Polystyrene and PVC wiring

[Cicero]

How long will it take for PVC wiring to be seriously affected by contact with polystyrene insulation?

Tia,

Cic.

[T i m]

I'd also like to know the answer to that ;-)

I was fixing the drooping roof lining to Mum / Dad's static caravan and apart from finding an empty mastic tube in the roof space I found a bit of T&E that had eaten it's way into the polystyrene?

I pulled them apart and the T&E 'seemed' ok but could it be contamninated?

All the best ..

T i m

[Andrew Gabriel]

Other way round -- the plasticiser will have left the PVC and gone into the polystyrene. It makes the PVC harder, and more likely to crack if bent. Having said that, I've never found a case where it's taken enough of the plasticiser out to make a noticable difference.

[Matt Beard]

Sounds like the T&E had got rather warm and sunk into the now soft polystyrene. If there is any chance this could be the case I recommend that you check the circuit protection rating.

Matt

[the q]

polystyrene bubbles. Stored in admitedly hot conditions (50C) the bubbles had melted to a horrible gunge before I openned them at 5 Years

The Q

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[Andrew Gabriel]

No heat is required for PVC to appear to 'melt' into polystyrene.

[Matt Beard]

That's scary; it suggests there is chemistry going on - although we know there is some where the plasticiser migrates into the polystyrene, but maybe even more is involved. Sounds like more reason to keep the two apart.

Matt

[Ian Stirling]

Polystyrene isn't very strong. In foam form, it's a thin net of bubbles held together by the strength of the walls. If you plasticise the walls then it just collapses.