LAP switch back box depth

overskilled · Dec 14, 2012

Anyone have any idea what the required backbox depth for a 2G 2Way LAP white light switch is?
LAP 1-Gang 2-Way 10AX Light Switch White | Screwfix.com
Screwfix website doesn't say, should be ok with the existing 16mm the client has, but just want to check before buying the switch, if needed then I'll stick a 25mm back box in, but the client ideally doesnt want the back box replaced for cost reasons. (other work going on so trying to keep the budget under control.

brman · Dec 14, 2012

Don't have a 16mm backbox lying around to try but the switch is 9.5mm deep with rear entry for the cable. I reckon that should just fit as long as you don't have lots of cable behind it.

loop3 · Dec 14, 2012

Buy it and try it.

loop3 · Dec 14, 2012

If it doesn't fit , dremel the back of the box out and chisel the wall. Job done.

overskilled · Dec 14, 2012

Thanks
Should be ok, just 1 3+E and a T+E in 1mm2 so nothing massive.
Light switch is a prior addition to the house, and whoever installed it, stuck it right on top of a 4" tall 4" deep noggin/dwang - the wall is only ~10 inches wide from door frame to the adjacent wall...so why they decided to use such a thick piece I have no idea....no load bearing, it just allows the door frame to stand there.
Mentioned the above as the customer needed another feed running into the loft space for some new soffit mounted external LED lights..only route upwards without serious channel cutting is this wall (rest are engineered hard brick...really hard brick)...had to cut a sizeable piece of plasterboard out to get the drill in to drill a different cable slot in the timber as the current slot/hole barely allows a pair of 1mm2 T+E's through...then discovered the noggin was a lot thicker than I expected.. Always some gremlins lurking to mess up my day / schedule lately it seems....
For the record I'm not a fan of 16mm back boxes, 25mm just makes life a lot easier and gives options for the future.