Silicon sealing Ask questions and find answers to many subjects relating to electrics and electrical work

[hamish72]

I wish to seal some metal conduit entries through which twin and earth cables pass has silicon sealant any detrimental effects on pvc twin and earth outer sheath or any other suggestions please

[ericmark]

There are problems with leaching of plasticizer with polystyrene and silicon sealant comes as many types some which would cause problems, and which are OK I don't know. I would use fire stop or re-enterable compound. Of course heat is also a problem if it goes for any length. I have not seen any problems using silicon sealant but I would tend to use moisture drying type.

[chris_on_tour2002]

silicone should not adversely react with the pvc conduit - its used all the time on pvc windows, bathroom fittings etc with no detrimental affects as far as i am aware.

whether or not it will react and cause damage to the twin and earth cable i don't know. is the sheathing rubber or pvc?

with regard to heat there are heat and fire resistant silicones out there. though whether or not these would be safe to use on pvc/electrical cables i don't know.

you could always ring the technical helpline number and ask what uses the silicone is and is not suitable for. these helplines are usually quite... well, helpful.