Essex electrics...
... my MiL lives close to the Ford plant in Dagenham and it's a pretty good guess that whoever lived in her house before she did worked in the factory there. How do I know this?

A few years ago we were replacing her kitchen. Nothing fancy - a few new units and a new cooker & hood. The kitchen was quite close to the fusebox so I suggested that while we were at it we may as well replace the cooker cable rather than join on a new bit to run it where it was now required - and just as well in fact.

When we came to take out the old wire, the insulation just crumbled in our hands to leave bare wire. It was a good thick conductor but the insulation was hopeless... in fact it looked just like the sort of cable you might get on a jump-lead (only very much longer) - as if it had only been made to take, let's say, 12 or 24v rather than 240v mains current.

Evidently, whoever put the cable in knew just enough to realise that high current required a thick cable and so had taken something high amp-rated from the plant (cooker cable being expensive). It was put in, it worked and it was forgotten but they had not thought that insulation designed to last a few years in a car and shield 12v might not be up to 20 years buried in plaster and taking 240v. I'm just glad we took it out before the place burned down as a result.
( Ugi , it's a game of give and cake, Thu 10 Mar 2011, 12:50, 2 replies)

This is likely rubber insulated cable.
It does this. It's - more or less - safe if left truly undisturbed - but moved at all, and it flakes off.
(speedevil, Thu 10 Mar 2011, 13:23, closed)

You would think so...
... but this wasn't opaque like rubber would be - it was more like polyethylene sheathing - sort of translucent.

Also odd to be rubber when everything else was in PVC and this appeared (from the fact that it had been put into a diagonal groove in the plaster) to have been bodged in after most of the rest.
( Ugi , it's a game of give and cake, Thu 10 Mar 2011, 14:32, closed)