Harry Bloomfield wrote:
David Hansen presented the following explanation :
On Sun, 17 Dec 2006 13:54:53 GMT someone who may be Harry Bloomfield
wrote this:-

Apart from the fact that it would be unlikely to have been wired with
an earth, those which were provided with one were just bare copper
wire.

Or alternatively the earth connection was made via the screws from
the conduit.

... and the (likely) grip conduit joints will be so rusted that it
would no longer be safe to rely upon it for earthing purposes.

There is a problem with half a century old rubber wiring. Its often in
such bad condition than any disturbance is liable to cause shorts,
fusenpoppen, shock or fire. In short, leave it well alone. The solution
is most likely to open the existing fl light and connect it up there,
making sure you dont run the new wire past the hot choke.

There is also the question of earth, the new fitting should be earthed,
assuming its metal cased. To achieve this you can rewire your lighting
cct if it has no earth. Borrowing an earth from somewhere else is
sometimes done, but this is not regs compliant, and there are reasons
why, so you should not do it. In short theres not much chance of you
being able to do it to modern safety standards without rewiring. But if
you choose to do so anyway, at least dont disturb the old rubber
wiring, thats where the biggest danger lies.


NT