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

"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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Hamish wrote:

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.


Umm. IIRC steel boxes have the right sized holes to take those old
conduits, if the thread is still present on the end, and useable..

There is a lot to be said for em. Fire in yer cables (not unusual with
the rubber insulated cables they use) did not set the local mouse
droppings, and house, on fire.

You CAN simply use em as earth, but heed BigWallops warnings.

IME, you can bodge the odd one if you know what you are doing, but if
its a complete overhaul, you would be better served by ripping out the
whole house wiring and redoing it with modern wiringts to modern
standards and putting in a new consumer unit.

The original cable insulation is likely to be well perished, and the
slightest disturbance may render it unservicable.

Re wire the lot, making as much mess as is needed, and get the plasterer
in afterwards, and redecorate.

THEN you can install all the things like TV and cat 5 cables, LV spots
and so on that will make it a far more useable and saleable house.

A house needs a major workover every 50 years. Time this one had it.







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

TIA

"The Natural Philosopher" wrote in message
...
....
IME, you can bodge the odd one if you know what you are doing, but if
its a complete overhaul, you would be better served by ripping out the
whole house wiring and redoing it with modern wiringts to modern
standards and putting in a new consumer unit.

Personally, I would re-use the main conduit runs where I could, even if I
were extending the system. It is really hard to put a nail through steel
conduit.

A house needs a major workover every 50 years. Time this one had it.

Or, in the case of electrics, a complete re-wire when the cable reaches the
end of its life. A 1950s house that still has 15A sockets is probably about
30 years overdue for its first re-wire.

Colin Bignell

In article ,
The Natural Philosopher wrote:
Umm. IIRC steel boxes have the right sized holes to take those old
conduits, if the thread is still present on the end, and useable..

50s conduit will be imperial, and I'm not sure where you'd get suitable
boxes or backing rings etc. Also, I'd guess the originals will be proper
conduit boxes where the conduit screws into a collar. They will be
impossible to remove without damage, IMHO.

--
*A closed mouth gathers no feet.*

Dave Plowman London SW 12
RIP Acorn

In article ,
Hamish wrote:
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?

I'm surprised you don't want extra sockets, or to re-locate the existing
ones.

IMHO, ignore the conduit as an earth, and run earth wires through it where
it's in suitable places to be re-used.

Remove the old boxes and replace with modern ones. What conduit you end up
re-using will then simply be a convenient and well protected run for
modern cable, but with no electrical function.. It might well save some
time for lighting switch drops.

--
*In "Casablanca", Humphrey Bogart never said "Play it again, Sam" *

Dave Plowman London SW 12
RIP Acorn