While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?
What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

In article ,
wrote:
While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?
What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

If a mouse can get at it, it is accessible. So use a junction box.

--
*The older you get, the better you realize you were.

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

On Thursday, 5 October 2017 10:59:25 UTC+1, wrote:
whether there is any convention when splicing twin+earth into twin (no
earth)?

Shouldn't be done. You have knowingly installed a length of cable with no working circuit protective conductor - even worse, you have installed a cable with a cpc and not connected it.

Either replace the whole run back to a proven working cpc, or as a mitigating measure pick up an earth from somewhere (preferably on the same circuit) and run it to the location in 10mm green/yellow.

What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

Cables should be clipped or clamped each side of the joint. Unless you have a handy joist to clip to, this suggests using an enclosure with strain relief.

Owain

On 05/10/2017 11:17, Dave Plowman (News) wrote:
In article ,
wrote:
While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?
What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

If a mouse can get at it, it is accessible. So use a junction box.

Why? I've always thought that crimps or/and soldering were the "weapon
of choice"

On 05/10/2017 11:37, wrote:
On Thursday, 5 October 2017 10:59:25 UTC+1, wrote:
whether there is any convention when splicing twin+earth into twin (no
earth)?

Shouldn't be done. You have knowingly installed a length of cable with no working circuit protective conductor.
The cable goes to a light switch - would you *really* have chased out
the wall to replace the whole cable?
I was surprised to find a cable without a CPC but I suspect it's one of
many in the lighting circuits. A re-wire is probably due in the future.
- even worse, you have installed a cable with a cpc and not connected it.
This is the bit I was unhappy about. The practical choice was to wrap
the damaged cable in self-amalgamating tape or replace the damaged section.

Either replace the whole run back to a proven working cpc, or as a mitigating measure pick up an earth from somewhere (preferably on the same circuit) and run it to the location in 10mm green/yellow.
10mm!
I've since found that the ceiling rose has an earth terminal connected
by T&E to the CU so I can connect my CPC to that.

What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

Cables should be clipped or clamped each side of the joint. Unless you have a handy joist to clip to, this suggests using an enclosure with strain relief.
They're clipped to a joist (unlike 99% of the wiring and the many tens
of JBs that are littered about between the joists)

Owain

In article ,
wrote:
On 05/10/2017 11:17, Dave Plowman (News) wrote:
In article ,
wrote:
While lifting some boards to install pipework we found a few cables
that had been nibbled, in one case they had exposed the neutral
conductor and several others where they'd gone through the outer PVC
to expose the red insulation. I've replaced the runs where possible
but had to splice-in a length of new cable (using crimps) when the
cable dropped into a plastered wall. These splices are half a metre
at the longest. In one case the new T&E went to the ceiling rose but
was spliced to a cable without an earth, in others the T&E is
inserted into a length of T. I cut the earth back in the rose but I
haven't encountered T(no E) before so it got me wondering whether
there is any convention when splicing twin+earth into twin (no
earth)? What's the jury's opinion of insulated crimps (with the
correct tool, and either covered with heat shrink or
self-amalgamating tape) for solid lighting wiring?

If a mouse can get at it, it is accessible. So use a junction box.

Why? I've always thought that crimps or/and soldering were the "weapon
of choice"

They might give some advantages if done properly using quality materials,
and skill. But far more chance of cocking it up than a JB. Crimps vary
wildly in quality. I've seen some made out of baking foil. And seen some
results of attempts to solder things.

--
*A clear conscience is usually the sign of a bad memory *

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

On Thursday, 5 October 2017 14:00:29 UTC+1, wrote:
Shouldn't be done. You have knowingly installed a length of cable
with no working circuit protective conductor.
The cable goes to a light switch - would you *really* have chased out
the wall to replace the whole cable?

If it's /just/ the switch drop, then that's actually fairly favourable, as you can connect T&E above the ceiling and prove continuity around the rest of the circuit.

The light switch should of course be a plastic one, and some would suggest using insulated screws or insulated caps over the screwheads, and there should be a label at the CU.

https://www.patlabelsonline.co.uk/he...h-labels-p1140

Owain

Should you firstly not try to stop the problem reoccurring ie exterminate
the mouse problem and stop them gaining access to the wiring?
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a plastered
wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in the
rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?
What's the jury's opinion of insulated crimps (with the correct tool, and
either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

I'm intrigued how old the twin with no earth might be also.
I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total rewire
jobs.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On 05/10/2017 11:17, Dave Plowman (News) wrote:
In article ,
wrote:
While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?
What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

If a mouse can get at it, it is accessible. So use a junction box.

