Keeping cable away from insulation in joist void

[marshr02]

Any thoughts on this; 200mm joists with 100mm of mineral wool quilt to be installed in lower half. Have cables going across joists through centrally drilled holes. Left as is the mineral wool will be squeezed/touching against this cable, meaning the cable CCC is too low. I was going to fix some 9mm ply under the cables to hold off the insulation. My question is; either I fit some ply with an air gap of say 20mm to the cable, or my preference is the ply fits tight to the underneath of the cable, with the insulation below - would this second option still be ref B (cables in void). Thanks for any help.

 

[marshr02]

I know what you mean. I found a picture of what I did in case it helps at all.

View attachment 18957

Thanks Tuttle - that's exactly where I'm at. Looks okay.

 

[marshr02]

Thanks Richard. Yes - mid level floor - acoustic & fire protection. Don't seem to be able to get 25A RCBOs for this contactum CU. Looking at Tuttle's picture, this is good enough for B in my opinion (which I would be happy to put 4mm on a 32A breaker as CCC quoted at 30A is near enough given other positive variables) My problem is I'm installing from below, and so later when the insulation is installed who knows how far up it could be pushed. Summary - I would be happy with Tuttle's installation, but am going to put ply under cables to prevent the insulation being squashed higher into cabling....hope that makes sense....thanks for all the great replies/help