Hi, I'm having a major headache.

I live in a 60's built maisonette, and have discovered that none of the
upstairs sockets are grounded. I was replacing a couple of socket
plates a while ago, and noticed there were only two wires (RED & BLACK)
connected to the appropriate terminals within the socket, but no earth
wire. The red&black wires disappear down a conduit pipe which appears
to be metal. Downstairs however all seems fine and the electricity
meter & fuse box are both grounded from the outside.

Is this sort of thing easily sorted or are we talking major rewiring
(and expense)? Would stuff have to be ripped out of walls?

Any help would be really appreciated.

Bart

In article .com,
Korgi wrote:
I live in a 60's built maisonette, and have discovered that none of the
upstairs sockets are grounded. I was replacing a couple of socket
plates a while ago, and noticed there were only two wires (RED & BLACK)
connected to the appropriate terminals within the socket, but no earth
wire. The red&black wires disappear down a conduit pipe which appears
to be metal. Downstairs however all seems fine and the electricity
meter & fuse box are both grounded from the outside.

In the '60s there was a requirement for three pin sockets to be earthed.
It's likely the steel conduit is providing the earth. However, this
depends on the socket being securely fixed to the box as the screws etc
are the earth path. I'd be inclined to supplement this with an earth
terminal fitted to the backing box with a tail from that to the socket
terminal.

Is this sort of thing easily sorted or are we talking major rewiring
(and expense)? Would stuff have to be ripped out of walls?

Any help would be really appreciated.

--
*Growing old is inevitable, growing up is optional

Dave Plowman London SW
To e-mail, change noise into sound.

On 27 Jan 2006 03:29:48 -0800 someone who may be "Korgi"
wrote this:-

I live in a 60's built maisonette, and have discovered that none of the
upstairs sockets are grounded.

Have you tested them, or do you just think this?

I was replacing a couple of socket
plates a while ago, and noticed there were only two wires (RED & BLACK)
connected to the appropriate terminals within the socket, but no earth
wire. The red&black wires disappear down a conduit pipe which appears
to be metal.

The conduit is undoubtedly also the protective conductor (earth).

The first thing I would do is get/borrow a socket tester and plug it
in to each socket. These testers don't do a thorough test, but do
give a good indication.

The second thing I would do is connect a short length of green and
yellow insulated wire from the earth terminal of the socket to the
terminal there should be in the box. This guards against the screws,
which are the protective conductor, becoming loose or falling out.

The third thing I would do/have done is a proper electrical test on
the wiring. This will thoroughly test the soundness of the conduit,
amongst other things. What work, if any, needs to be done depends on
the results of this test. It may be that no more work needs to be
done, other than a test in some years time. This can be a difficult
area. Some people doing such tests will recommend all sorts of
unnecessary work, simply in the hope that they can boost their
profits.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Cheers for the advice - I actually stumbled on this issue by accident,
when I noticed unusually loud "humming" sound coming from a guitar
pickup connected to a tape recorder in the upstairs bedroom. Having
read up about "ground loops", I thought I'd try connecting the outer
metal casing of the recorder to a mains water pipe in the adjacent
bathroom, and.... the hum had disappeared. I then plugged the said
recorder into an extension cord connected to a downstairs socket, and
again to my delight, no hum. So I tried all the sockets in the flat
that way and found that all the upstairs sockets were noisy, and all
the downstairs ones were silent.

Bart.

On 27 Jan 2006 06:01:26 -0800 someone who may be "Korgi"
wrote this:-

So I tried all the sockets in the flat
that way and found that all the upstairs sockets were noisy, and all
the downstairs ones were silent.

Then I suggest you get the socket tester rapidly and see what it
shows, then a full test. It may be that a joint has failed/is
failing in the conduit going upstairs.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On 27 Jan 2006 06:01:26 -0800 someone who may be "Korgi"
wrote this:-

So I tried all the sockets in the flat
that way and found that all the upstairs sockets were noisy, and all
the downstairs ones were silent.

I suspect this wireing is very old and could be getting near to the end
of it's useful life.

I'd suggest getting an independant electrician to do a periodic
inspection of the wiring. Don't go with your local elec supply
company, they'll more than likely just send a salesman round.

