Connections Mag - Issue 185 - Big Mistake, Methinks

[NozSpark]

IIRC that part of the article was on about 'on view' flexes supplying class 2 equipment...

I haven't checked the regs though, but I wouldnt do it anyway

 

[Nicky Tesla]

Pretty sure all points of utilisation are required to have a cpc present eg switches ceiling roses etc

that reg is only in place in case somebody changes the plastic fitting for a metal one, in such a case the cpc is there ready to connect.  If there is a metal back box the cpc will be required anyway.

On a dedicated smoke alarm circuit there is no chance for the detectors to get changed for a metal smoke detector so no cpc required.

 

[Jono Pashley]

that reg is only in place in case somebody changes the plastic fitting for a metal one, in such a case the cpc is there ready to connect.  If there is a metal back box the cpc will be required anyway.

On a dedicated smoke alarm circuit there is no chance for the detectors to get changed for a metal smoke detector so no cpc required.

Utter rubbish cpc isnt there JUST for class 1 fittings, thats why it is a circuit protective conductor not a class 1 fitting protective conductor

 

[Nicky Tesla]

what are YOU talking about ......... what purpose does it serve in your head then?

 

[msb2003]

The NICEIC published this some time ago and at the time I though it strange. I work in a college so checked with a senior lecturer and we agreed that while it technically may be allowed to use the green/yellow of a multicore cable, it is not good practice. The regs do say the green/yellow should be used exclusively for the cpc. They also state single core cables cannot be used in this way. I would assume this is because if they were cut along their length there would be nothing to indicate they could be carrying current.

Having checked other text books, the ECA guide to the wiring regulations also state this is allowed and there was an article in professional electrician regarding this (they said similar to me, technically ok, but not good practice).

Secondly, I guess Jono means that the CPC also protects the cable should it get damaged, not just earthing a class 1 appliance

 

[Jono Pashley]

what are YOU talking about ......... what purpose does it serve in your head then?

YOUR the one who thinks he can go around sticking smoke alarms in with no cpc in the cable why dont you justify that. YOUR the one who seems to believe the cpc is there just for the benefit of class 1 items, bust as usual you bring ZERO justification.

 

[batty]

Cos.your not allowed a switched socket to feed a boiler .

In an ideal world you have a spur or an unswitched socket but the customer knows the socket feeds the heating system so they are not likely to switch it of. I did offer to replace it or put a label on the plug. It just seems strange to me they except heating systems with the green & yellow used as switch lives but get on there high horse when a customer has a switched socket feeding the heating system.

that reg is only in place in case somebody changes the plastic fitting for a metal one, in such a case the cpc is there ready to connect.  If there is a metal back box the cpc will be required anyway.

On a dedicated smoke alarm circuit there is no chance for the detectors to get changed for a metal smoke detector so no cpc required.

So you install a smoke alarm circuit how are you going to test the earth fault loop if you have used the cpc as the interlink. I suppose you could test live to neutral and put that down as a thingy on your test certificate. Its a bit late for remembering certain words.

 

[kme]

Right.

Spoke to NIC area engineer today; who, although he isn`t ( and doesn`t work for) god; does know the regs book inside out.

He doesn`t like it either, although his opinion was that it was bad practice, it is not prohibited by regs. Further, he didn`t believe it was appropriate for that to be printed in the manner it was.

Now - ( thanks Andy) 411 was the bit I was thinking of. a class 2 fan is NOT a pendant - ergo it IS prohibited.

Nicky - I asked a while ago for either yourself or Adrian to find me a reg that allows this practice - neither of you have - you`ve just butted heads with other members ( as usual).

It would be really good to have an honest, adult debate about this - if a debate is warranted. 

I would have ( and would continue to) code this on an EICR, because, in my opinion it does not comply with 411.

I accept that 514 refers to a single conductor; rather than a multicore; but it does NOT say that " a multicore cable may have its conductors labelled, including the cpc, as anything the installer chooses"

And, to wade in on the "requirement for the cpc"........

Just suppose the householder wants to alter something, and feels competent to do so. the switch off, and cut in t flex, to tap in for something else. Irrespective of anything else; they will KNOW the g/y  is an earth; and may well attach it to an exposed conductive part of their add-on - the first time they know different is when the g/y switched live is in the "on" position, whilst someone touches the e.c.p in question.

Would YOU stand in a courtroom and say " I couldn`t find a regulation to preclude it"?

Isn`t this why they make and sell 4 core flex?

Another option - the flex gets nicked / damaged - it doesn`t matter, thats only the earth wire............bang!

thoughts?

 

[Adrian]

I did not reply to the post with a regs number because I am at home on the sick with a broken back and can't get to the office for the regs book.

