"Hamish" wrote in message
...
All the wiring in my new house is run in conduit which acts as the earth.

The conduit terminates in metal boxes approx 5"x"2.5" with the 15 amp
faceplate fixed by four screws in the corners.

Is it possible to buy adaptor plates for these old style boxes or do I
have
to replace them and ,if so, how should the earth connection be secured.

Also, is it permissible to run earth connections from the terminals in new
boxes to existing conduit runs fixed by an earthing strap?

TIA



You would be better running new cables through the system to give you more
scope in what you can connect. The old boxes you have should take a new
back box inside it and let you fit new sockets.

Using the conduit as an earth is not the ideal either. If there are any
breaks or loose fittings in the old installation, then the earth will
effectively be broken at these points. They may show good connection when
tested with a multi-meter, but if a short or other fault occurs, the break
may not be able to pass the load safely and blow the fuse.

If you can get to all the junction boxes and socket ends, then pull three
(red, black and green/yellow) new 2.5 mm PVC's through the old conduit to
make a new ring main for the sockets at least, and make sure that the earth
is properly bonded back the supply cable and into the fuse box (consumer
unit).


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