Conduit cabling sizes

[cliffed]

Helping out a fellow spark, 2nd fixing,nice school extension.
Have the regs changed,concerning cpc sizes with cables.
It’s all been specificed by consultant,the circuits are radials,which is a good thing.
Bit confused about the sizing of the cpc,obviously single cabling,4.0mm live & neutral,the strange thing is that the cpc is 2.5mm.
I always thought this should be 4.0mm,it this situation.

 

[Pete999]

Ok ,in this day & age,never just relied on the conduit for earth,always installed a cpc.

Why do you reckon that i cliffed?

 

[Pete999]

Ok ,in this day & age,never just relied on the conduit for earth,always installed a cpc.

Why do you reckon that i cliffed?

 

[MDJ]

Have the regs changed,concerning cpc sizes with cables.
.

Why don't you buy a copy of the regs and have a look

 

[cliffed]

Why wouldn’t you add a cpc,it’s specificed anyway.

 

[cliffed]

Why don't you buy a copy of the regs and have a look

T

Why don't you buy a copy of the regs and have a look

funny ha ha

 

[MDJ]

T

funny ha ha

You stink haha, thats funny

 

[drzsta]

If your using galv why are you running a separate CPC?

Designers can't depend on the integrity of the installation nowadays and hence rightly specify separate CPC conductors.

The quality of kit available now is atrocious, brass bushes are paper thin and I'm comming across malleable boxes that are not threaded straight which is irksome for besa mounted lighting runs that you want perfectly lined up. I think most of this carp is now cast in China.

 

[Ian1981]

Designers can't depend on the integrity of the installation nowadays and hence rightly specify separate CPC conductors.

The quality of kit available now is atrocious, brass bushes are paper thin and I'm comming across malleable boxes that are not threaded straight which is irksome for besa mounted lighting runs that you want perfectly lined up. I think most of this carp is now cast in China.

100% Agee with you regarding the crooked besa boxes, very disappointing

 

[cliffed]

I was always taught,cpc same size in single cabling,conventionally/conservatively,this was always done.
Obviously using the abriactic equation,the cpc is smaller.
T/e is calculated for that purpose,most swa cabling the cpc are the same as the live & neutral.
Will be happy to do this now,after sizes were specified,on this job.
If I personal install cabling,most probably stick to cpc same size as live.
Other than that,the equation may be activated,& see how that performs.
Thanks for all replies.

 

[Ian1981]

100% Agee with you regarding the crooked besa boxes, very disappointing

Agree even haha

 

[davesparks]

I was always taught,cpc same size in single cabling,conventionally/conservatively,this was always done.
Obviously using the abriactic equation,the cpc is smaller.
T/e is calculated for that purpose,most swa cabling the cpc are the same as the live & neutral.
.

In SWA the cpc is always a different size, and a different material for that matter. It’s only if you use a cable with an extra core (eg 3 core for single phase) to use as a cpc that you get one the same size.

 

[Deleted member 26818]

Been installing conduit now for over 30 years.
In the last year or so I have found some conduit where the Galv coating flakes off on the back of bends.

 

[cliffed]

In SWA the cpc is always a different size, and a different material for that matter. It’s only if you use a cable with an extra core (eg 3 core for single phase) to use as a cpc that you get one the same size.

Agree,usually not using sheath for a cpc,using extra core instead.

 

[cprfenom]

I am not sure why you question it if you are helping a mate and someone else has design responsibility.

I know that they come up with some stupid calculations, but they have to put their name to the certification.

That said I do enjoy the 20m 4.0mm2 rings

 

[cliffed]

Agree,I just never did it,cpc were the same size as conductors in conduit cabling,that’s all.