Running cables in voids

[Barnman]

I am renovating a barn which has vaulted ceilings. The purlins are exposed but the rafters will be covered in plasterboard. After the insulation has been placed between the rafters there is a small space on the rafter between the lower edge of the rafter and the insulation of about 1.5cm where lighting cable can be run - is this permisible. It will not be enclosed in any conduit or trunking. It would be very close under the plasterboard but this will be screwed to the joists.

 

[fattony]

Cables should be adequately supported, is there some way you can clip the cables?

 

[Barnman]

Yes cables would be clipped to side of joist.

 

[fattony]

I think the regs state the cable should be clipped 50mm from the top or bottom of the joist, ideally in the middle but twin and earth cable can be clipped to a joist without having any containment such as trunking or conduit.

 

[securespark]

If you (for example) run a cable down a channel between two joists on a upper storey, the only thing supporting that cable is the plasterboard or lath & plaster ceiling. Isn't that sufficient?

 

[Barnman]

There isn't 50mm available. I can't be the only one with this problem. Maybe it is better to run the cables above the insulation between that and the roof felt but that would reduce the required gap and may cause moisture. If I used conduit - metal/plastic would that be OK.

 

[fattony]

you can only work with what you have, the idea of the 50mm is to try to stop the cable being damaged when the ceiling is to be installed, if a screw misses the joist and goes up the side of it a cable close to the plasterboard is likely to become damaged

 

[Barnman]

So - because that is all there is it would be permitted - even though it is not ideal.

Thanks for the advice and help - it is appreciated.