Using cpc as neutral

[johnduffell]

can you say which Regulation says that doing what you suggest complies with BS7671.

514-03-02 - Every core of a cable shall be identifiable at its terminations and preferably throughout its length.
So brown sleeving at the terminations would comply, although not be preferable
411.3.1.1 - A cpc shall be run to and terminated at each point in wiring and at each accessory
So as long as one cable that has a cpc arrives at the accessory you're ok

 

[Baddegg]

Got to be a wind up,if he’s considering doing it to T&E I can’t imagine he’s used many single core cables ever anyway......

Or multi core cable Either

 

[Octopus]

514-03-02 - Every core of a cable shall be identifiable at its terminations and preferably throughout its length.
So brown sleeving at the terminations would comply, although not be preferable
411.3.1.1 - A cpc shall be run to and terminated at each point in wiring and at each accessory
So as long as one cable that has a cpc arrives at the accessory you're ok

I’ve given you a disagree on the basis that op asks about using the cpc as a live conductor - this could very easily be a single cable arriving at an accessory and therefore will not comply with the regs ....

 

[Andy78]

I think this has drifted quite far from the specific original question of using a cpc in T+E as a live conductor.

 

[johnduffell]

I’ve given you a disagree on the basis that op asks about using the cpc as a live conductor

Fair enough but i feel having stated at least 3 times that it's not acceptable in t&e due to lack of insulation and been very specific about when it isn't an is allowed and for what reason, I'm actually quite disappointed that members i respect on here are throwing around disagrees without explanation beyond that it's shouldn't be allowed.
If you read the op carefully you will note he is trying to learn and he's asking for exactly which reasons it is not allowed, i didn't take away from that that he's planning to do it. Let's try to be constructive and learn something, if the op wants to do something dangerous then that's up to him, we are here to help, right?
Hope that came across ok, I'm not trying to start a disagreement i just think i only learn something from people i disagree with (if they are also happy to discuss)
Happy Monday (just to try to relax the mood

 

[Octopus]

Fair enough but i feel having stated at least 3 times that it's not acceptable in t&e due to lack of insulation and been very specific about when it isn't an is allowed and for what reason, I'm actually quite disappointed that members i respect on here are throwing around disagrees without explanation beyond that it's shouldn't be allowed.
If you read the op carefully you will note he is trying to learn and he's asking for exactly which reasons it is not allowed, i didn't take away from that that he's planning to do it. Let's try to be constructive and learn something, if the op wants to do something dangerous then that's up to him, we are here to help, right?
Hope that came across ok, I'm not trying to start a disagreement i just think i only learn something from people i disagree with (if they are also happy to discuss)
Happy Monday (just to try to relax the mood

Posters need to learn to post better threads and answer questions

For a non spark you seem to be going out of your way to pxss people off.....

 

[johnduffell]

Posters need to learn to post better threads and answer questions

For a non spark you seem to be going out of your way to pass people off.....

Ok fair enough I'm not the thread police so maybe the op broke the rules.
Second i have no desire to annoy people, as that would be pointless. i was purely here to help everyone's knowledge including my own, if you'd rather i leave this thread just let me know and I'll unwatch this thread and let you all to it.

 

[Wilko]

There's no need to have a cpc in every cable, you just need it available at every termination.

Hi - I'm struggling to think of installing a circuit without a cpc. Some have been installed historically, but I don't think that's been since the '60s. As I've started to practice for the regs exam ( ) the two regs I could find that seem relevant are 543.6.1 and 543.2.9 .

 

[KentSparky]

Shouldn't according to what reason though? My point is try to be specific. If this was an eicr you can't just code things because it's not common practice.
In a t&e yes as i said definitely not allowed because of the lack of insulation, however under the regs you can identify the green and yellow insulated conductor in a multi core cable as neutral or line by over sleeving.
Making sweeping statements about how you shouldn't do it isn't really helping anyone to learn something.

