Wed, 09 Sep 2026 17:53:31 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227263#Comment_227263 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227263#Comment_227263 Fri, 17 Jul 2015 23:02:59 +0100 tony
This is a physical process, not a chemical reaction.

We need evidence that it causes a problem, to date there is none

Loads of pic cables have been laid touching polystyrene, I have seen some.

There clearly is not a real problem or we would have these all over the world.

As the plasticiser in the cable migrates into the eps, the eps shrinks back and in the vast majority of cases no longer remains in contact and deplastisation ceases.

It would require a lot of effort to deplasticise a pic cable enough to make it brittle, it would not happen in the real world

Any budding researchers reading this?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227264#Comment_227264 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227264#Comment_227264 Fri, 17 Jul 2015 23:06:02 +0100 Paul in Montreal
The conductors are insulated in PVC, but the sheaths are not - plus we get different colours that tell you the current ratings in a nice visual way :)

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227265#Comment_227265 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227265#Comment_227265 Fri, 17 Jul 2015 23:27:12 +0100 Ed Davies
http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1521

I did a search before about this and didn't come up with any specific stories about it actually happening (really expected to see some horror pictures). However this, from a New Zealand cable manufacturer, seems pretty clear:

http://www.generalcable.co.nz/getattachment/0ebda90b-b4f8-43ae-b622-c9280295116b/PVC-Cables-in-Contact-with-Polystyrene-or-Bitumen.aspx

“Commonly used PVC plasticisers tend to exhibit solubility in polystyrene and polyurethane insulating
materials, …”

“The migration process would be expected to occur over a relatively long time frame, there is anecdotal evidence that rapid migration can occur in polystyrene block houses, portable buildings and chillers. This is due mainly to the large contact area between the insulating material and the cable.

The service life of PVC insulated and sheathed cables in the above situation are dependent upon the conditions of exposure and many years may elapse before noticeable deterioration of the PVC occurs. However, cable lifetime could be significantly effected [sic].”]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227268#Comment_227268 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227268#Comment_227268 Sat, 18 Jul 2015 08:00:31 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227269#Comment_227269 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227269#Comment_227269 Sat, 18 Jul 2015 08:05:31 +0100 fostertom https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227290#Comment_227290 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227290#Comment_227290 Sat, 18 Jul 2015 16:29:26 +0100 Ed Davies Posted By: tonyAre they saying no evidence or no problem as the timescale is long?No, I think they're saying there is a potential problem and that there's anecdotal evidence that it can, in some circumstances, be quite rapid. Though I tried to extract the important bits I'd suggest reading the whole thing, it's not long.

News, to me, was the possibility of problems with polyurethane and bituminsed building paper.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227291#Comment_227291 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227291#Comment_227291 Sat, 18 Jul 2015 16:33:56 +0100 Nick Parsons https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227294#Comment_227294 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227294#Comment_227294 Sat, 18 Jul 2015 17:43:05 +0100 owlman https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227299#Comment_227299 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227299#Comment_227299 Sat, 18 Jul 2015 18:42:41 +0100 Nick Parsons https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227366#Comment_227366 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13529&Focus=227366#Comment_227366 Mon, 20 Jul 2015 10:32:05 +0100 barney
Most cables (today) either have a modified plasticiser or are cross linked polyethylene - so it's not an ongoing issue - but temperature is a trigger for damage

Derating of cables when surounded by any thermal insulation is a different matter - that applies to any insulation type

Common sense says do not put the cables in the insulation zone - use a service void

Regards

Barney]]>