NICEIC Certification Scheme NICEIC’s Connection magazine (using CPC as a live conductor)?

[stuartcourt]

I have even always ran a four core to double insulated tank stats to take a cpc along, what a nob cant believe it, but no more 3 core all the way off out now to have a long hard think

 

[Amp David]

Good practice though stu, at least there's a CPC there if it ever gets swapped for one that requires the CPC

 

[Guest55]

work smart and keep that cash firmly in pocket.
:-D

 

[chopper76]

NICEIC’s Connection magazine (using CPC as a live conductor)?

The cable may not contain a cpc in this way of wiring said extractor fan, and as previously stated there isn't a requirement just to protect the cable but if you are concerned about damage it does carry a neutral within it anywhoo

 

[vaughant]

Seen it done in industry a few times but generally as a bodge!!!!

 

[Tim]

well, i wouldn't do it. 514.4.2. for one.

From 514.4.2:
"Single-core cables that are coloured green-and-yellow throughout their length shall only be used as a protective conductor and shall not be over-marked at their terminations, except as permitted by Regulation 514.4.3 [PEN conductors]"

That reg only covers single core condutors as far as im aware (correct me if im wrong) so a flex G/Y suitably sleeved should be ok.

I found this on a eicr recently and didnt code it as it was correctly sleeved, posed no danger and did not break any regs by my interpretation.

Ill happily be corrected if im wrong.

Tim

 

[GLENNSPARK]

I think you have.

Its refering that you can use the green and yellow core wthin a flex as a live/neutral conductor, as long as you flag it thus at both ends. But certainly not a cpc within a twin and earth cable, as it would only be single insulated and carrying a voltage over 50 volts and not satisfying basic protection.

As most fans are class II/double insulated/reinforced insulated, they don't require to be connected to earth, and as most modern fans incoroporate a run on timer. It will save having to rewire them with 4 core to replace the 3 core.

There are still electricians that think you can't use a green and yellow core within a flex as a live/neutral conductor? And they are just veryifyng, its not a departure if used as one.

no it bloody wouldn`t...
there would be no insulation on this at all....sheething is not classed as insulation
so, explain please why the CPC is not insulated in flat cable...

 

[somersetsparks]

It has always been Acceptable to use the G/Y core of a flex sleeved as a live conductor as far as I'm aware,
Another case of you wouldn't do it if you had to install the cable, but you would definately do it to save smashing up a bathroom

 

[telectrix]

From 514.4.2:
"Single-core cables that are coloured green-and-yellow throughout their length shall only be used as a protective conductor and shall not be over-marked at their terminations, except as permitted by Regulation 514.4.3 [PEN conductors]"

That reg only covers single core condutors as far as im aware (correct me if im wrong) so a flex G/Y suitably sleeved should be ok.

I found this on a eicr recently and didnt code it as it was correctly sleeved, posed no danger and did not break any regs by my interpretation.

Ill happily be corrected if im wrong.

Tim

you quoted para.2 of the reg. i was referring to para.1. no mention of single core in there.

 

[Richard Burns]

If you have used a three core flex and sleeved the green and yellow to use as a live conductor, then unless you also run a separate cpc then you would no longer be complying with 411.3.1.1 that requires a cpc at every accessory and joint (bar a lampholder).

I would, unfortunately, agree that it is possible to use a green and yellow insulated core of a multicore cable for a live conductor if suitably sleeved, but I would definitely not like it; based on the section Tel identifies that says green and yellow is a protective conductor only; admittedly the sleeving "makes it" non green and yellow but still would not like to do it.

 

[chilliwilly]

no it bloody wouldn`t...
there would be no insulation on this at all....sheething is not classed as insulation
so, explain please why the CPC is not insulated in flat cable...

Insulation is used as a method of basic protection, a bare cpc is insulated in a sheathed cable due to the nature of its design and manufacture, and remains insulated until terminated or damaged, if it wasn't it would be exposed and causing further exposure to the inner single insulated cores. You would also be able to measure a potential difference between a live conductor and the cpc within a sheathed cable if it wasn't insulated?

The cpc core would also have a high insulation resistance when being tested against another cpc core within another sheathed cable within the same bunch or enclosure?

And in the case of a sheathed cable insulating the bare cpc core, it offers protection against corrosion with a humid environment. But as previously mentioned cannot be designed to be permanantly connected to votage above 50v without another layer of insulation offering increased basic protection?

Also where a twin sheathed cable is used to supply a LV circuit to a class I accessory, a minimum size of 4mm single insulated cable has to be used as a cpc. Or it can be rewired with a twin and earth, the cpc being smaller than the live conductors. And the cpc within the sheath affording the same insulation value, and carrying a satisfactory level of fault current to disconnnect the circuit protection device, as that of the 4mm single insulated cable, except the 4mm cable would offer a lower r2 reading and potentially allowing a higher level of fault current?

The above isn't an exhaustive list, but provide some examples of a sheath offering insulation?

In the meantime I hope this explains why a cpc is bloody insulated in a sheathed cable?...

 

[GLENNSPARK]

Insulation is used as a method of basic protection, a bare cpc is insulated in a sheathed cable due to the nature of its design and manufacture, and remains insulated until terminated or damaged, if it wasn't it would be exposed and causing further exposure to the inner single insulated cores. You would also be able to measure a potential difference between a live conductor and the cpc within a sheathed cable if it wasn't insulated?

