I know this happens but this is the first time I've seen it

[Lip.82]

I came across this today. Does anyone know how long it takes to totally destroy a cable?

 

[Richard Burns]

The sheath will just become more brittle over time; if it is not moved then it should be OK. Obviously it is not a good thing in general.

 

[westward10]

I think the "wet" part you are showing is from the insulation tape. The age and make up of the cable will be a factor as older cables contained plastisizer to make the sheath more flexible and it is this which causes migration.

 

[Taylortwocities]

I’ve seen polystyrene nibble into a pvc sheath a bit, but never had a fault as a result.
Polystyrene is a decent insulator so, as above, all should be ok if not disturbed.

 

[ruston]

I agree , I have seen it too, but the cable was fine .

 

[PEG]

Got the wrong idea on this title...thought it was a relationship query...

 

[SparkySy]

I remember going to an aquatics shop years ago that was having tripping problems, I assumed it was an rcd that was tripping but when I got there and they showed me it was an mcb. After having a look round I soon found the issue, the tanks were insulated with polystyrene and the wire was run on it but now was in the poly with no sheath or insulation! The wire had gone through it like a cheese wire and all 3 conductors were perfectly separate from each other until a tank they had been emptying where the 3 had shorted and left a massive black scorch mark and melted a huge crater! Ender up having to totally rewire the whole tank lighting properly. Must of taken out about 200m of ready to tat in copper out!!