Hey Folks,

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

Previously, I would have connected all three earth wires into the
socket. However, this unexpected configuration seems less likely to
come adrift because the three-wire collection goes into a fixed
connector and only a single wire goes to the socket. The three-wire
collection only needs disturbing if re-wiring is needed, not whenever
a socket is replaced.

(I recently bought a socket from Wickes; it had a square hole for the
earths and I had difficulty getting three thin earths to stay in. I
dislike bending the ends as they fall off if you have to straighten
them out.)

Apart from the sheathing, is the unexpected configuration: legal, less
safe, more safe?

TIA

Peter

On Wed, 10 Oct 2007 13:35:31 -0700, wrote:

Hey Folks,

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

That's probably why he was ex-electricity board...

--
Frank Erskine

That's probably why he was ex-electricity board...

cough ever wired sockets in a substation ?

AFAIK we couldn't actually book sleeving out, but the supply side
isn't covered under the 16th

It would seem a little "enthusiastic" to be fair, when you consider
you had live open busbars on the LV board :-}

wrote:

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

There was a time when sheathing for the earth was not required - your
installation may pre-date that.

Previously, I would have connected all three earth wires into the
socket. However, this unexpected configuration seems less likely to
come adrift because the three-wire collection goes into a fixed
connector and only a single wire goes to the socket. The three-wire
collection only needs disturbing if re-wiring is needed, not whenever
a socket is replaced.

It will have a very slight negative effect on the earth fault loop
impedance - but not enough to worry about.

The main difficulty of doing it that way is often the backbox terminals
doe snot have much capacity and will not as easily take as many wires.

(I recently bought a socket from Wickes; it had a square hole for the
earths and I had difficulty getting three thin earths to stay in. I
dislike bending the ends as they fall off if you have to straighten
them out.)

If you get a socket with decent square terminals like the TLC ultimate
one, then they are really nice to wire - plenty of terminal space and a
good grip.

Apart from the sheathing, is the unexpected configuration: legal, less
safe, more safe?

ok, very slightly less safe, but negligible - especially on an RCD
protected circuit.

(this assumes modern 2.5mm^2 cable with 1.5mm^2 CPC. If it is older
standard cable with only a 1.0mm^2 CPC then it is less desirable).


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.

Such people re-wire their own homes in one of two ways:

1. With absolute perfection that they've learned from years of
experience; or

2. Cutting every corner that they've learned from years of experience.

Commiserations - I used to live in a Type 2 house too.



--
Ian White

wrote in message
ps.com...
Hey Folks,

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

Previously, I would have connected all three earth wires into the
socket. However, this unexpected configuration seems less likely to
come adrift because the three-wire collection goes into a fixed
connector and only a single wire goes to the socket. The three-wire
collection only needs disturbing if re-wiring is needed, not whenever
a socket is replaced.

(I recently bought a socket from Wickes; it had a square hole for the
earths and I had difficulty getting three thin earths to stay in. I
dislike bending the ends as they fall off if you have to straighten
them out.)

Apart from the sheathing, is the unexpected configuration: legal, less
safe, more safe?

Some of the junction boxes in my house have a similar approach - the earth
wires are all twisted together external to the junction box and unsheathed.
AFAIK there was also an earth into the junction box, but there was more
space and less tangle inside with only one earth instead of one from each
T&E.

Now if the majority of the earth wires are external there may be no need of
sheathing but I would have thought that wires internal to a box would need
sheathing, because there is always a chance that one of them could come into
contact with a live or neutral teminal as the socket was positioned during
fitting or removal.

Still, it seems that it may have been common practice at one time.

Cheers

Dave R

P.S. which part of the country is this house in?

My house is in Berkshire and they do things differently from the way they
are done in Suffolk (small things like the way pipes are fixed to walls
etc.).

It would seem a little "enthusiastic" to be fair, when you consider
you had live open busbars on the LV board :-}
More reason to sleeve, as they could touch the bars.

LOL they could touch any phase or neutral more easily by going
straight for the busbars - and if it's a standard 500kVA sub, many
transformers are connected to the ACB via uninsulated overhead bars.

If they're already in the sub, they're at more risk from the other
exposed extraneous metalwork, than by having to take a screwdriver to
a socket to put themselves at risk.

That's completely ignoring the possibility of them playing with the HV
side of things !

wrote in message
ps.com...
Hey Folks,

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.

Which means nothing! 20+ years ago people did things differently.

I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!


Why would that matter? The socket usually stays where it is.

Previously, I would have connected all three earth wires into the
socket. However, this unexpected configuration seems less likely to
come adrift because the three-wire collection goes into a fixed
connector and only a single wire goes to the socket. The three-wire
collection only needs disturbing if re-wiring is needed, not whenever
a socket is replaced.

More sensible doing it that way.

(I recently bought a socket from Wickes; it had a square hole for the
earths and I had difficulty getting three thin earths to stay in. I
dislike bending the ends as they fall off if you have to straighten
them out.)

Apart from the sheathing, is the unexpected configuration: legal, less
safe, more safe?

TIA

Peter

Legal with respect to which Law? People often use the word "legal" when
they mean complying with an advisory regulation. This is not correct as
"legal" would refer to criminal law.
Sheathing doesn't matter inside the box on the back of a socket or a
switch - why would it?
I would connect the earth wires as you describe, but not all sockets are
good quality - so if you tighten the wires the screw keeps turning.

