CPC as live conductor now OK?

[ecowarrior]

I note in this months Connections (NIC mag) the article on using cpc sleved as a live conductor. It would appear that using flex to a class 2 unit (that doesn't need a cpc that the cpc can in fact be used as a switched live. In the very next paragraph (514.4.2) says it shall not b used for any other purpose. I thought every flex except from a light pendant had to have a cpc?

 

[JohnW2]

I thought every flex except from a light pendant had to have a cpc?

You're talking about fixed wiring. For better or worse, most flexible cables connected to portable Class 2 Appliances are 2-core, without a CPC.

Kind Regards, John

 

[ecowarrior]

So if fitting a class 2 Honeywell 927 stat with a multicotre flexi Its now deemed OK to use the cps sleeved up as a live conductor?

 

[EFLImpudence]

NIC often make up their own rules.

 

[Spark123]

It depends. If you want to be known for being rough then yes, if you want to do a quality job then use 3c+e

 

[EFLImpudence]

So if fitting a class 2 Honeywell 927 stat with a multicotre flexi Its now deemed OK to use the cps sleeved up as a live conductor?

No, because you must run a cpc to the point.

Not starting this again, are we?


Believe whoever you want or read the regulations.

 

[PrenticeBoyofDerry]

Unfortunately niceic, make there own rules up that contradict BS7671.
In a court of law I would like to think that my work complied to BS7671, rather than an article attributed to niceic! They are not going to come and save your sorry arse!

 

[ecowarrior]

Not starting this again, are we?

FFS no! just struggled to believe it when I read it.

 

[AdrianUK]

Did you not know that they are the "NICEIC wiring regulations" .... as quoted from a particular website ....

 

[RF Lighting]

Was it the NICEIC website?

 

[OwainDIYer]

I suppose you could use a 3-core flex or cable eg between the flex outlet plate and an double-insulated extractor fan for live/switchedlive/neutral and omit the earth.

However the conductor identified green/yellow MUST NOT be used as anything other than earth and as flex (usually) has its conductors coloured throughout that rules out using flex in this way. I suppose an exception would be a double-insulated light fitting with the lamps wired on two separate switches for variable light levels and wired in transparent decorative flex identified by coloured sleeves only at the ends.

On T&E cables the E is of reduced size, which would rule out using it as anything other than an earth in most situations, unless you oversize and use a 2.5mm T&E where the reduced earth size is still acceptable. And, of course, it's not insulated and sheathed so would have to be run in conduit.

 

[DaftPunk]

How could you do that and still comply with regulation 411.3.1.1 "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"

Are fans and light fittings no longer a point in wiring or an accessory?

 

[leeco]

On a job I have just done I had twin and earth running from 2 switches also 3 and earth running fron the same switches. The switches controlled 2 lights on 2 floors, on one floor it was looped in at the lights and got its earth from there on the other floor it was looped in at the switch that had its own earth so the earth wires that was running between each switch wasn't needed so was used in the L2 for the other light but had brown sleeving on.

Was that bad practice?

 

[DaftPunk]

Not bad practice, that's disgraceful. You can not under any circumstances ever use the CPC in twin and earth as a live conductor.

 

[ericmark]

I would never over sleeve a wire coloured as earth to use it for any other use. However the centre core of twin and earth is not coloured as an earth wire even though we all know that is what it is for.

So 514.4.2 does not apply with twin and earth as it's not "The bi-colour combination green-and-yellow".

Although I think it would be bad practice to use the centre core for anything other than earth I am struggling to find a regulation banning it.

Table 52.3 - Minimum cross-sectional area of conductors would seem to in some ways stop it's use if under 10mm but rather stretching it a bit. 559.11.5.3 Bare conductors is another but is the centre conductor of twin and earth really considered as a bare conductor?

So I repeat I think it's bad practice to use the centre conductor of twin and earth for anything else other than earth but I can't find a regulation banning it from being used for other than earth. I had not even thought about it before but lets see if any one can find a regulation stopping the use of the centre conductor for other than earth?