Well said

 

[johnduffell]

I'm struggling to think of installing a circuit without a cpc

Thanks for the regs help! I can't think of a circuit without a cpc either, that would certainly not comply and i have not suggested it.

the two regs I could find that seem relevant are 543.6.1 and 543.2.9

"Where overcurrent protective devices are used for fault protection, the protective conductor shall be be incorporated into the same wiring system as the live conductors or in their immediate proximity."
Same wiring system, but not necessarily the same cable, as i understand it.
The latter reg is talking about the special case of rings which are not under discussion but it states that the cpc should also be a ring.

 

[Andy78]

Thanks for the regs help! I can't think of a circuit without a cpc either, that would certainly not comply and i have not suggested it.


"Where overcurrent protective devices are used for fault protection, the protective conductor shall be be incorporated into the same wiring system as the live conductors or in their immediate proximity."
Same wiring system, but not necessarily the same cable, as i understand it.
The latter reg is talking about the special case of rings which are not under discussion but it states that the cpc should also be a ring.

Same wiring system does not necesarilly mean the same cable, but can do, and in the case of the question posed here, a multicore cable was mentioned, which is the wiring system in this case.

Rings are not under discussion, but they might be as the OP gave sparse information. You did bring up quite a few points yourself which were not under discussion.

 

[Richard Burns]

The most relevant regulation for providing a cpc to a circuit that is protected by ADS is probably 411.3.1.1 fourth paragraph: a circuit protective conductor shall be run to and terminated at each point in wiring and at each accessory except a lampholder having no exposed conductive parts and suspended from such a point.

 

[johnduffell]

Same wiring system does not necesarilly mean the same cable,

Agree, that's basically what i meant when i was saying each cable didn't have to have a cpc as long as there was one available at every termination.

You did bring up quite a few points yourself which were not under discussion.

Sorry, i didn't mean to, as far as i can see from rereading my posts every single one was either addressing the question the op originally posted or attempting to clarify information provided by others, together with informative examples for further clarification.

 

[Rpa07]

‘Or Immediate proximity’ I read as 6491 singles in conduit or trunking taking the same complete route as both or all lives. This is in order to terminate at each accessory.

Thanks for the regs help! I can't think of a circuit without a cpc either, that would certainly not comply and i have not suggested it.


"Where overcurrent protective devices are used for fault protection, the protective conductor shall be be incorporated into the same wiring system as the live conductors or in their immediate proximity."
Same wiring system, but not necessarily the same cable, as i understand it.
The latter reg is talking about the special case of rings which are not under discussion but it states that the cpc should also be a ring.

 

[Adam W]

No offence, unfortunately i can't do any more detailed explanation at that point! But i was addressing a part of your post not your usual excellent standards!
I do think that when people are asking this kind of question, we should be precise about why it's not allowed, and appeal to both the regs and to common sense specifically where appropriate.i think a lot of things that are uncommon in domestic are actually within the regs, and sometimes the boundary between what is allowed and what isn't seems to defy common sense, but as long as we discuss properly we will help everyone to learn something new.

There are reasons we work to a standard, primarily for safety.
I don't believe it is helpful for anyone, especially someone who has just begun learning about the subject to routinely challenge the way everything is done seemingly in an attempt to push boundaries and think outside the box.

Unconventional installation methods, or as I call it "doing it weird" is a tell-tale sign of someone who doesn't know what they're doing; the more I've learned about electrics the more I've been able to appreciate that a lot of consideration and knowledge goes into the writing of BS7671 and that deviating from the standard should only be done in exceptional circumstances and not as a norm "because you can".

In this instance the CPC in a T&E is not suitable to use as a neutral because it is not the same size as the other (line) conductors and could overheat, the outer sheath of a T&E is intended for mechanical protection and not electrical insulation; sleeving is intended for identification and not electrical insulation - it is not fixed to the conductor so can easily slide off to reveal a live part where the outer sheath is stripped back or could fall off altogether.

This is basic stuff.

As a minimum it should be enough to say that we don't do it, at a push that regs forbid it, and leave it as that.