ring main and cavity wall insulation

[stardanny]

Hi.

Will the ring main cables in cavity be a problem as we having cavity wall insulation put in at my parnet's house?

There are two cables coming from CU through wall then drop about 2m down inside cavity to through hole below ground floor board to supply 5 downstair sockets.

The rest is fine.

Will it need to move it or will it be alright?

Dan.

 

[PrenticeBoyofDerry]

When you say cavity do you mean the void between the 2 leafs of the external walls?
or a stud wall?
What size are the cables and what are the fuse/breakers rated at for the circuit?
Does the insulation completely surround the cables?

 

[stardanny]

The void between 2 leafs of the external walls. Outside wall of the kitchen.

Cable is 2.5mm T + E. Rewired in 1972.

30 amp. standalone 30ma RCD.

I think it will be blown insulation. not sure. They going to drill holes and fill into cavity.

Thanks.

Dan.

 

[sparkwright]

Ask what the cavity insulation installer thinks.

I'm sure with his experience he will know exactly what should be done.

Yep. You guessed it...

 

[PrenticeBoyofDerry]

The void between 2 leafs of the external walls. Outside wall of the kitchen.

The cavity is not the best place for cables to be routed and should not be in there!

I think it will be blown insulation. not sure. They going to drill holes and fill into cavity.

Yes that is what they do, they will drill holes in a grid pattern on your outside wall and pump the insulation in.

Cable is 2.5mm T + E.
30 amp.

So the chances are the cable will be totally surrounded thermal insulation, the correction factor of the the cable will be 0.50 of the capacity, which will drop it to 13.5Amps, which will not be acceptable on a 30A ring final circuit.
If it possible to re-route them, I would.

 

[1john]

So what will happen if they hit the cable/s, what if other cables are there that you are not certain about or dont know about and they hit them?

 

[stardanny]

Why it was there, I don't know, I wasn't born when it was rewired.

I am certain there are only 2 cables ring main, stranded, inside the cavity. I've checked all cables run.

I've spoken to a sparky and he say it will be okay as it a short run inside cavity.

I know 100% where is the cables in cavity to avoid it.

Dan.