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Mounting Accessories in Solid Walls

Undeniably the best way to mount wiring accessories is to fit them over recessed mounting boxes, so that only the accessory face plate projects from the wall surface. The cable run to recessed boxes should also be recessed into the wall surface. This not only looks neat; it also helps to protect the face plate from accidental damage. However, it also means more work for you, since you have to chop out some of the mansory behind the plaster - fairly easy if your walls are built in soft insulating blockwork, but hard work if they are built with dense bricks.

It is important to remember that the mansonry in internal walls and the inner leaf of external walls is generally only 102mm thick, so if you are too heavy-handed with your hammer drill you may chop a hole straight through it, and have some awkward repair work to carry out as a consequence. The technique shown here is designed to minimize any risk of that occuring.

What to do?

As before, start by marking the position of the new accessory on the wall surface, and also the line of the cable run to it. Then use a masonry bit in your electrical drill to honeycomb the mansonry with a series of closely-spaced holes, drilled to a depth just greater than that of the box.

Marking box position Chopping out the waste

Next, use a sharp cold chisel or hummer drill to chop out the honeycombed waste to the required depth. Chop out the cable chase too, and test the box for fit in the recess. Chisel away the base a bit more if necessary to get a good fit.

Push out one of the circular knock-out plates in the side or back of the box to allow the cable to enter, and fit a grommet (rubber washer) in the hole to stop the cable chafing on the metal.

Mark the positions of the box fixing holes, drill and plug the holes and screw the box in place. Run in the cable and finish off by filling around the box.

Fitting grommet Securing back-box and feeding the cable

Point ot check: