Installing a Surface or Flush Mounted Electrical
Box
Installing Electrical Boxes
Introduction:
There are
basically two types of electrical boxes available;
metal electrical boxes and plastic electrical
boxes. Each of these boxes can be mounted in a
different way. Installing a surface or flush
mounted electrical box is an easy DIY project. A
flush mounted box is attached directly to the wall
surfaces. They are generally used in garages or
basements.
The flush mounted box is the most common method for
installing electrical boxes but they can also be
mounted to the wall surface. Most of these boxes
are sized for a single, double or more switches,
electrical plugs, or a combination of switches and
plugs.
Surface mounted boxes:
Surface mount electrical boxes are used to mount a
surface switch or plug. They are usually used in
garages or basements. The box is mounted flat on
the wall surface although some are mounted into a
small cavity within the wall.
Mounting on masonry walls:
-
For mounting on a masonry surface hold the box on
the wall at the position where you would want it
and ensure that it is horizontal using a spirit
level. When it is horizontally level, mark the
attachment holes and remove the box. Drill where
you marked the fixing holes to attach the box.
-
Determine where the electrical wiring will enter
the box and use pliers to break out the entryway
for the wire. Pass the wire through the hole and
align the mounting box up to the mounting holes you
have drilled. Use countersunk screws to fix the
mounting box to the wall. Before fully tightening
the screws use the spirit level to level the
mounting box.
Mounting on sheetrock walls:
-
Attaching a surface mount electrical box on
sheetrock or plaster walls can be done in a similar
way to masonry.
-
Place the mounting box on the wall and align it so
that the fixing screws go into the wooden frame or
2x4 behind the wall. Check that it is possible to
feed in the electrical wire from behind the box.
-
Mount the box and feed the electrical wiring into
the box.
Flush mounted on masonry walls:
-
On masonry walls place the metal mounting box
against the wall at the desired location and draw
around it with a pencil. Mark a path for attaching
the electrical wire.
-
Remove the material from within the marked area by
first scoring the pencil line using a masonry
chisel and hammer to cut the hole.
-
Once the material is removed insure the box fits
into the wall and then mark and drill holes to
attach the mounting box to the brick behind. Pull
through the length of electrical wiring required
and attach the mounting box in the hole.
-
Finish by plastering around the box and the cable
channel as necessary.
Flush mounted on sheetrock walls:
-
Once you have decided where the box is going to be
located, draw around the mounting box on the wall
ensuring that it is level using a spirit level. Cut
the hole in the wall using a sharp knife. Feed the
cable through the best wire entry hole in the box.
-
Fit a grommet to the wire entry hole and fit two
lugs to the mounting box. Then pass the cable
through the grommet and slide the box into the wall
so that both of the lugs are behind the wall. The
box should now sit behind the wall and flush to the
surface. Attach the electrical outlet or switch you
want for the location.
That is all there is to mounting a surface or flush
mounted electrical boxes.
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