"Korgi" wrote in message
oups.com...
Cheers for the advice - I actually stumbled on this issue by accident,
when I noticed unusually loud "humming" sound coming from a guitar
pickup connected to a tape recorder in the upstairs bedroom. Having
read up about "ground loops", I thought I'd try connecting the outer
metal casing of the recorder to a mains water pipe in the adjacent
bathroom, and.... the hum had disappeared. I then plugged the said
recorder into an extension cord connected to a downstairs socket, and
again to my delight, no hum. So I tried all the sockets in the flat
that way and found that all the upstairs sockets were noisy, and all
the downstairs ones were silent.

Bart.

U might as well check format and wiring practice of all downstairs outlets,
too. Essentially, the conduits of both floors should be bonded as one steel
network, and a necessary link between storeys is adrift.
How many 13A sockets are u talking about? Are they single- or double-ganged?
Are they all routed in conduit runs? Are they at present connected by two
pairs of red and black wires of at least 20A gauge (which would indicate a
Ring mains pattern)?
Or is there just a pair of wires in each conduit run, implying spurs taken
off a major cct? If the latter style, naughty - there may well be overload
problems.
If there is no functional Earth present throughout when you plugged in tape
recorder upstairs, the integrity of -each- conduit and backbox appearance
(and of any hidden metal junction boxes) needs to be tested rigorously all
the way from supply E in Fuse Box! Are those fuse wires of correct gauge
(ie, not botched)?
As a previous person gas written, assuming each conduit continuity -has
been- proven sound, u should add 8" of green/yellow, stranded 20A wire from
back box brass terminal and the earth terminal of power outlet.
Jim

In article .com,
Korgi wrote:
So I tried all the sockets in the flat
that way and found that all the upstairs sockets were noisy, and all
the downstairs ones were silent.

It could be the earth connection to the conduit has failed - or the
conduit has been cut into to add sockets, etc. But this needs proper
checking either way. If, for example, the earth to the conduit is missing,
a faulty appliance could result in *other* things on that circuit becoming
live and dangerous - ie worse than no earths at all on individual sockets.

--
*Never underestimate the power of stupid people in large groups.

Dave Plowman London SW
To e-mail, change noise into sound.

"Korgi" wrote in message
oups.com...
Hi, I'm having a major headache.

I live in a 60's built maisonette, and have discovered that none of the
upstairs sockets are grounded. I was replacing a couple of socket
plates a while ago, and noticed there were only two wires (RED & BLACK)
connected to the appropriate terminals within the socket, but no earth
wire. The red&black wires disappear down a conduit pipe which appears
to be metal. Downstairs however all seems fine and the electricity
meter & fuse box are both grounded from the outside.

Is this sort of thing easily sorted or are we talking major rewiring
(and expense)? Would stuff have to be ripped out of walls?

If it was built in the 1960s and still uses the conduit as an earth, the
chances are that the wiring is original. If so, it is time it was all
replaced anyway.

Colin Bignell

In article ,
nightjar nightjar@insert my surname here.uk.com wrote:
If it was built in the 1960s and still uses the conduit as an earth, the
chances are that the wiring is original. If so, it is time it was all
replaced anyway.

It could well be PVC and still in good condition - although of course
there are other reasons to re-wire. If it's rubber I'd agree.

--
*Pride is what we have. Vanity is what others have.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
"nightjar" nightjar@insert my surname here.uk.com writes:

If it was built in the 1960s and still uses the conduit as an earth, the
chances are that the wiring is original. If so, it is time it was all
replaced anyway.

60's PVC should be fine. The earth fault loop impedance needs
testing. If it was a LA build, the screwed conduit would have
had to have painted threads, which will have prevented corrosion
over the years and resistance should still be low. As someone
else said, the earth continuity could have been damaged by
subsequent modifications though.

The wiring accessories (switches, sockets, fusebox, etc) in a
60's installation should be considered to be in need of a good
inspection though. Many of these will be at the end of their
life, but that's a relatively easy thing to fix. The other
issue could be lack of sockets (again, a LA build specified
many more than private builds would have had at that time).

--
Andrew Gabriel

"Andrew Gabriel" wrote in message
.. .
In article ,
"nightjar" nightjar@insert my surname here.uk.com writes:

If it was built in the 1960s and still uses the conduit as an earth, the
chances are that the wiring is original. If so, it is time it was all
replaced anyway.

60's PVC should be fine. ...

Agreed, but IME two wire and conduit is most often rubber.

Colin Bignell