for identification...reg 514?

To stop the bare earth wire touching live parts in an enclosure, such as terminal screws.

Ages ago when ring final 13 Amp sockets were protected by 30 Amp. fuse wire, and R.C.D.s were not used, I came upon a socket where the unsleeved and uninsulated three strand tinned copper earth wire had come into contact with the live conductor/terminal of the socket. Yes it was called live back then. Live was red and neutral was black. I seem to remember that at least one if not two of the earth wire strands had completely burned through and were broken. Such was the power of a live to earth fault. P.V.C. earth sleeving would have prevented that incident.

The type of cable is shown above.

Z.

514.1.2

514.3.2

514.4.6 Bare conductors to be identified by various methods including sleeving.

Z.

Sparkingchip said:

To stop the bare earth wire touching live parts in an enclosure, such as terminal screws.

 Sparkingchip ... good point, what Regulation, or hazard/risk, is that intended to address (that's not already covered by other requirements such as protection against overcurrent, or ADS)?

If we always add sleeving, and I think we pretty much always do, it rather begs the question why we do not do as other countries and allow cables with insulation in the earth core already - as made for ~Ireland for example

Or TPS for Australia

If it existed, I for one would be inclined to specify it.

Mike

I don't think that we forbid it, but presumably insulating only the live conductors is cheaper.

An uninsulated earth conductor in twin and earth is probably more effective than an insulated one, if someone puts a nail through a T&E and it clips a live conductor it’s more likely to short out onto a bare CPC than an insulated one.

It is amazing how on a wall several metres wide someone can manage to hit a 2.5 mm conductor in a twin and earth cable with a nail putting a picture up.

514.3.2 Every core of a cable shall be identifiable at its terminations and preferably throughout its length.

Graham,

132.1(2) Proper functioning. A tripped R.C.D. or tripped M.C.B due to a C.P.C. to L short just will not do!

Z.