The cpc core would also have a high insulation resistance when being tested against another cpc core within another sheathed cable within the same bunch or enclosure?

And in the case of a sheathed cable insulating the bare cpc core, it offers protection against corrosion with a humid environment. But as previously mentioned cannot be designed to be permanantly connected to votage above 50v without another layer of insulation offering increased basic protection?

Also where a twin sheathed cable is used to supply a LV circuit to a class I accessory, a minimum size of 4mm single insulated cable has to be used as a cpc. Or it can be rewired with a twin and earth, the cpc being smaller than the live conductors. And the cpc within the sheath affording the same insulation value, and carrying a satisfactory level of fault current to disconnnect the circuit protection device, as that of the 4mm single insulated cable, except the 4mm cable would offer a lower r2 reading and potentially allowing a higher level of fault current?

The above isn't an exhaustive list, but provide some examples of a sheath offering insulation?

In the meantime I hope this explains why a cpc is bloody insulated in a sheathed cable?...

again....sheathing is not classed as insulation....its there to provide a degree of mechanical protection to the insulated cores underneath!!!
further more you still have not explained why the CPC is not insulated on flat twin....have you...
and theres a very good reason for it.....

 

[chilliwilly]

again....sheathing is not classed as insulation....its there to provide a degree of mechanical protection to the insulated cores underneath!!! WELL I NEVER!!! Mind you the trouble is though, by default it insulates the bare cpc ? Even though not designed for that purpose, as WE ALL KNOW.But does offer a degree of protection against corrosion?

further more you still have not explained why the CPC is not insulated on flat twin....have you... But if it was insulated, it could be used as a 3 core like the flex in this thread?

But as it isn't insulated, and doesn't require insulation as it isn't a live conductor, it can't be used as a live conductor can it?

That reminds me, I'm going to send my fluke multi tester back, there must be something wrong with it, everytime I try to measure volts to earth between live and the pvc sheath of a twin and earth, it displays 0 volts?

But when I measure between the cpc terminal with the cpc of the same cable, it measures a voltage?

Come to think of it, measures a voltage between live and anything with an earth potential? But not on PVC or any other material used for insulating electrical conductors?

I'm going to send it back, I can't believe I paid all that money for it and it has an intermittent fault? Come to think of it, they all have the same fault, every meter and tester I've had has had the same fault for nearly 40 years? I can't understand it?

In fact, the same thing happens when I test for voltage between live and the pvc sheath of an armoured, an FP, a flex, a porcelain pillar, a porcelain sink and bath, a pvc matt on a chacker plate gantry, an insulated enclosure, plastic conduit and trunking, and some other thingys, oh I nearly forgot... and the air?

And I think that's it without taxing my brain.

Maybe you know what could be wrong with my meters?

 

[GLENNSPARK]

again....sheathing is not classed as insulation....its there to provide a degree of mechanical protection to the insulated cores underneath!!! WELL I NEVER!!! Mind you the trouble is though, by default it insulates the bare cpc ? Even though not designed for that purpose, as WE ALL KNOW.But does offer a degree of protection against corrosion?

further more you still have not explained why the CPC is not insulated on flat twin....have you... But if it was insulated, it could be used as a 3 core like the flex in this thread?

But as it isn't insulated, and doesn't require insulation as it isn't a live conductor, it can't be used as a live conductor can it?

That reminds me, I'm going to send my fluke multi tester back, there must be something wrong with it, everytime I try to measure volts to earth between live and the pvc sheath of a twin and earth, it displays 0 volts?

But when I measure between the cpc terminal with the cpc of the same cable, it measures a voltage?

Come to think of it, measures a voltage between live and anything with an earth potential? But not on PVC or any other material used for insulating electrical conductors?

I'm going to send it back, I can't believe I paid all that money for it and it has an intermittent fault? Come to think of it, they all have the same fault, every meter and tester I've had has had the same fault for nearly 40 years? I can't understand it?

In fact, the same thing happens when I test for voltage between live and the pvc sheath of an armoured, an FP, a flex, a porcelain pillar, a porcelain sink and bath, a pvc matt on a chacker plate gantry, an insulated enclosure, plastic conduit and trunking, and some other thingys, oh I nearly forgot... and the air?

And I think that's it without taxing my brain.

Maybe you know what could be wrong with my meters?[/QUOTE]



not what you stated at #2

clearly you didn`t...otherwise you would not have made the statement at #2 that you did

again not what you stated at #2....you implied the sheath was classed as insulation....which it isn`t...regardless of any insulating qualities it may have.....
so dont blame the tools...

i havn`t once blamed your test gear....

and you still havn`t answered the (very relevent question) i posed to you at #22 & #27 which was why does the CPC on a flat cable not have any insulation along any of its length?
nearly 40 years in the game....you should know then.....
i suspect you dont....
answer today please

 

[Darkwood]

you quoted para.2 of the reg. i was referring to para.1. no mention of single core in there.

I think your misinterpreting this reg first paragraph simply states that the use of green and yellow combination is exclusively reserved for earth meaning you cant mark a live/neutral with green/yellow it not mean you cant sleeve a g/y with rown or blue and alter its identity.
Having said that Ill agree its a practice I wouldn't do myself.