Earthing Socket

[aidy_is]

Brother in law is extending a ring to get more sockets in garage/conservatory. The existing ring is one of those which has no earth wire but instead a (round) metal conduit that is earthed.
The socket he was going to extend from looks like it has been replaced because it is a plastic one and has no discernable way of joining to the conduit.
question is, what is the best way of making sure this socket and the new ones are earthed?

Ta, @

 

[plugwash]

metal conduit should be earthed prefereablly at both ends and the easiest way to do this is with metalclad boxes

however it should not be relied apo as the only earth

also all wiring in a garage should be protected with some form of conduit and scokets in a garage should be metalclad for impact resistance

ok what to do...

pull or push an earth trhough the existing conduit (it's probablly easiest and best to replace all the cable in them at once with 3 new 2.5mm singles and replace any plastic sockets back with metalclad ones

for your new runs the ideal methods would be metal conduit or pyro but pvc conduit should be ok and is probablly easier for you to install again running 3 2.5mm singles in it conencting to metalclad fittings with proper conduit adaptors

 

[kendor]

I've always as good practice run an earth wire inside steel conduit and not just relied on the tube itself for a good earth but this is another area where the interpretation of the regs gave confusion and at one point it was acceptable to allow the tube to be an earth as long as it gave a sufficiently low enough reading when tested, I still disagreed when that interpretation came about as i felt that the screw joints could over time become high resistance and therefore a seperate earth was more likely to keep it's low resistance reading than relying on the conduit.
This was also the situation with bonding, where before all radiators would need bonding then the interpretation was no need if the reading was ok between all of the rads. When the agreed practice keeps changing it just leads to complete confusion.