Loft insulation - wiring under or over it

HappyG1rl

Should the electrical wiring in the loft go under or over the loft insulation?

economiser

Years ago I was always told that the wiring should not go under the insulation but with the amount of insulation required these days it is often impractical to do the wiring after the insulation is put in.

Jonesya

Take care when removing the vermiculite as some vermiculite products are/were contaminated with asbestos.

benood

Our electrician was banging on about our insulation the other day from what he was saying you're supposed to wire under it nowadays.

baldelectrician

benood wrote: »

Our electrician was banging on about our insulation the other day from what he was saying you're supposed to wire under it nowadays.

I would be concerned.

Cables have to be de-rated by 50% if totally enclosed in insulation.
Most of the time people don't pay attention, but it is particuarly important for shower and other cables that carry high currents.

ps keep insulation clear from spot lights.


it is advisable to keep cables out the road of insulation, but this cannot always be achieved.

Nobleck

Ideally the cables should be on top, as Baldy said the cable ratings would be affected slightly if the cable was under the insulation.

Poppycat

I was lead to believe its best to lay the cable over where possible. Just like it is when using a extension lead with high powered tools/appliances to let the cable all out so as to reduce over heating.