N. Thornton wrote:

Right. If youre truly unable to do the work you could buy a reel of
flex and a few sockets and get yourself electricity to the rooms that
way. Crude, but if it were me I would not want to be running mains
down that old stuff, not for a minute.

I think this is a very sensible idea. It wouldn't take much to rig up
temporary sockets and lights, with exposed cabling. We did this with our
current house, and lived with it for several months. RCD everything, and
tape down cables (hint - lots of gaffer tape and cable ties required).

Then you can take your time rewiring.


--
Grunff

"N. Thornton" wrote in message
om...

snip

Right. If youre truly unable to do the work you could buy a reel of
flex and a few sockets and get yourself electricity to the rooms that
way. Crude, but if it were me I would not want to be running mains
down that old stuff, not for a minute. I think this would be much
better use of a couple of hours than trying to megger the
installation, when it cant have more than 1% chance of passing.

I completely concur, far better spending the time doing something to help a
hopeless case than messing around pointlessly with something that could end
in the *death* of a member of the family. It shouldn't take two people long
to run a temporary system, certainly no longer than a day I suspect,
neatness doesn't enter into it (what ever your sister says...) as and when
the sub-surface job is done later any hole in walls etc. can be made good
before any redecoration.


Even by 1930s standards an installation like this would be condemned.


I'm not sure about that, but certainly anytime post war.

On Wed, 25 Aug 2004 15:22:10 +0100, :::Jerry:::: wrote:

"N. Thornton" wrote in message
om...

snip


Even by 1930s standards an installation like this would be condemned.


I'm not sure about that, but certainly anytime post war.

The bit I cut up (up the thread a bit) was stamped "BRITISH INSULATED
CALLENDERS CABLES", and a quick google shows BICC was formed June 1945, so
it looks like lead sheath was still in use post WW2.

"wanderer" wrote in message
...

Butyl rubber was a common insulant within the electricity supply
industry 60 to 70 years ago, used for lead-in cables to properties.
Much has been replaced, although it still turns up in predominantly
rural locations.

Lead sheathed cable is now considered to be unsafe for electrical
installation work, and should be replaced ASAP.

I'd guess that at least third to a half of all the houses in the country
still have lead-sheathed paper or PBJ insulated service cables. The supply
industry doesn't seem to be in any hurry to replace them.

--
Andy

"Andy Wade" wrote in message
...
"wanderer" wrote in message
...

Butyl rubber was a common insulant within the electricity supply
industry 60 to 70 years ago, used for lead-in cables to properties.
Much has been replaced, although it still turns up in predominantly
rural locations.

Lead sheathed cable is now considered to be unsafe for electrical
installation work, and should be replaced ASAP.

I'd guess that at least third to a half of all the houses in the country
still have lead-sheathed paper or PBJ insulated service cables. The
supply
industry doesn't seem to be in any hurry to replace them.

--
Andy



someone else commented on such cables being replaced on the Sutton
streetlights last year. I guess the difference is if they blow up
underground they don't really do much damage, whereas in a house they can be
a real fire hazard. So no real drive (other than presumably leakage) to
replace those underground.
It is sounding like they are more common that I'd have thought given some of
the postings on this thread! not that this is a good thing of course!!
amazing they actually keep going this long, despite the obvious dangers.
Matt

In article ,
Andy Wade wrote:
I'd guess that at least third to a half of all the houses in the country
still have lead-sheathed paper or PBJ insulated service cables. The
supply industry doesn't seem to be in any hurry to replace them.

But the ends of these tend to be sealed?

--
*Real men don't waste their hormones growing hair

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

"Dave Plowman (News)" wrote in message
...

But the ends of these tend to be sealed?

Yes (hopefully). For street cables I think most failures are the result of
water getting in due to faulty sealing of joints or mechanical damage.

--
Andy

This discussion has been about lead wiring.

Another type of cable sometimes used c. 50 years ago for ring mains
consisted of a copper sheath, a ceramic insulator and then the live and
neutral leads inside that, cased I thinkk in rubber. The whole about
1/3 inch in diameter.
while lead cable was used for lighting in our house, this copper/ceramic
cable was used for the ringmain power crcuits in our old house. I think
it was installed in the late 50s for my parents.

