running cables in new loft

[antsbradley]

Hi,

Installing first fix in new extention, and contemplating best way to run lighting cabling in loft space. The cables need to run both along the timbers and across them, the timbers are only 75mm high so will have 225mm of mineral insulation sitting on top of them (i.e. 300mm total, and its not being boarded / used for storage etc).

Running along the timbers should they be on the side near the top? running across the timbers should they go down the side, across the ceiling and back over the next one, or should that come up the roof truss and along batons clear of the insulation?

Just worried about 1) heat build up (although its only lighting circuit in loft), and 2) them getting trodden on ontop of the timbers as hidden by insulation if anyone ever needs to go up there for maintainance of roof etc.

Many thanks!

Anthony

 

[Chri5]

Keep the cables away from the insulation, it derates the cable capacity by 50% +

Although not perfect, it would be better to fix some horizontal baton to the roof trusses and clip the cable along the baton.

If you have any spot lights the insulation needs to be clear of the fittings to prevent over heating