Greensleeves was my delight

[The Medway Handyman]

Hi All

Of late I've done a fair amount of electrical work. Just replacing sockets, switches & light fittings (all within part p in case the safety police are listening).

I know that the earth wire on T&E should be sleeved with the green/yellow sleeving - although I've found a surprising number of installations where it was missing.

Because I know it should be there according to 'regs' I've always fitted it.

But what's the purpose? Identification? Insulation? Protection?

Wouldn't all of these functions be better served by insulating it (like the live & neutral) in the first place?

In short, why is the earth in flexible already insulated, but left as a bare cable in T&E?

Doesn't seem to make sense to me.

[nightjar]

It was not always required in the past.

Identificaton and preventing accidental shorts against terminals.

Cable is at greater risk from damage due to things like nails driven through it. Insulating the earth would reduce the chances of such damage creating a direct short to earth and thus increase the risk to the person driving the nail.

Colin Bignell

[Colin Wilson]

Perhaps a couple of reasons

a) cable construction - the flex might be a funny shape if all the cores were not insulated (i.e. lumpy or slightly oval rather than round)

b) its flexible - the insulation helps keep the strands where they should be, as against T&E where you only have the one conductor to worry about

[Dave Plowman (News)]

One valid reason is the main conductors are closer together reducing RFI.

[The Wanderer]

Going from memory, I think it was originally down to a combination of the Electricity Supply Regs and the IEE Wiring Regs many years ago. I'm sure someone who is more up to date than me will correct me if I'm wrong. :-)

Live and Neutral conductors were required to have insulation and protection, hence they are insulated and sheathed. The earth wire was only required to have protection, hence it is bare within the sheath.

As incidents - accidents - happened over the years, it was decided that the earth wire should be sleeved where it is not enclosed within the sheath, i.e. at plugs, switches etc.

As to why flexible cable has all cores insulated as well as sheathed, TBH, I don't know the answer, never needed to. I guess it's buried in the history of the two sets of Regs, one which was statutory, the not.[1]

[1] No longer the case since the introduction of Part P, and different legislation which has replaced the ESRs.

[meow2222]

Having seen one or 2 plugs where the earth was stripped right back to the sheath, or cable used, a bare earth wire would not normally be sleeved by an end user, and is a risk of contacting either the N pin or bare wire coming out of N pin. There is also risk of contacting the live if there are loose earth strands and the whole thing is messily wired. IOW consumers need it to avoid shorts, as some aint much cop at wiring plugs.

NT