What we saw by 2000 was increasing incidents of short circuits (via the
copper exterior) and blown fuses. Eventually whole circuits became
unusable. Regular slight movements, duw to floor boards & joists
flexing as people moved about, had caused the ceramic to crumble. then
maybe some damp penetrated and shorts were the result.

This was eventually one of the final things that led us to persuade
widowed mother in her late 80s that the house was no longer safe for
her, poor lady.
The week after a major furniture moving exercise which obiously
disturbed floor boards even more, the entire kitchen circuit packed up.

So in 2000 we took over and had to replace the lot immediately.

Of course if you have to live with it for a short while, the advice
about not disturbing it applies to this just as for the lead cables.

So, Matt, do you have any cable like that in your ring mains?

David H-S

"David H-S" wrote in message
...
This discussion has been about lead wiring.

Another type of cable sometimes used c. 50 years ago for ring mains
consisted of a copper sheath, a ceramic insulator and then the live and
neutral leads inside that, cased I thinkk in rubber. The whole about
1/3 inch in diameter.
snip

MICC cable ?

In article ,
David H-S writes:
This discussion has been about lead wiring.

Another type of cable sometimes used c. 50 years ago for ring mains
consisted of a copper sheath, a ceramic insulator and then the live and
neutral leads inside that, cased I thinkk in rubber. The whole about
1/3 inch in diameter.

I think you are describing MICC (Mineral Insulated Copper Covered)
cable, or Pyro to use one of the trade names.

while lead cable was used for lighting in our house, this copper/ceramic
cable was used for the ringmain power crcuits in our old house. I think
it was installed in the late 50s for my parents.

What we saw by 2000 was increasing incidents of short circuits (via the
copper exterior) and blown fuses. Eventually whole circuits became
unusable. Regular slight movements, duw to floor boards & joists
flexing as people moved about, had caused the ceramic to crumble. then
maybe some damp penetrated and shorts were the result.

It lasts forever providing the ends are sealed against any
moisture ingress and the copper sheath doesn't get punctured.
I guess frequent movement could cause work-hardening and eventual
fracture of the copper sheath.

The insulation is magnesium oxide, which is hygroscopic (will
absorb water from the air given the chance), hence the need to
make sure the cable ends are well made.

MICC will survive being heated up to just short of copper's
melting point, and you can hammer a piece almost flat and it
will still be fine (providing you don't puncture the sheath),
as the conductors and compressed magnesium oxide all deform
in exactly the same proportion. Indeed, the stuff is all
initially made much thicker, and taken down to the required
final thickness by running it through pressure rollers.
It is still used today in situations where any of its outstanding
physical properties are required, but it is expensive and
installing it is a rather more specialist task. This and its
tendancy to absorb water into the insulation are its weak
points. Also, it doesn't handle voltage spikes from inductive
load switching well -- this isn't an issue today, but it was a
problem when fluorescent lamps first started appearing and
fast-break switches were still around (which were required
for earlier DC circuits).

--
Andrew Gabriel

In article ,
David H-S wrote:
Another type of cable sometimes used c. 50 years ago for ring mains
consisted of a copper sheath, a ceramic insulator and then the live and
neutral leads inside that, cased I thinkk in rubber. The whole about
1/3 inch in diameter.
while lead cable was used for lighting in our house, this copper/ceramic
cable was used for the ringmain power crcuits in our old house. I think
it was installed in the late 50s for my parents.

What we saw by 2000 was increasing incidents of short circuits (via the
copper exterior) and blown fuses. Eventually whole circuits became
unusable. Regular slight movements, duw to floor boards & joists
flexing as people moved about, had caused the ceramic to crumble. then
maybe some damp penetrated and shorts were the result.

You've not understood MICC cable. The insulator is already a powder so
can't crumble.

If it was properly installed, it must have been damaged in some way and
let moisture in - that's the only thing that eventually kills it.

A totally different and longer lasting product than lead sheathed - and
indeed one which is still very much in use for hazardous applications.

--
*If at first you don't succeed, avoid skydiving.*

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