Twin + Earth - no sleeve on earth

[Nope]

Hi DIYers!

I’ve recently been doing some DIY electrical work and have, of course used earth sleeve on my Twin + Earth cables.

But here’s something I’ve always wondered - why do they not just supply the cable with earth already sleeved? Three core flex has the earth wire sleeved, so why not T+E? Is there a reason for it?

 

[terryplumb]

It's cheaper for one thing !

 

[Nope]

It's cheaper !

And that’s the only reason? Well they do say that money makes the world go round, don’t they?

 

[EFLImpudence]

Also it is not necessary; T&E is flat with the CPC in the middle so it's not like flex.

I’ve recently been doing some DIY electrical work and have, of course used earth sleeve on my Twin + Earth cables.

What about asking why it is necessary to sleeve it?

 

[Tigercubrider]

It all adds up.
United Airlines used to run a competition for ideas.
One employee suggested using thinner paper for the inflight magazines.
The tiny weight change save 170,000 gallons of fuel ($290,000 a year)

 

[JohnW2]

And that’s the only reason? Well they do say that money makes the world go round, don’t they?

There's one other possible reason that I've heard suggested, although I have no idea as to whether there is any truth in it ... by having the earth wire bare, and between the (insulated) L and N conductors, then should the insulation of either of the others become damaged, the L (or N) conductor is more likely to come into contact with the earth one, and cause a protect device to operate (blow a fuse or 'trip' an MCB or RCD).

Kind Regards, John

 

[Murdochcat]

Eire uses t&e with all 3 cores insulated

 

[JohnW2]

Eire uses t&e with all 3 cores insulated

Indeed they do - as do a good few other countries.

Kind Regards, John

 

[EFLImpudence]

Have they always had that or did they have a good reason to change?

 

[Nope]

There's one other possible reason that I've heard suggested, although I have no idea as to whether there is any truth in it ... by having the earth wire bare, and between the (insulated) L and N conductors, then should the insulation of either of the others become damaged, the L (or N) conductor is more likely to come into contact with the earth one, and cause a protect device to operate (blow a fuse or 'trip' an MCB or RCD).

Kind Regards, John

That’s an interesting suggestion, and rather a logical one too!

 

[JohnW2]

Have they always had that or did they have a good reason to change?

Dunno - but I suspect that, like much of the world, they probably initially just 'followed the UK'.

As for 'reasons', who knows? AS far as safety issue are concerned, the only think I can think of is what I've already mentioned, and that would seem to favour having a bare CPC.

Of course, at least now, Eire doesn't seem to like/'allow' over-sleeving at terminations, so maybe it's just that they didn't like the idea of G/Y sleeving at then ends?

Kind Regards, John

 

[JohnW2]

That’s an interesting suggestion, and rather a logical one too!

Maybe too 'logical' for that to be the reason The more 'cynical' reasons are probably more likely!

Kind Regards, John

 

[Risteard]

Have they always had that or did they have a good reason to change?

The Free State changed in September 2017 to full size, insulated protective conductors. That said, not all sizes previously tallied with BS cable - e.g. 16mm^2 T&E had a 10mm^2 protective conductor for the I.S. version rather than 6mm^2. It has since changed again that all cables must be a minimum of Dca, -s2, d2, a2 - so essentially to be simplistic about it LS0H.

 

[Risteard]

Dunno - but I suspect that, like much of the world, they probably initially just 'followed the UK'.

As for 'reasons', who knows? AS far as safety issue are concerned, the only think I can think of is what I've already mentioned, and that would seem to favour having a bare CPC.

Of course, at least now, Eire doesn't seem to like/'allow' over-sleeving at terminations, so maybe it's just that they didn't like the idea of G/Y sleeving at then ends?

Kind Regards, John

Nothing to do with reidentifying conductors, which has always been prohibited.

 

[Bigily87]

Hi DIYers!

I’ve recently been doing some DIY electrical work and have, of course used earth sleeve on my Twin + Earth cables.

But here’s something I’ve always wondered - why do they not just supply the cable with earth already sleeved? Three core flex has the earth wire sleeved, so why not T+E? Is there a reason for it?

Manufacturing 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