Installing plasterboard back box on external wall

hessodreamy

On the front external wall under the window:

I had a mains box mounted onto the plasterboard. After I had the plasterboard replaced I thought it would be a good idea to use a back box that mounts into the plasterboard, like this:

Now I'm wondering if this is a bad idea to install it on an external wall? I'm not sure how much room there is between the plasterboard and the tiles. I might have to cut out or compress some insulation to get it in. Also concerned about water ingress.

Would it be a much better idea to use a standard surface mount box?

tacpot12

What do you want to be able to plug in? Do you need a double socket or would a single socket do?

Neither of that style of box are designed to be used outdoors, and you won't comply with the regulations if you install either of them.

stuart45

I think he means inside but on the external wall.

hessodreamy

https://forums.moneysavingexpert.com/discussion/comment/82148863#Comment_82148863

That's right - inside but on the external wall.

Eldi_Dos

You can get camera probes (endoscope) which work with your smart phone quite cheaply now, using one of these you would only need to drill one small hole in the area you intend to put the box.Once you have seen what is behind plaster board you can then plan what to do.

My own inclination would be to put any new socket on main wall either side of window.

cpc Farnell have a Borescope Inspection Camera with its own screen that looks a nifty tool and comes in around £ 30.

stuart45

The normal construction of those tiles bays is from the outside - tiles, timber battens, breather membrane or felt, ply or OSB sheathing, 4x2 timber studs, insulation in between the studs, vapour check, plasterboard.

Where electrics are going they would put a 25mm service void. I'd doubt you have one there.