Earthing in new plastic sockets

brayleyboy

I hope somebody can help.

Over the weekend I have replaced some pretty old plastic plug sockets with some new plastic ones i bought at screwfix. The old double sockets had one terminal each for live/neutral/earth. Each terminal was wired up to the relevant wire from both the circuit cables (i.e. both live cables into live etc.) which is what i expected.

The new sockets still have one live/neutral terminal so I have wired these up in the same way. However the new socket has 2 earth terminals. At present I have just wired up both earth wires to one of the earth terminals, but should the earth from 1 circuit cable be wired up to one terminal, and the the earth from the other circuit cable to the other?

The question I have is, is it essential that I change it, and if so does it matter which earth goes to which terminal? Also there doesnt seem to be an earth cable attached to the metal back box, is this essential?

I have not yet replaced the fuse for the circuit with the sockets in, and would welcome some advice.

Many thanks

ormus

no it doesnt matter which one you use.
they supply 2 just for convenience. it maybe easier to use the left or right one.

brayleyboy

thats what I thought, its just on the small wiring diagram suppled with the socket they had one into each which i thought was odd.

I think I need to add some supplementary earthing to the back boxes but there are no terminals for this. Is it acceptable to use one of the spare loops for screwing on the old style faceplates (with 2 screws at top and bottom) instead.

ormus

it would prob be ok, but not sure if legal?
i would rather make a new terminal by drilling the box back plate and using a brass ba bolt and 3 nuts.
then reinstall/install the box into the wall.

robby-01

ormus wrote: »

no it doesnt matter which one you use.
they supply 2 just for convenience. it maybe easier to use the left or right one.

They are not put there for convienience at all.
If the sockets are being used to supply equipment with high protective conductor currents then each protective conductor(earth)should be terminated into a seperate terminal.
If the back box has 1 or more fixed lug then it does not require bonding.

ormus

aye, but in a domestic house?

robby-01

ormus wrote: »

aye, but in a domestic house?

No difference at all.

Nobleck

robby-01 wrote: »

They are not put there for convienience at all.
If the sockets are being used to supply equipment with high protective conductor currents then each protective conductor(earth)should be terminated into a seperate terminal.
If the back box has 1 or more fixed lug then it does not require bonding.

Computers in offices for example use dual earth connections in the sockets, for the very reason Robby has stated

uncle_buck_3

On the subject of earthing …can any of the electricians explain why earth sleeving is fitted onto the earth wire of twin & earth cables….surely you want as much of the earth conductor exposed as possible!

Nobleck

Earth sleeving is used to identify the earth conductor, it also helps to prevent the earth conductor from possible shorts on the Live or Neutral conductors.
Most Electricians that carry out Test and Inspections would also make a note about Earthing conductors not being sleeved in their report(thus recommending that they should be sleeved).
The only time you would want a lot of bare conductor would be when using an Earth Electrode(Stake) driving it deep into the ground to achieve a satisfactory Earth.
I don't think i've missed anything out, if i have you're welcome to expand on my comments.

brayleyboy

Thanks for all the replies, it has put my mind at rest (sort of!)

Can I just confirm something. The only things that will be plugged in are domestic appliances (TV/ PlayStation/ Hoover/ Hairdryer etc). Is it likely that any of this type of appliance have "high protective conductor currents" that would require me to wire the earth terminate each earth conductor into a separate terminal? I may plug a laptop in from time to time, would this make a difference?

The sockets dont have any adjustable lugs so I suppose technically I dont need to supplementary bond to the backboxes, but I may anyway just for good measure.