Cabling and roof insulation

[Kes]

Hi,

In an attempt to reduce the heating bills I am thinking of increasing the nominal couple of inches of insulation in the roof space (the orange fibery stuff) to something closer to the now recommended 10 inches. The existing cabling in the roof, both 2.5 and 1 sq mm, was installed along with the insulation about twenty years ago. The cables lie mostly underneath the existing insulation.

As I will have to crawl all over the roof space what's the best way to position the cables? Would it be better if I laid them on top of the new insulation, if there is sufficient leeway? What do I do if the cables are tight and can't be lifted above the insulation. Will this matter? And will the weight of the cables press into the insulation?

Rgds.

 

[Qedelec]

Cables enclosed in insulation have a lower current carrying capacity and thus the specification for the circuit when designed will have been affected. Worst case senario, cables can over heat and cause a fire. If possible lay the cables on top of the insulation. If in doubt get an electrician to check it out.

 

[Steve]

It might be wise to clip the cables to the roof rafters overhead - this will keep them away from the insulation. Though you will have to replace a lot of lengths of cable for this. Cable is cheap. Fire repair isn't insulation on just one side will reduce the capacity of the cable.