Using CPC as live conductor.... ok i know, but...

[uksparks]

Hi,

Had to change a bathroom fan at the weekend for someone and they wanted it to be on a timer, but couldnt as the cable was buried in the wall and wouldn't move etc..

the cable that fed it was a three core flex, I the earth was not being used anyway due to the load on the end etc.

I know you are not meant to use the CPC as a live conductor, but if its flex and the same CSA and you were to correctly identify it with brown etc, would it have then been acceptable?

I didn't do it, but it made me think, oh i so could have used it, but it just seemed wrong. I can understand why you wouldn't do it in twin and earth, but surely where its flex or all conductors are the same CSA and have their own sheathing on them inside the outer, would it have been acceptable or not?

I am going to say not on the basis CPC is CPC and nothing else, any thoughts would been welcomed.

 

[Silly Sausage]

Must a typo - I think they mean 514.4.2. Daz

- - - Updated - - -

The diagram doesn't show a PEN conductor.

Pretty sheite publication if they can't trap errors like that.
What rag was it anyway?

 

[SPARTYKUS]

i would have had no problem using that flex , brown sleeving on both ends whats the problem , common sense over rules the the regs sometimes , tin hat firmly on

Problem is when, as mentioned, someone taps into a cable, sees green & yeller, assumes its a cpc.....etc

 

[uksparks]

as long as the fan was classII and there was no alternative, i might be tempted.

Yes Class II, tempting isn't it. i didn't though as I felt it was just wrong. The problem was the flex was buried in the wall and I really wanted to swap it for a bit of three core, but though hmmm I could use that CPC as its not being used... It was a conductor like the others, so its not like it didnt have any insulation or a smaller CSA.

 

[MDJ]

It doesn't. If it's over sleeved at the end than its ok.

Unless it's a single core cable which can not be sleeved over.


But as darkwood says it's not good practice...

Thats not the way I read the reg, it says green and yellow cables throughout their length shall only be used as a protective conductor, the oversleeve bit is when you mark the ends with a blue indication for PEN conductors.

 

[uksparks]

yep fair enough, i cant find the article link but found this on a forum page......

View attachment 23390

This is exactly what I was looking at.

 

[uksparks]

Problem is when, as mentioned, someone taps into a cable, sees green & yeller, assumes its a cpc.....etc

That's where I was going with it, I know If I cut into a cable and i saw a green / yellow, I probably wouldn't give it any thought and think, yep that's the earth. I think its a good idea to use a CPC as a CPC only and nothing else.

 

[uksparks]

I think if you start using whats really seen to be an earth throughout its length as a live conductor, you are kind of cutting corners in a way and your standards (if you have any) will probably start going down hill, personally I would rather do the right thing and tell the customer, that's going to cost you, you need a new bit of cable.

 

[DPG]

The two regs in question are here, in case anyone hasn't got the regs with them:

514.4.2 Protective conductor

The bi-colour combination green-and-yellow shall be used exclusively for identification of a protective conductor

and this combination shall not be used for any other purpose. In this combination one of the colours shall cover at

least 30 % and at most 70 % of the surface being coloured, while the other colour shall cover the remainder of the

surface.

Single-core cables that are coloured green-and-yellow throughout their length shall only be used as a protective

conductor and shall not be overmarked at their terminations, except as permitted by Regulation 514.4.3.

A bare conductor or busbar used as a protective conductor shall be identified, where necessary, by equal green-andyellow

stripes, each not less than 15 mm and not more than 100 mm wide, close together, either throughout the

length of the conductor or in each compartment and unit and at each accessible position.

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, in addition, green-and-yellow markings at the terminations.

 

[Geoffsd]

Has it already been said?

Whether or not oversleeving the cpc is allowed, it cannot normally be done while complying with 412.2.3.2

 

[uksparks]

Single-core cables that are coloured green-and-yellow throughout their length shall only be used as a protective conductor and shall not be overmarked at their terminations

I think that really makes it quite clear.

 

[SPARTYKUS]

I think its rather laughable that the NICEIC have actually condoned it in an article.

 

[MDJ]

I think its rather laughable that the NICEIC have actually condoned it in an article.

Yes they are trying to re write the regs. Lets look at this from another aspect, where in the regs does it say it is acceptable to use a green and yellow conductor for a live conductor even if the conductor is marked? It won't, it just won't.

 

[Silly Sausage]

I had an NICEIC publication once, I burnt it.

 

[uksparks]

The snags and solutions books are quite good actually, handy to see examples etc...

 

[MDJ]

The snags and solutions books are quite good actually, handy to see examples etc...

Yes I have a couple, they make up rules in them unfortunately, I like the earthing and bonding edition, it is hilarious in places.