What depths do pattress-boxes (wall-boxes) come in?

[curium]

Hi

I've just changed over some socket fronts that my wife bought but I can't get the switched spur fronts on as it has a lower profile than the standard white ones and so more of it protrudes behind. All the 2-gang plug sockets I'm managed to get on but the extra cable behind the switched spur is the spanner in the works

It's a Hamilton Hartland fused switched spur with neon (if that makes any difference).

The back boxes are mounted on breeze block and then made flush with hardwall and multifinish plaster. Removing the box is bound to damage some of the surrounding plaster (newly painted!).

I'm just after any suggestions as my only thought now is to remove all the back boxes, chase out the breeze-blocks and install deeper back boxes. Is this my only option (other than put the old switches back on)?

What depths do back boxes come in? Will I need an SDS drill or should a normal drill with a hammer and bolster chisel do the job?

What do I do about the cables supplying the existing back boxes? I guess I can cut away at the metal to try and remove the box without damaging the supply cables.

I'm just after any suggestions/tips really as I'm pretty sure there's only one way to sort this to my wife's satisfaction

 

[plugwash]

If it's newly painted hopefully you still have some of the paint to touch up

Normal socket boxes are 25mm, the next standard depth being 35mm so you will need to take about 10mm out of the back of the hole, i'd think a normal hammer drill (you can soften up masonary a bit by drilling lots of holes) and bolster chisel would be fine.

 

[holmslaw]

..

 

[Space cat]

What depths do back boxes come in?

http://www.screwfix.com/c/electrical-lighting/metal-back-boxes/cat2470003

I doubt that you'll need anything deeper than 35mm.

Will I need an SDS drill or should a normal drill with a hammer and bolster chisel do the job?

Breeze block is soft stuff. Drill a hole at each corner and a few in the middle then chisel away the rest. If you've never tried this before, DO NOT hit the block square on with the chisel. Angle it so that it chips bits off. (I'm not a freemason but I'm quite cheap. )

What do I do about the cables supplying the existing back boxes? I guess I can cut away at the metal to try and remove the box without damaging the supply cables.

Cutting the metal away will be a mug's game - and you'll have the same problem in reverse when you try to fit the new box. You really have no option except to cut away the plaster on at least two sides. If all the cables come in the same side, cut the plaster out on the opposite side and one other until you can slide the box off the cables. If they're on opposite sides it's tough luck; you'll have to remove even more plaster.

 

[plugwash]

Box sizes - http://www.tlc-direct.co.uk/Main_Index/Boxes_and_Enclosures_Index/Boxes_Flush/index.html - you can also get extension collars to make the boxes deeper.

I doubt the wife will be happy with the nice new flat plate accessories sitting on surface mount collars and by the time you've removed the box to dig out the wall you may as well just fit a new box IMO.

 

[seasickstevie]

Rather than a bolster, use a narrow cold chisel
http://www.toolbox.co.uk/cold-chisels-5738-0000?gclid=CM63sYjwva4CFUEMfAodSUxlfQ

...and keep it sharp.

Or as holmslaw says, a comb chisel.
http://www.toolbox.co.uk/search?w=comb+chisel

Or even a combination of the two, and like plugwash says, stitch drill into the corners and edges first.

If you're careful and take your time, it's possible to do a neat job.

With the popularity of thin faceplates, I use deeper boxes as standard now (not that that helps Mr & Mrs Curium).

 

[Chit]

Is this an internal breeze block wall? Also how deep is it? A friend of mine a while back tried chasing an internal breeze block wall to install a new back box in it and went straight through it causing a whole in the wall.

Point being, be careful with it and take your time, breeze blocks can be very fragile!