Cable in 25mm service void below insulation

23 Jun 2006
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United Kingdom
Chaps, I have a vaulted ceiling that has 100mm celotex between the rafters and then 50mm below it with all joints taped with foil tape.

This has been counter battened with a 25mm batten and the plasterboard has then been fixed to the batten. This leaves a 25mm void between the insulation and plasterboard.

There is an 11kW induction hob going in and I am looking to change the planned position for this. From what I can see the ideal most direct cable route to the new location would be in this void.

The chaps have already run in a 10mm² feed to the old hob location.

If I go ahead with the move is it likely they would use the void to run the cable or is it too close to the insulation?

If it is ok would it be ok for the cable to rest on the plasterboard or do i need to take the ceiling down tomorrow so they could get some clips in there to support the cable?
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If it is 10mm² T&E on a standard 32A 'cooker' circuit then the cable can be run anywhere.

The maximum derating for even completely surrounded by thermal insulation is 50%, so for 10mm² T&E this would result in 32A.

It can rest on the plasterboard.
Cheers, it would appear they have a 50A RCBO lined up to go on this (or at least thats whats in the board at the mo....)

I guess this will still be ok in the void given its not touching insulation? They aren't due to the end of the week so i guess ill find out then!

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