Why cover earth wire?

[Ziggie]

for T@E cable, we cover the bare earth wire with a sleeve of green / yellow. Why?
The basic idea is that if there is a fault then the live wire meets with the earth and covering the wire with insulation potentially stops this action in some cases. Is it not better to have the bare wire to increase the chance of making contact with a live?

I realise that it makes it easy to identify, but all other cables have coloured sleeves.

 

[Ziggie]

Whether we agree with a particular reg or not, or trust the wisdom of those who compile the regulations, we still have to follow what they say. Otherwise what's the point of having regulations in the first place? ?

I agree . No one said don’t obey the regs. But that does not and should not stop questioning them. Free speech

 

[stevethesparks]

I agree . No one said don’t obey the regs. But that does not and should not stop questioning them. Free speech

I'd still like a proper answer to 411.5.1 as in the Electrical Wiring, Theories and Regulations section

 

[nicebutdim]

I agree . No one said don’t obey the regs. But that does not and should not stop questioning them. Free speech

This is a moderated forum, not an open platform. Probably best to keep politcs in dedicated threads.

 

[static zap]

Keeps cable costs down having the CPC naked, we are just used to sleeving this type of cable.

I like to think a bare cpc makes detection of cable damage quicker with a bit of water about ... We are in the UK - Not France / Spain.

( I don't have any plumbing tendencies ... applies ldf )

 

[7029 dave]

I like to think a bare cpc makes detection of cable damage quicker with a bit of water about ... We are in the UK - Not France / Spain.

( I don't have any plumbing tendencies ... applies ldf )

And wait for the bubbles to appear eh.lol

 

[Ziggie]

because you don't want a L -E fault to occur except when and if there's a fault with the accessory/equipment. or wiring.

Let’s take a case where the insulation of the live conductor is damaged. If the CPC is insulated then no action occurs. Is it better to do the best one can by having a bare CPC which would in some cases cause the protection to fail and continue to do so until the fault is fixed.
More interesting is if there was a fault in the N where the connection of earth to neutral might exist unnoticed for some time.

of course, insulation testing would reveal the problem

sounds like I am discussing wrapping the conductors ( both L and N ) and turning them into SWA like cables?
Is the question “ why isn’t the earth in SWA cable covered in yellow / green insulation” ??

 

[loz2754]

The purpose of a CPC, as I understand it, has nothing to do with protecting the cable in the case of damage, eg by nail penetration etc.
But rather to provide connected equipment with a means of connection to the main earth terminal to facilitate ADS in the event of a fault in the equipment.
Please correct me if this is an incorrect correction...

 

[Lucien Nunes]

It doesn't protect the cable per se but it can protect the numpty who drives a nail into it. The closer the CPC is to an energised conductor, the more likely that a nail that contacts the energised conductor will contact the CPC too, and hence trip the protection instead of just making the nail live. If you want full protection against that then the CPC needs to surround the other cores with enough CSA to take the hit e.g. Flexishield or SWA. But a fair percentage of T+E 'penetration incidents' probably benefit from the presence of the CPC.

 

[Ziggie]

It doesn't protect the cable per se but it can protect the numpty who drives a nail into it. The closer the CPC is to an energised conductor, the more likely that a nail that contacts the energised conductor will contact the CPC too, and hence trip the protection instead of just making the nail live. If you want full protection against that then the CPC needs to surround the other cores with enough CSA to take the hit e.g. Flexishield or SWA. But a fair percentage of T+E 'penetration incidents' probably benefit from the presence of the CPC.

I was beginning to think that the L and N cores should be wrapped in foil and hence protect from cable damage.This would act as a significant cross sectional area for a CPC.
If the main purpose is to provide an earth to the equipment, then putting on yellow /green cladding doesn’t add anything as it doesn’t cover the screw or clip attachment.
This borders on if you have a cable running to equipment that doesn’t use an earth (eg nest controller) , should one run a CPC to it. The normal answer is yes in case the next job is to replace the kit with something that needs an earth but I always thought that it was to give a little protection against the nail

 

[pc1966]

I was beginning to think that the L and N cores should be wrapped in foil and hence protect from cable damage.This would act as a significant cross sectional area for a CPC.

For cables that absolutely need such protection (e.g. non-RCD with risk of nail penetration, etc) you can get Flexishield cable as an intermediate between normal cables (T&E or 3-core, etc) and SWA with its physical protection as well.

Flexishield also seems to last well on farms, etc, according to a spark we have used who does a lot of industrial and agricultural work. Also they do a cat urine flavoured version specifically for that:

Flexishield R How It Works

Flexishield R How It Works

www.flexcables.co.uk

 

[jay sean]

when I was a apprentice in the late 90s, im sure there was a twin and earth were the earth was sleaved,

 

[Ziggie]

when I was a apprentice in the late 90s, im sure there was a twin and earth were the earth was sleaved,

This is common in Ireland.

 

[westward10]

when I was a apprentice in the late 90s, im sure there was a twin and earth were the earth was sleaved,

I remember working a site in the UK in the late 80s early 90s can't remember exactly but we installed a load of 1.5 with sleeved cpc, didn't take much notice at the time but all other sizes had bare cpcs.

 

[nicebutdim]

This is common in Ireland.

It wasn't in the 90s.

 

[LastManOnline]

but there is an argument in favour of least use of the Earth's resources which the RFC and T&E construction were originally driven by.

If so, then that is very noble.