MisterP wrote:

This is a 50 year old installation with existing vertical steel oval
conduits to sockets plastered into the walls. The rubber(!) cable
enters from above and there is a grommet inserted into each of the
conduits to prevent damage to the cables.

Now if rewired with PVC sheathed cable, then
a) Can I re-use the steel conduit?

Yes - at least for switch drops. You may have difficulty getting
2x2.5mm^2 T&E through the socket runs, but then again it is possible
sometimes using the old cable to pull through the new. (strip the outer
insulation at the end of the old and new wires and firmly twist the
inners together before taping up. tape the second wire a couple of feet
back from the joint of the first and it will make pulling through a bit
simpler.

b) Where can I get suitable grommets? These are top hat shaped with
central hole for the cable.

Usually the existing ones stay put and remain serviceable.

c) The recessed steel boxes do not have an earth connection. Can one
be fitted or is it better to replace each box?

As long as they don't have two moveable screw holes then you can rely on
the screwed connection from the accessory to earth the box. Often older
installs like that will have odd sized backboxes, or wooden ones which
need replacing. Needless to say you probably want lots of sockets in
positions where there are currently none.



--
Cheers,

John.

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