Why is the earth wire not insulated

[grahame]

:tongue3:I was asked the question “Why is the earth wire not insulated in twin and earth cable, yet you can purchase a sleeve to cover it?”
My first thought was what a daft question but on reflection is it? And I couldn’t give the person a straight forward answer. I guess it has something to do with the earth wire picking up current leakage if damage occurred to the cable exposing the live/neutral conductors. But can any one give me a answer ?

 

[1shortcircuit]

This has been covered before in another thread as I remember asking the question... Would you want it to be insulated? It would make stripping the pvc a right butt ache

 

[telectrix]

terminology again....... it's not an earth wire it's a............. stripping cord. get it right.

 

[Knobhead]

It's cheaper?

 

[grahame]

Now there’s a lateral answer

 

[spud1]

Manufacuring costs most I would expect, also overall size of cable reduced making installation easier. Its not a live conductor, doesnt require double insulation so why insulate and sheath it if it doesnt have to have it

 

[benji]

might become live in a fault condition

 

[brooky25]

Could possibly provide better fault protection if cable is damaged ie nail etc.. If it was sleeved you may just catch line conductor. Just a thought

 

[ian.settle1]

might become live in a fault condition

Yes but as it has sleeving at the ends and is withhin the outer sheathing you should not be able to touch it

 

[Smudge]

...just incase you need it as a strapper if you forget to run a 3 core...

 

[Amp David]

might become live in a fault condition

As would every other piece of metallic equipment that had a CPC connected to it.

 

[kamkam]

Could possibly provide better fault protection if cable is damaged ie nail etc.. If it was sleeved you may just catch line conductor. Just a thought

That's what I was told by an 'old timer' sparks

 

[Plonker 3]

As would every other piece of metallic equipment that had a CPC connected to it.

Which SHOULD include the M.E.T. so no problem there then.

 

[SparkyDips]

...just incase you need it as a strapper if you forget to run a 3 core...

lmao brilliant!!

 

[Amp David]

Never said there was.

 

[Rockingit]

Interestingly, I wired an exhibition stand a few years ago which was due to go to various shows in different countries and part of the requirements was that the cpc HAD to be sheathed throughout, and in a flat cable format.

Never did figure out why, and finding the cable was a sod!

 

[SparkyDips]

finding the cable was a sod!

did you manage to get some??

 

[jay sean]

Im sure when I was an apprentice, i used a twin and earth where the earth was sleaved, this was in the mid 90s

 

[jase]

Twin & Earth Australia Wire 4mm - China Electrical Wire,Cable in Electric Wire & Cable

when i was working in australia the earth was already sleeved in twin and earth like in this link

 

[Rockingit]

I did end up with a roll of 2.5 x 3 in brown, blue and g/y, but I can't remember what it officially was or where it came from! Time wise, would have been 2000-1 ish.