Why? I've always thought that crimps or/and soldering were the "weapon of
choice"

In article ,
wrote:
On Thursday, 5 October 2017 10:59:25 UTC+1, wrote:
whether there is any convention when splicing twin+earth into twin (no
earth)?

Shouldn't be done. You have knowingly installed a length of cable with
no working circuit protective conductor - even worse, you have installed
a cable with a cpc and not connected it.

Are you certain repairing an existing installation that once conformed to
regs isn't allowed?

If you're worried about having an ECC on a short length of replaced cable,
simply pull it out.

--
*A nest isn't empty until all their stuff is out of the attic

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

On Thursday, 5 October 2017 17:04:00 UTC+1, Dave Plowman (News) wrote:
Are you certain repairing an existing installation that once conformed to
regs isn't allowed?

The original problem sounded worse than it actually is.

"once conformed to regs" is a red herring, as even bare wire on cleats once conformed to regs.

I would also coil up sufficient spare new T&E in the ceiling to allow the switch drop to be replaced at a future date without needing a join.

Owain

On 05/10/2017 16:40, Brian Gaff wrote:
Should you firstly not try to stop the problem reoccurring ie exterminate
the mouse problem and stop them gaining access to the wiring?
Brian


I'll try, but with a house like this I think that's going to be a
challenge, even without cats that seem to have "taken" to the country
life ;-)

On 05/10/2017 10:59, wrote:

While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?

Generally, unused cores should be tied to earth if possible. In cases
where that is not possible, then ideally they could be terminated in
some way to prevent them from being able to make accidental contact with
anything else. So terminating in a bit of chock block or in an insulated
butt crimp (with nothing in the other side) would meet the requirements.
Leaving a length of earth folded back in some earth sleeving is also
commonly done (although not totally compliant)

Any of those are seen as preferable to clipping the earth wire off tight
against the stripped outer since it means it could be brought into
service later if the circumstances changed.

What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

Insulated Crimps and heat shrink is acceptable in most cases.

http://wiki.diyfaq.org.uk/index.php/...ing#Heatshrink




--
Cheers,

John.

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

On 05/10/2017 16:38, wrote:
On Thursday, 5 October 2017 14:00:29 UTC+1, wrote:
Shouldn't be done. You have knowingly installed a length of cable
with no working circuit protective conductor.
The cable goes to a light switch - would you *really* have chased out
the wall to replace the whole cable?

If it's /just/ the switch drop, then that's actually fairly favourable, as you can connect T&E above the ceiling and prove continuity around the rest of the circuit.

The light switch should of course be a plastic one, and some would suggest using insulated screws or insulated caps over the screwheads, and there should be a label at the CU.

https://www.patlabelsonline.co.uk/he...h-labels-p1140

Owain


Thanks, I hadn't seen those labels before, unfortunate that they're sold
in packs of 100 - anybody want to buy 99 labels? ;-)
(I'll print a suitable label unless I find smaller quantities somewhere)

On 05/10/2017 18:11, John Rumm wrote:
On 05/10/2017 10:59, wrote:

While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?

Generally, unused cores should be tied to earth if possible. In cases
where that is not possible, then ideally they could be terminated in
some way to prevent them from being able to make accidental contact with
anything else. So terminating in a bit of chock block or in an insulated
butt crimp (with nothing in the other side) would meet the requirements.
Leaving a length of earth folded back in some earth sleeving is also
commonly done (although not totally compliant)

Any of those are seen as preferable to clipping the earth wire off tight
against the stripped outer since it means it could be brought into
service later if the circumstances changed.

What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

Insulated Crimps and heat shrink is acceptable in most cases.

http://wiki.diyfaq.org.uk/index.php/...ing#Heatshrink


If I find any more cables that have just had the outer insulation
nibbled I think I'll wrap them with self-amalgamating tape rather than
splicing-in a new piece of cable and sleeving with heat shrink. I wonder
whether mice prefer self amalgamating tape or PVC insulation ... ?

