I live on a development about 30 - 40 years old.
The electricity company are laying new cables to the little substations. It
is a twisted trio of red cables.
I am curious as to what may have triggered this: Age of the cables?
Inadequacy of the cables? If inadequacy how would the electicity supplier
know? By logging the loads?
Seems a costly job and we have had no powercuts

They hat to rewire our development (mid 1980s build) a few years ago
after repeated failures and mini explosions.

Apparently, the original installers were not familiar with a new style
of cabling introduced at the time resulting in poor quality joints.

Chris K


DerbyBorn wrote:
I live on a development about 30 - 40 years old.
The electricity company are laying new cables to the little substations. It
is a twisted trio of red cables.
I am curious as to what may have triggered this: Age of the cables?
Inadequacy of the cables? If inadequacy how would the electicity supplier
know? By logging the loads?
Seems a costly job and we have had no powercuts

Maybe they are getting ready for new builds somewhere.
Brian

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"DerbyBorn" wrote in message
2.236...
I live on a development about 30 - 40 years old.
The electricity company are laying new cables to the little substations.
It
is a twisted trio of red cables.
I am curious as to what may have triggered this: Age of the cables?
Inadequacy of the cables? If inadequacy how would the electicity supplier
know? By logging the loads?
Seems a costly job and we have had no powercuts

In article 6,
DerbyBorn writes:
I live on a development about 30 - 40 years old.
The electricity company are laying new cables to the little substations. It
is a twisted trio of red cables.
I am curious as to what may have triggered this: Age of the cables?
Inadequacy of the cables? If inadequacy how would the electicity supplier
know? By logging the loads?
Seems a costly job and we have had no powercuts

That sounds like the 11kV feed between substations. There are usually
several paths, so some are redundant, and you wouldn't necessarily
lose power if one failed, but left like that, redundancy is reduced.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
ChrisK wrote:
They hat to rewire our development (mid 1980s build) a few years ago
after repeated failures and mini explosions.

Apparently, the original installers were not familiar with a new style
of cabling introduced at the time resulting in poor quality joints.

Interesting. I've lived in this house since the 70s and the cabling into
it looked old then. Nor has the road been dug up to replace that running
down it. It may have had localised repairs, though. Which does make me
wonder what the life of this stuff is?

I rewired internally when moving in - and have suddenly realised that
wiring is now about as old as the lead covered stuff I replaced. ;-)

--
*If you must choose between two evils, pick the one you've never tried before

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

On 13/04/2018 00:27, Dave Plowman (News) wrote:
In article ,
ChrisK wrote:
They hat to rewire our development (mid 1980s build) a few years ago
after repeated failures and mini explosions.

Apparently, the original installers were not familiar with a new style
of cabling introduced at the time resulting in poor quality joints.

Interesting. I've lived in this house since the 70s and the cabling into
it looked old then. Nor has the road been dug up to replace that running
down it. It may have had localised repairs, though. Which does make me
wonder what the life of this stuff is?

I rewired internally when moving in - and have suddenly realised that
wiring is now about as old as the lead covered stuff I replaced. ;-)


As to the life of PVC, the answer is of course that it all depends. It's
easy to see by experiment that it hardens and becomes brittle at ~80C,
just as we know that "old" natural rubber will be after a few decades at
ambient temperature. But actually, if that is lead covered and not
significantly disturbed, it will keep working.

For industrial purposes people tend to talk about PE, ABS, PVC etc
having a life in excess of 30 years at temperatures below about 50C. I
investigated a failure on a power station some years ago on some water
circuits which were plumbed in solvent weld pipe from 3" to 8" in a
mixture of ABS and PVC (each "run" was just one material). Over the
years they had replaced some of it with stainless because of failures
(including mechanical damage). The failed pipe had a brittle failure
associated with the axial join left by the spider which was used in the
extrusion process, but tests showed that it wasn't obviously any more
brittle than new material. It had done about 40 years at temperatures of
20 to 30 C. IIRC the claimed life was 30 years (but of course that was
really only a guess as these were new products with no history when they
were put in).

I played what I think of as one of my new CDs the other day, and then worked out it was 20!