electrical backboxes

[Dopeydaz]

Good afternoon all, in the process of building an extension, building control want a triple layer of plasterboard on the external wall as it goes on to the boundary with a neighbour.

They also want the socket boxes to be fitted with intumescent gaskets to maintain the fire resistance of the plasterboard.

So my question is, which socket boxes should i use?

Most dry lining boxes as far as i can see are only for single layers of plasterboard?

my thinking was i could just cut a bigger hole in the first 2 sheets of plasterboard then the drylining box? or would it be better to use metal boxes screwed on to a timber baton?

Thanks
Darren

 

[PrenticeBoyofDerry]

http://www.safelincs.co.uk/astrofla...rt/?fGB=true&gclid=CPPn-uXYgs8CFbQW0wodS2oF1A

If you use dry-line boxes, you will need to make provisions for the fixing lugs on the box. They will only catch a single skin of plaster board. So on the right and left edges of the two layers below, they will need to be notched out for the lugs.

Then there always these to consider!
https://www.tlc-direct.co.uk/Images/Products/size_3/WA4235.JPG

https://www.tlc-direct.co.uk/Produc...=finalurl_v2&gclid=CJuBjJfags8CFTYW0wodUM0AbQ

https://www.tlc-direct.co.uk/Technical/DataSheets/Fire_Hoods/TLC_Fire_Boxes.pdf

 

[Iggifer]

Seems a bit over the top to me.

How are you building the wall? You could use these and you might only need to enlarge the hole in the rear board, as it looks like the lugs move back far enough to accommodate two layers of board.

Worst case scenario is you cut them out to the proper size, and then just nibble away the plasterboard where the lugs will need to be afterwards. Not as tidy but leaves more plasterboard in place

 

[Lectrician]

Metal boxes all the way.

 

[securespark]

Seems a bit over the top to me.

Yeah, but if BC are involved you gotta go with their decision or know the BR's well enough to have a discussion about why you shouldn't do as they suggest!

 

[Lectrician]

Is there no solid masonry wall between you and neighbour?

You usually then have two stud walls with a gap between them, plasterboard on the back of one wall, two layers on the front of that wall, and three on the front of the other (as none on the back).

 

[Dopeydaz]

Thanks everyone.

Yeah I think a triple sheet of plasterboard is overkill. Not my decision though. The wall is timber frame with block outerleaf that will be roughcast.

So there is nothing the other side of the wall. Downstairs is a kitchen and a wet room so the only room it will affect is the kitchen. Upstairs is a bedroom and a bathroom. So I will just put the sockets on a different wall in the bedroom.

 

[sparkwright]

I would go with deep metal boxes.

Put the bedroom sockets where you want them, no point in making do.

 

[Lectrician]

For the kitchen, I would be tempted to cover the wall in plywood, and then the three layers of plasterboard. You then have great fixings for cabinets and anything else. The metal back boxes could then be screwed directly to the ply, using 35mm boxes would leave them a couple mm shy of the wall finish. The intumescent gaskets are cheap enough. Just stuff them in.

 

[securespark]

Just stuff them in.

Nice to know you are a conscientious worker!