On 05/10/2017 21:13, wrote:
On 05/10/2017 18:11, John Rumm wrote:
On 05/10/2017 10:59, wrote:

While lifting some boards to install pipework we found a few cables that
had been nibbled, in one case they had exposed the neutral conductor and
several others where they'd gone through the outer PVC to expose the red
insulation. I've replaced the runs where possible but had to splice-in a
length of new cable (using crimps) when the cable dropped into a
plastered wall.
These splices are half a metre at the longest. In one case the new T&E
went to the ceiling rose but was spliced to a cable without an earth, in
others the T&E is inserted into a length of T. I cut the earth back in
the rose but I haven't encountered T(no E) before so it got me wondering
whether there is any convention when splicing twin+earth into twin (no
earth)?

Generally, unused cores should be tied to earth if possible. In cases
where that is not possible, then ideally they could be terminated in
some way to prevent them from being able to make accidental contact
with anything else. So terminating in a bit of chock block or in an
insulated butt crimp (with nothing in the other side) would meet the
requirements. Leaving a length of earth folded back in some earth
sleeving is also commonly done (although not totally compliant)

Any of those are seen as preferable to clipping the earth wire off
tight against the stripped outer since it means it could be brought
into service later if the circumstances changed.

What's the jury's opinion of insulated crimps (with the correct tool,
and either covered with heat shrink or self-amalgamating tape) for solid
lighting wiring?

Insulated Crimps and heat shrink is acceptable in most cases.

http://wiki.diyfaq.org.uk/index.php/...ing#Heatshrink


If I find any more cables that have just had the outer insulation
nibbled I think I'll wrap them with self-amalgamating tape rather than
splicing-in a new piece of cable and sleeving with heat shrink.

It has the advantage of working when there is no free end to thread
through the heat shrink!

I wonder
whether mice prefer self amalgamating tape or PVC insulation ... ?

That I don't know!


--
Cheers,

John.

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

On 05/10/2017 16:44, Brian Gaff wrote:

I'm intrigued how old the twin with no earth might be also.

On a lighting circuit, probably mid fifties to 1966 or slightly after.

I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total rewire
jobs.

Any work on a lighting circuit without an earth is going to be dodgy -
there is no way to do much with it to current standards.



--
Cheers,

John.

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

On 05/10/2017 21:37, John Rumm wrote:
On 05/10/2017 16:44, Brian Gaff wrote:

I'm intrigued how old the twin with no earth might be also.

On a lighting circuit, probably mid fifties to 1966 or slightly after.

* I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total
rewire
jobs.

Any work on a lighting circuit without an earth is going to be dodgy -
there is no way to do much with it to current standards.




The earth doesn't usually go to the fitting.
It doesn't really do much at all in the standard loop in system.

On 05/10/2017 16:54, Dave Plowman (News) wrote:
In article ,
wrote:
On Thursday, 5 October 2017 10:59:25 UTC+1, wrote:
whether there is any convention when splicing twin+earth into twin (no
earth)?

Shouldn't be done. You have knowingly installed a length of cable with
no working circuit protective conductor - even worse, you have installed
a cable with a cpc and not connected it.

Are you certain repairing an existing installation that once conformed to
regs isn't allowed?

The difficulty is that new work has to be to current standards, and this
one of those cases where you can't really do it. So its going to be a
bodge either way unless you rewire the circuit.

If you're worried about having an ECC on a short length of replaced cable,
simply pull it out.

Or label it as not connected on both ends.


--
Cheers,

John.

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

On Thursday, 5 October 2017 21:37:56 UTC+1, John Rumm wrote:
On 05/10/2017 16:44, Brian Gaff wrote:

I'm intrigued how old the twin with no earth might be also.

On a lighting circuit, probably mid fifties to 1966 or slightly after.

I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total rewire
jobs.

Any work on a lighting circuit without an earth is going to be dodgy -
there is no way to do much with it to current standards.



An RCD would be an effective way of gaining adequate safety for lighting circuits only, but it's not regs compliant so you can't do that.


NT

In article ,
Brian Gaff wrote:
I'm intrigued how old the twin with no earth might be also.

IIRC, it was somewhere in the '70s when the regs were changed to require
an earth on lighting circuits in new builds. It was common to see TW&E
used in lighting circuits with the earth simply lopped off.


I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total rewire
jobs.
Brian

--
*I'm already visualizing the duct tape over your mouth

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

In article . com,
dennis@home wrote:
On 05/10/2017 21:37, John Rumm wrote:
On 05/10/2017 16:44, Brian Gaff wrote:

I'm intrigued how old the twin with no earth might be also.

On a lighting circuit, probably mid fifties to 1966 or slightly after.

