Replacing light switch back boxes Ask questions and find answers to many subjects relating to electrics and electrical work

[rossmcd]

Hi

I am replacing several light [dimmer] switches - not moving location of switches. My current back boxes are only 16mm deep, for which there is very limited product availability.

Several attractive replacement dimmer switches require minimum 25mm or even 35mm back boxes.

So I have two options - to simply replace the current switches with ones compatible with 16mm back box, or a two-stage effort to first replace the back boxes (say with 25mm) then install new light switches that require 25mm back box.

My question, on which guidance would be very welcome, is...how difficult is it to replace back boxes? And are there any other related tricks or advice.

Thanks

[sparx]

Hi, not too difficult but WILL muck up some decorations as getting old boxes out without damaging cables means cutting clearence space (usually below) boxes.
Remove any fixing screws in back of box, if wallpaper cut short 45deg. lines from each corner & peal back 'flaps ' of paper. Cut 45 deg . slope along bottom edge of plaster, then with small hammer & chisel tap back of box until free, pull carefully down & out with pliers. To replace use small masonary drill to make series of holes around edge of original box hole, then drill criss-cross holes all in back of hole ,chisel out whats left of masonary, fit new box with rubber grommet around cable hole, refix box, make good mess with filler, glue wallpaper back Voila! easy-peasy, regards SPARX
PS all above with fuseout!!!!!

[rossmcd]

thanks sparks
your suggestions are very practical. but likely very messy! in the end i've decided to simply installed replacement dimmer switches of narrow 16mm depth. shame as i'd have loved to install some snazzier light switches but there you go. thanks again for the timely and thoughtful response.