could you issue, say, a minor works certificate if it what you'd ended up with was not BS7671-compliant?

I wouldn't do it.

However, the obsession with proving that the 'G/Y sleeving' practice was 'allowed'developed a life of it's own,

It did.

I disagree with the outcome.

 

[JohnW2]

However, how would this work if an electrician did it? Aren't scheme-registered electricians constrained to work in compliance with BS7671? Could you issue, say, a minor works certificate if it what you'd ended up with was not BS7671-compliant?

I wouldn't do it.

Ah, I see. Does that mean that you would also hope that other electricians wouldn't do it? If so, does that mean that your comments about pragmatism solely related to your (undoubtedly largely true) beliefs about what plumbers and DIYers would do?

However, the obsession with proving that the 'G/Y sleeving' practice was 'allowed'developed a life of it's own,

It did. I disagree with the outcome.

Like many others, I would dearly like to be able to disagree with the outcome, but I find it hard to do so in terms of the word of the regs. I realise that you said that you don't believe that something is necessarily 'allowed' just because the regs don't say that it's not allowed, but I'm not quite sure how that works. You surely don't take the view that nothing is allowed unless there is a regulation specifically and explicitly saying that it is allowed, do you? (I imagine that would require a million-page set of regs, and still would not be exhaustive!). If you believe that the practice is non-compliant with the regs, it would not be unreasonable for someone to ask you to indicate what regulation you believe it violates - what would be your answer? 134.1.1?

Kind Regards, John

 

[Norcon]

Whats wrong with this picture? Real purdy innit.

 

[EFLImpudence]

Ah, I see. Does that mean that you would also hope that other electricians wouldn't do it?

Well, obviously.

Can you give an example of when it would really be necessary?

If so, does that mean that your comments about pragmatism solely related to your (undoubtedly largely true) beliefs about what plumbers and DIYers would do?

I suppose so and if discovering it had been done the remedy may be difficult but the only conclusion would be that it had been done wrongly.

Like many others, I would dearly like to be able to disagree with the outcome, but I find it hard to do so in terms of the word of the regs. I realise that you said that you don't believe that something is necessarily 'allowed' just because the regs don't say that it's not allowed, but I'm not quite sure how that works.

That's understandable but something that is unnecessary may not have been actually banned.
Why is three-core flex so coloured?
Does 514.4.3 mean the cpc can only be used as a switched live?

You surely don't take the view that nothing is allowed unless there is a regulation specifically and explicitly saying that it is allowed, do you?

The result of both would be what? Common sense.

(I imagine that would require a million-page set of regs, and still would not be exhaustive!). If you believe that the practice is non-compliant with the regs, it would not be unreasonable for someone to ask you to indicate what regulation you believe it violates - what would be your answer? 134.1.1?

I do but I realise I may be on shaky ground if there is no actual definition of good workmanship and others have differing views.
However, doing what seems just wrong cannot be good workmanship to me, can it?


I shall reiterate that my main objection is that the work, necessitating using the cpc as a live conductor, has been wrongly done in the first, or second, place.
Therefore it is bad practice and so poor workmanship.

 

[Iggifer]

Whats wrong with this picture? Real purdy innit.

that cpc isnt even oversleeved, and no grommets, and it's generally rough

 

[JohnW2]

Ah, I see. Does that mean that you would also hope that other electricians wouldn't do it?

Well, obviously. Can you give an example of when it would really be necessary?

"Necessary" in the sense of there being no alternative? If so, then I obviously cannot give an example.

Like many others, I would dearly like to be able to disagree with the outcome, but I find it hard to do so in terms of the word of the regs. I realise that you said that you don't believe that something is necessarily 'allowed' just because the regs don't say that it's not allowed, but I'm not quite sure how that works.

That's understandable but something that is unnecessary may not have been actually banned.

Of course not. Indeed, a vast number of things which are 'unnecessary' are harmless and/or reasonable, even if 'not necessary', so there's no reason why they should be banned. However, you seem to be implying that 'unnecessary' implies 'wrong', or even non-compliant - and that surely will very often not be the case?

Does 514.4.3 mean the cpc can only be used as a switched live?

I think there's a typo in there somewhere. 514.4.3 is about PEN conductor identification.

If you believe that the practice is non-compliant with the regs, it would not be unreasonable for someone to ask you to indicate what regulation you believe it violates - what would be your answer? 134.1.1?

I do but I realise I may be on shaky ground if there is no actual definition of good workmanship and others have differing views. However, doing what seems just wrong cannot be good workmanship to me, can it?

Indeed. As I wrote yesterday, this is what I call 'professionalism'. However, many will regard it as unsatisfactory to have compliance (or non-compliance) with regulations dependent upon (inevitably varying) individual subjective opinions - and I have some sympathy with that viewpoint.

In terms of the specific, it would be so easy for the regs to explicity ban the use of a G/Y insulated cores as anything other than earth/CPC (even if oversleeved at it ends) - which is, I imagine,what most of us would like to see. Reliance on the subjective 134.1.1 would not then be needed.

I shall reiterate that my main objection is that the work, necessitating using the cpc as a live conductor, has been wrongly done in the first, or second, place. Therefore it is bad practice and so poor workmanship.

In terms of current regs/thinking, I cannot really disagree with that. I don't know the detailed history of the regs in relation to this matter but there was presumably a time when the requirement for a CPC at each point/accessory did not exist, otherwise all the lighting circuits without CPCs would have been non-compliant. On that assumption, what would you say if the thermostat cable had been installed under such past regs - would you still say that it had "been wrongly done in the first place", and how would you then feel about allowing the situation to persist?

Kind Regards, John

 

[EFLImpudence]

I think there's a typo in there somewhere. 514.4.3 is about PEN conductor identification.

No typo, a green and yellow conductor oversleeved with blue is the identification for a pen conductor so presumably cannot be used for a cpc used as a neutral (should a plumber wish).

I don't know the detailed history of the regs in relation to this matter but there was presumably a time when the requirement for a CPC at each point/accessory did not exist, otherwise all the lighting circuits without CPCs would have been non-compliant. On that assumption, what would you say if the thermostat cable had been installed under such past regs - ",would you still say that it had "been wrongly done in the first place and how would you then feel about allowing the situation to persist?

Yes, because there is a simple solution - fit a suitable thermostat.

As for the lighting circuit, I believe we recommend, no insist on, the fitting of only suitable accessories or rewiring.