I did not butt heads with other members over this (check posts) instead I butted out because the reason above

so kme do you now agree with me and Nicky that it is not prohibited by regs on multicore cables to use the cpc

as my second post I agreed it is in my opinion bad practice, and I would not do it.

post like batty about getting jobs with British gas and Steptoe about having good insurance was not called for

 

[wozz]

Kme I was with you until "householder cuts into flex" I don't think 7671 asks for us to account for morons. If the householder isn't commentary to check for dead and they shouldn't be touching anything.

I don't like it and I wouldn't do it is my stand. 

 

[Andy™]

I did not reply to the post with a regs number because I am at home on the sick with a broken back and can't get to the office for the regs book.

I did not butt heads with other members over this (check posts) instead I butted out because the reason above

so kme do you now agree with me and Nicky that it is not prohibited by regs on multicore cables to use the cpc

as my second post I agreed it is in my opinion bad practice, and I would not do it.

post like batty about getting jobs with British gas and Steptoe about having good insurance was not called for

FFS. read post 4, where i stated the reg which specifically prohibits a G/Y coloured conductor from being used for anything other than a CPC

 

[Evans Electric]

I read that at the time it was published.

i kept quiet as I thought I had misread or missed something and did not wish to look more stupid than usual

Why ?   You don't usually worrry about it  :innocent   :innocent  

 

 

 

[steptoe]

I did not reply to the post with a regs number because I am at home on the sick with a broken back and can't get to the office for the regs book.

I did not butt heads with other members over this (check posts) instead I butted out because the reason above

so kme do you now agree with me and Nicky that it is not prohibited by regs on multicore cables to use the cpc

as my second post I agreed it is in my opinion bad practice, and I would not do it.

post like batty about getting jobs with British gas and Steptoe about having good insurance was not called for

well,

I quite often deviate from the regs,

but,

in this case I still think you need really good insurance,

why do you think it was uncalled for?

you have left the install not only non compliant, but in a possibly seriously lethal condition.  :shakehead

insurance companies love people like you, they take your money, and you write your own get out clause......

 

[batty]

its fine with me to as long as its sleeved but not ok on t&e because the cpc is not insulated along its lengh 

Well if you think its ok to sleeve a green/yellow with another colour as you can't be bothered to put the correct cable in you really should get a job with British Gas because that is what they do and they will accept installs like this.

 

[Nicky Tesla]

From the reg posted earlier:

"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 as per regulation 514.4.3."

This paragraph is about single core cables not multicore cables.  Specifically these single core cables shall not be overmarked at their terminations,  implying that cables other than single core are permitted to be overmarked.  Reg 514.4.3.  is just about  PEN conductors where a blue colour is added  and therefore irrelevant  to this discussion.

From MSB2003

"Secondly, I guess Jono means that the CPC also protects the cable should it get damaged, not just earthing a class 1 appliance"

in what way does it protect the cable?  do you mean that if somebody bangs a nail in it or something the mcb will trip in good time?

Well what would happen if somebody banged a nail in and shorted L/N ?  very much the same i would say if you know how mcbs work except the neutral being the same size conductor as the live can handle greater current.

FRom Batty

"So you install a smoke alarm circuit how are you going to test the earth fault loop if you have used the cpc as the interlink. I suppose you could test live to neutral and put that down as a thingy on your test certificate. Its a bit late for remembering certain words."

You just want to know the Zs of the smoke alarm circuit just so you have a number to fit in your box on the cert....no other reason

WhY do we take Zs readings?   So if someone touches a metal part of the circuit that has become live ( such as a metal back box) then if they touch another metal object at the same time the chances of getting a fatal shock are less.  Also if the back box becomes live this will short to earth via the cpc and trip the MCB to prevent the back box remaining live.

     Do any of these reasons apply to a smoke alarm?    Are your smoke alarms metal?   Do you fit them using metal back boxes?

"You could test live to neutral and put that down as a thingy on your test certificate"  or N/A even,  because the value of ZS is irrelevant.

You can wire smoke alarms in 6 core cable if you wish but only 2 to 3 core will be of any purpose.

From KME

"Nicky - I asked a while ago for either yourself or Adrian to find me a reg that allows this practice - neither of you have - you`ve just butted heads with other members ( as usual)."

You quote the same regs as me like the one above but you seem to read it with blinkers on.

 

[Nicky Tesla]

Thats correct  so if the green/yellow cable is overmarked then it ceases to be a green/yellow cable. Overmarking is permitted on multicore cables but not single core cables as shown in the original paragraph..............again your reading these regs with blinkers on. 

 

[Nicky Tesla]

i was wondering if people knew what blinkers were when i posted it

 

[Marvo]

Just to avoid confusion;

 

[Nicky Tesla]

i was definitely focussed watching that vid  

 

[steptoe]

@ holliesmum