In article om,
wrote:
I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

I'm not sure when sleeving became mandatory but it was much longer than 20
years ago. I'd say more like 40. I've seen the 7/0.29 imperial ring main
cable - which 2.5mm metric replaced in about '70 - with sleeved earths.

Twisted earths - if over a long enough length - will give a perfectly
satisfactory connection provided the conductors aren't strained enough to
fracture. And a short tail from that to the fitting will not introduce a
high enough resistance to cause a fail. But it's not modern best practice.
Incidentally this was the way telephone cables were connected underground
once - dunno if they still are.

--
*When the going gets tough, the tough take a coffee break *

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

On Wed, 10 Oct 2007 13:35:31 -0700
wrote:

Hey Folks,

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

Not quite as bad as my lighting circuit (since replaced) which had
free-hanging junction boxes all over the place all wired with just the
phase and neutrals in the box, and all the CPC's taken, bare, but long,
under the box and just twisted together. After 30 years of people
trampling about in the loft (it's a bungalow, all the wiring is in the
loft), you can imagine what the impedance was.

R.

wrote in message
ps.com...
Hey Folks,

I recently had to replace a ring main socket in a part of the house
that was re-wired 20+ years ago by an ex-electricity board inspector.
I was surprised to see that the earth connectors, instead of being
wired into the socket, were twisted together along with a flying earth
and connected to the earth connector in the metal box. The flying
earth alone went to the socket. None of the earths were sheathed!

I recall sheathing for earths being introduced, which would probably have
been about 30 years ago. Wiring the earths to the backbox terminal used to
be done to ensure that the earth circuit was less likely to be damaged when
the final fit was to take place, usually in a new build, after other trades
had been working in the area. Modern backboxes have fairly small capacity
terminals, which would make that difficlut to do.

Colin Bignell

On Wed, 10 Oct 2007 13:35:31 -0700, p.scott wrote:

Hey Folks,

I recently had to replace a ring main socket in a part of the house that
was re-wired 20+ years ago by an ex-electricity board inspector. I was
surprised to see that the earth connectors, instead of being wired into
the socket, were twisted together along with a flying earth and
connected to the earth connector in the metal box. The flying earth
alone went to the socket. None of the earths were sheathed!

Previously, I would have connected all three earth wires into the
socket. However, this unexpected configuration seems less likely to come
adrift because the three-wire collection goes into a fixed connector and
only a single wire goes to the socket. The three-wire collection only
needs disturbing if re-wiring is needed, not whenever a socket is
replaced.



That looks like a pretty well wired socket. You don't break the earth on
the ring while replacing a socket and the box has to be earthed anyway if
it's metal. It's actually how I was trained to wire sockets (by Norweb)
30-odd years ago. :-) The earth wires should really be sleeved though,
but this was often omitted if there was no chance of them touching live
or neutral connections on the back of the socket (it's mainly an
identification issue). You probably found that the ring earths were wired
first, at the back of the box.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info http://mixpix.batcave.net

"mick" wrote in message
k...
On Wed, 10 Oct 2007 13:35:31 -0700, p.scott wrote:

Hey Folks,

I recently had to replace a ring main socket in a part of the house that
was re-wired 20+ years ago by an ex-electricity board inspector. I was
surprised to see that the earth connectors, instead of being wired into
the socket, were twisted together along with a flying earth and
connected to the earth connector in the metal box. The flying earth
alone went to the socket. None of the earths were sheathed!

Previously, I would have connected all three earth wires into the
socket. However, this unexpected configuration seems less likely to come
adrift because the three-wire collection goes into a fixed connector and
only a single wire goes to the socket. The three-wire collection only
needs disturbing if re-wiring is needed, not whenever a socket is
replaced.



Some 30 years ago I was taught to wire the earths to the socket (sheathed)
and a single piece of insulated earth wire to the connector on the metal
box. The reason given for this was that without the connection to the back
box the only way the box was earthed was through the screws holding the
socket and needed to be 'bonded' in case the socket was unscrewed whilst it
was live. Mind you this was at the time when councils were specifying earth
bonding to metal window frames.

Tony

On Thu, 11 Oct 2007 09:46:58 +0100 someone who may be "TMC"
wrote this:-

Some 30 years ago I was taught to wire the earths to the socket (sheathed)
and a single piece of insulated earth wire to the connector on the metal
box.

That is sensible.

The reason given for this was that without the connection to the back
box the only way the box was earthed was through the screws holding the
socket and needed to be 'bonded' in case the socket was unscrewed whilst it
was live.

The Wiring Regulations don't require this except, if as has already
been mentioned, conduit is providing the CPC.

A better reason for doing it this way is that failure of the single
conductor leaves just the back box unearthed (or to be precise
subject to the vagaries of any screws).

Mind you this was at the time when councils were specifying earth
bonding to metal window frames.

Why councils should specify such things is beyond me. They know
little about electricity and it wasn't required in the Wiring
Regulations. What seemed to be common was a misreading of the
wording. There were several tests about whether an item should be
bonded and it was only if ALL of them were met that it should be
bonded. Almost any bit of metal would meet one or two of the tests,
but that didn't mean it should have been bonded.


--
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

cough ever wired sockets in a substation ?
I hope you're not suggesting they wired the kettle in with croc clips...

No, but a 3kW cooker-element fan heater had them :-p

On 10 Oct, 22:06, Frank Erskine wrote:

That's probably why he was ex-electricity board...

Nice one! I should have said retired.

P