Chasing Cavity Walls

cool hand luke

Lads sorry to jump on the post but what happens with chasing cavity walls? Say chasing the box out and it busts through how do you mount the box?

delly

Post moved to it's own thread and into the Electrical forum

Bruthal

cool hand luke wrote: »

Lads sorry to jump on the post but what happens with chasing cavity walls? Say chasing the box out and it busts through how do you mount the box?

,

M cebee

sand and cement

or bonding if it doesn't cause any corrosion

Bruthal

M cebee wrote: »

sand and cement

or bonding if it doesn't cause any corrosion

I must be going blind the way I read the OP:eek:

meercat

cool hand luke wrote: »

Lads sorry to jump on the post but what happens with chasing cavity walls? Say chasing the box out and it busts through how do you mount the box?

try and get a fixing through the sides if the box
if you are careful enough you can get the centre spine of the cavity block,screw the socket box in the middle here
i find metal boxs better here

then bonding or fillers

Bruthal

Yea the metal boxs are all id ever use. Plastic ones are useless imo. Double ones can be fitted to reach across the cavity and screw into the side corners to fix them, after drilling new goles through the box.

Or fix to the centre of the cavity as said, depending on where the box ends up, it its a single and so on.

M cebee

i normally set boxes with sand+cement,no screws
-but you have to come back to finish off next day

meercat

M cebee wrote: »

i normally set boxes with sand+cement

dont forget to cover the back of the lugs with insulation tape if you are using plastic boxs

cool hand luke

Lads fair play for all of the replies much appreciated. Just want to clear up one of the suggestions when you are bonding in the box. Do you fill the cavity fully with bonding then set the box into the bonding? Thanks again lads.

Bruthal

cool hand luke wrote: »

Lads fair play for all of the replies much appreciated. Just want to clear up one of the suggestions when you are bonding in the box. Do you fill the cavity fully with bonding then set the box into the bonding? Thanks again lads.

Well you could mostly fill it with the rubble you chased out of the wall, then bonding for the rest. I never fill the cavity myself, usually id cut the shape of the steel box out nice and tight for the box to fit, and fix it as described in other posts, with a bit of bonding around the box if a cavity does break through.

If you already have a big piece of the cavity opened, you can pack with rubble, or pieces of wood etc, then fill out with bonding to secure the socket.

The bonding can be neatly finished flush with the wall surface and front of box.

Take a photo of the opening which will give posters a better idea if you need any more suggestions.

cool hand luke

Touch wood hasn't happened to me yet but always wondered what was the solution. I am a sparks but have worked in industrial for the whole of my time and the little chasing I have done was in block walls.

Bruthal

cool hand luke wrote: »

Touch wood hasn't happened to me yet but always wondered what was the solution. I am a sparks but have worked in industrial for the whole of my time and the little chasing I have done was in block walls.

Yea it does happen alright. Sometimes the chase down to the socket or switch can hit cavities. And the box itself. It just depends on where the box ends up compared to the centre of the cavity anyway.

I prefer the industrial end myself.

cool hand luke

Robbie thanks for all the tips mate. So if you hit middle of the cavity could you bond both sides inside the cavity enough that you could set the box into it?

Also do you fill in your own chases?

The way I was told how to do it is. Brush out the chase and wet it so the wall doesn't suck all the moisture out of your filler to quick. Fill chase with filler. Let the filler dry and it will shrink back into chase. Finish with one more skim of filler and sand back when dry. The chase should be just deep enough to sink the oval conduit by a couple of mil.

A plasterer is probably going to have stroke reading this.

Bruthal

cool hand luke wrote: »

Robbie thanks for all the tips mate. So if you hit middle of the cavity could you bond both sides inside the cavity enough that you could set the box into it?

I Usually cut out the hole for the boxes nice and tight so very little bonding is needed. But sometimes a chunk of cavity breaks open, so Id just do what has to be done at the particular time to get a fixing and fill around the box.
If there is a big open hole, a ground made of wood could be made up and fixed so the box can be fitted flush with wall surface, and fill in with bonding then. Or you can fill the cavity with sand and cement and set the box into it.

Also do you fill in your own chases?

On rewires I do, with bonding to the wall surface level. The owner can then have it skimmed if painting the walls.

The way I was told how to do it is. Brush out the chase and wet it so the wall doesn't suck all the moisture out of your filler to quick. Fill chase with filler. Let the filler dry and it will shrink back into chase. Finish with one more skim of filler and sand back when dry. The chase should be just deep enough to sink the oval conduit by a couple of mil.

A plasterer is probably going to have stroke reading this.

I do wet the chase alright, but put bonding in. Bonding works well because it wont start flowing down the chase or bulging out of it, it stays put. Id prefer to have the conduit in 10 to 20mm at least. I sometimes make up ties from bare copper stripped from a bit of 1.5 pvc/pvc and loops twisted into the ends, and screw these to the wall in the chase around long drops to sockets etc, to secure the plastic conduit into the chase, which keeps it tight at the back of the chase while the bonding sets.

meercat

Great post Robbie

That's exactly what I do

cool hand luke

Robbie and Merrcat you are both my new domestic wiring and ETCI rules guru's from now on. Thanks a million lads.

By the way does anyone else use the rule of no more then 10 points (5 double sockets) on a circuit

Bruthal

cool hand luke wrote: »

Robbie and Merrcat you are both my new domestic wiring and ETCI rules guru's from now on. Thanks a million lads.

By the way does anyone else use the rule of no more then 10 points (5 double sockets) on a circuit

Yes most would keep to the 10 points per circuit, which is 10 sockets whether single or double. A double is still 1 point.

Just dont mention tripple sockets:D