I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total
rewire
jobs.

Any work on a lighting circuit without an earth is going to be dodgy -
there is no way to do much with it to current standards.




The earth doesn't usually go to the fitting.

Depends on the fitting.

It doesn't really do much at all in the standard loop in system.

Metal plate switches have become popular, and they usually stipulate an
earth.

But with new wiring it's there if ever needed.

--
*How's my driving? Call 999*

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

On 05/10/2017 22:05, wrote:
On Thursday, 5 October 2017 21:37:56 UTC+1, John Rumm wrote:
On 05/10/2017 16:44, Brian Gaff wrote:

I'm intrigued how old the twin with no earth might be also.

On a lighting circuit, probably mid fifties to 1966 or slightly after.

I guess one could run separate earths, and actually many forms of join
should be fine in my humble opinion, but probably not exactly true to the
current specs Surely there has to be provision for repairs not total rewire
jobs.

Any work on a lighting circuit without an earth is going to be dodgy -
there is no way to do much with it to current standards.



An RCD would be an effective way of gaining adequate safety for lighting circuits only, but it's not regs compliant so you can't do that.

Its one of the "standard" mitigation options:

http://wiki.diyfaq.org.uk/index.php/...#Reducing_risk




--
Cheers,

John.

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

On 05/10/2017 23:56, Dave Plowman (News) wrote:
In article ,
Brian Gaff wrote:
I'm intrigued how old the twin with no earth might be also.

IIRC, it was somewhere in the '70s when the regs were changed to require
an earth on lighting circuits in new builds. It was common to see TW&E
used in lighting circuits with the earth simply lopped off.

1966 when the 14th edition was introduced... (although some installers
did not seem to get with the program until a few years later!)




--
Cheers,

John.

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

In article ,
John Rumm wrote:
On 05/10/2017 23:56, Dave Plowman (News) wrote:
In article ,
Brian Gaff wrote:
I'm intrigued how old the twin with no earth might be also.

IIRC, it was somewhere in the '70s when the regs were changed to
require an earth on lighting circuits in new builds. It was common to
see TW&E used in lighting circuits with the earth simply lopped off.

1966 when the 14th edition was introduced... (although some installers
did not seem to get with the program until a few years later!)

Ah - thanks John. Since PVC wiring was around then, there are likely still
quite a few houses around with no lighting earth - but the wiring
otherwise good.

--
*A cartoonist was found dead in his home. Details are sketchy.*

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

On 06/10/2017 00:34, Dave Plowman (News) wrote:
In article ,
.... snipped

1966 when the 14th edition was introduced... (although some installers
did not seem to get with the program until a few years later!)

Ah - thanks John. Since PVC wiring was around then, there are likely still
quite a few houses around with no lighting earth - but the wiring
otherwise good.

.... unless Jerry, Mickey, Minnie or (especially) "Danger" mouse have
paid a visit :-(

In article ,
wrote:
On 06/10/2017 00:34, Dave Plowman (News) wrote:
In article ,
... snipped

1966 when the 14th edition was introduced... (although some installers
did not seem to get with the program until a few years later!)

Ah - thanks John. Since PVC wiring was around then, there are likely
still quite a few houses around with no lighting earth - but the
wiring otherwise good.

... unless Jerry, Mickey, Minnie or (especially) "Danger" mouse have
paid a visit :-(

That can happen to a new installation too. Although I'd hope a house built
to decent standards would prevent rodent access to such areas.

--
*Jokes about German sausage are the wurst.*

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

On 05/10/2017 11:37, wrote:

Either replace the whole run back to a proven working cpc, or as a mitigating measure pick up an earth from somewhere (preferably on the same circuit) and run it to the location in 10mm green/yellow.

10mm earth?


--
Adam

On 06/10/2017 19:22, ARW wrote:
On 05/10/2017 11:37, wrote:

Either replace the whole run back to a proven working cpc, or as a
mitigating measure pick up an earth from somewhere (preferably on the
same circuit) and run it to the location in 10mm green/yellow.

10mm earth?

Perhaps it is armoured or has some other mechanical protection?

On 06/10/2017 10:56, Dave Plowman (News) wrote:
That can happen to a new installation too. Although I'd hope a house built
to decent standards would prevent rodent access to such areas.

We get mice in the loft every harvest time. Even with modern
construction it would be very hard to make a loft mouse proof. Most
houses (but not ours) have exposed lighting wires in the loft.

Andy