Hi,
I am considering having my cavity walls insulated, but have recently discovered that all the electric cables from the consumer unit run within the cavity wall, and i was wondering if the extra thermal insulation will have an effect on the cables?

In more detail, I have a brick outhouse/shed attached to the house. The consumer unit is located within the shed. The cables coming out of the consumer unit travel within the cavity up to the first floor where they appear under the floor boards.

The house was built in the 1950's and the wires are PVC with the sockets connected using a radial system.

So i guess i am really asking is it still acceptable to have cables run inside a cavity wall?
Am i looking a re-wire here?
many thanks
Alan

it's one of those old scenarios: -

they used to wire like that all the time. there are millions of houses still wired like that now.

yes the insulation will make a difference to the cables but maybe not enough to do as much damage as the age of the insulation could do. if you have cables run like that then i would suggest getting it checked out (tested) by a sparks to see what condition it is in. they recommend a max of 25 years but i suspect yours is more likely to be 35+. that alone means your earthing may not be up to scratch, fuse box etc etc etc.

the thermal increase will only heat the cable sup a lot more on high loading. if you don't use anything massive the chances are you will get away with it although it is not an ideal situation.

Thanks for that.
It's turned out to be of of those jobs that keeps getting more expensive!
Alan

The british standard for cavity wall insulation does not permit insulation to be installed into cavities containing cables. The installer should refuse to fill them.

Thanks for that.
I am considering getting someone to bring the cables directly through the wall into the house (i guess using ducting). Will I be able to have the walls insulated if the cables are just passing though the cavity?
many thanks
alan

that's one of them catch 22" rules though James. i bet you too have seen loads of them done in this scenario. at the end of the day, they won't know if cables are int he cavity or not unless they have a sparks take everything apart before they do every job and, although i don't know, i would bet they don't.

When we lived in Blackpool, we got the cavity wall insulation done for free under the Warmfront Scheme for Disabled people.
Guy came and accessed the loft insulation at the same time but nobody checked the electric wiring as to where it was routed.
It didn't go in the cavity as I had just done a full rewire myself but no one checked before pumping in the insulation.

dave

_________________
You can always tell a Yorkshireman,
But you cannot tell him much.

Your right, If you read the packaging of loft insulation, it normally says that all cables should be lifted above the insulation....I can't honestly say i'v ever seen it done!