Cavity drill bit question

lagi

I am going to fit an external socket and will need to drill through house and cavity to reach outside (2.5mm cable). What size drill bit, diameter and length would i be requiring for this. Also would like to put up some external lighting so cable would be 1.5mm and will be drilling slightly upwards to stop water ingress?

(I will be running cable, fitting, but not connecting to save money.)

Also is it exceptable to run cables through and up the cavity void, thus saving chasing out?

thebaldwindowfitter

10mm ariel bit about 350mm long and dont know wether its aginst regulations to drop cables down cavity im sure it is

lagi

Thanks, just drilled a bit of wood with a 10mm hole and found it hard to push the 1.5mm through, seen a 12mm so going to go for that . Had to go for 400 length.

Didn't realise there are some real long ones, couldn't imagine using them. I guess you start off with smaller length then change to the longer ones.

ariba10

If it is a one off job, it might be cheaper to drill a small pilot hole through with a thin drill bit and then enlarge from both sides.

27col

My main drill for cavity walls is a 16mm SDS. It is at least 400mm, if not longer. It will make a hole big enough for 2.5mm cable. If you are drilling from the inside, it is likely, that as the drill breaks through to the outside, there will be some "spalling" of the face of the brick. If you intend to put a socket over this, then it does not matter too much. otherwise it can be a bit unsightly. If you can drill from the outside inwards, then the problem will not occur. Or if it does, it will be on the inside and can be easily filled and repainted. If you are going from the outside then drill through the mortar joint to make it easy on yourself.

amarg

Use a 16mm drill bit.

When you get 80% of the way through the final drilling distance switch off the hammer action, then you do not knock a large piece of brick off the wall.

Then cut a piece of 15mm speedfit plastic pipe to the correct length and line the hole with it, this protects the cable in the cavity.

Push the cable through and seal the pipe and cable with silicone

27col

You are right amarg. I had forgotten about switching off the hammer action. The damage to my bricks was done by the chap who ran in the cable TV. Presumably he forgot to turn off the hammer action.

TimBuckTeeth

I would check with the electrician what type of cables to use, maybe standard twin and earth is not suitable.
Security lights often have a grommet or cable gland suitable for a circular cable.
If the cable to the socket does not go directly into the back of the waterproof socket box and runs for any distance on the external wall then it will need to be mechanically protected either by conduit or by using armoured SWA cable.

lagi

I am now going for a 12mm (because i had already ordered it) and a 16mm one too. Had similar problem on garage where it blew the render off by me pushing too hard drilling outwards. I didn't know then, so hopefully will be more careful next time. Good point about using the mortar joint, also like the pipe idea.

There will be no cable run on outside of house as this will spoil the look, so i have decided to make up a temporary lead with plug on to fit to the new lamps so i can move them around the wall so i get the right lighting height / ambience etc. It will be a bit like an indoor lamp but they will be taken at night to test. Once i am happy with positions i will mark it, drill and run cable then electrician can come and connect me up. This way i will know how its going to look without drilling in the wrong place.