Installation of an Additional Wall Dimmer and New Ceiling Light Fixture

Wires in a hole awaiting the installation of an electrical box
Adding a second switch

Dear Mr. Electrician: Is it possible to install an additional dimmer next to an existing one and connect a new ceiling light to the new dimmer?

Answer: Yes. However the methods used to achieve this type of installation will vary according to your building structure and the location of the switches and light fixtures. Below are photos of a simple dimmer and ceiling light installation in a condominium.

This was the existing dimmer switch for ceiling lights in the adjacent room.
This was the existing dimmer switch for ceiling lights in the adjacent room.
The existing dimmer switch box had the correct wiring (Hot and neutral) in it to facilitate the connection to another light fixture.
The existing dimmer switch box had the correct wiring (Hot and neutral) in it to facilitate the connection to another light fixture. A long thin screwdriver was inserted along side of the switch box to feel for any obstacles such as pipes or wood studs.
The existing one gang plastic electrical wall box has been removed and the hole has been made bigger for a new two gang plastic old work electrical box. The existing black switch leg wire was identified with green electrical tape. The other black wires get spliced together.
The existing one gang plastic electrical wall box has been removed and the hole has been made bigger for a new two gang plastic old work electrical box.  The existing black switch leg wire was identified with green electrical tape. The other black wires get spliced together.  The wood stud on the left side of this wall opening is perfect for attaching the new two gang plastic old work electrical box for additional support.
The access hole in the wall and the access hole in the ceiling were made using "The Grabowski Method" (Cut at 45 degree angle) to facilitate the installation of a new wire to feed the new light fixture.
The access hole in the wall and the access hole in the ceiling were made using “The Grabowski Method” (Hold the Saw at 45 degree angle) to facilitate the installation of a new wire to feed the new light fixture. A large hole is needed to fit the Milwaukee right angle drill into the wall to drill up into the top support plate.
This hole was made using "The Grabowski Method" of cutting holes in drywall. You simply hold your compass saw at a forty five degree angle when cutting to give you a beveled edge. This makes it much easier to patch the hole using the same piece of cut out drywall and some joint compound.
This hole was made using “The Grabowski Method” of cutting holes in drywall. You simply hold your compass saw at a forty five degree angle when cutting to give you a beveled edge. This makes it much easier to patch the hole using the same piece of cut out drywall and some joint compound. Lately I have been using my Milwaukee Cordless Multi-Tool to cut such holes.
This hole going up into the ceiling was made with a Milwaukee 0721-20 V28 28-Volt Lithium-Ion 1/2-Inch Cordless Right Angle Drill This view is the inside of the wall through the hole in the previous photo. The big hole in the wall was needed to accommodate the big angle drill and a long auger drill bit.
This hole going up into the ceiling was made with a Milwaukee 0721-20 V28 28-Volt Lithium-Ion 1/2-Inch Cordless Right Angle Drill.  This view is the inside of the wall through the hole in the previous photo.  The big hole in the wall was needed to accommodate the big angle drill and a long auger drill bit.
The hole for the octagonal electrical box that will support the light fixture. The existing cables in the ceiling are set back far enough to provide clearance for the new box. You can see the side of the laminated beam on the bottom edge of the hole.
The hole for the octagonal electrical box that will support the light fixture. The existing cables in the ceiling are set back far enough to provide clearance for the new box. You can see the side of the laminated beam on the bottom edge of the hole.
A view inside of the ceiling. This is the other side of the laminated beam from where the octagonal box is located.
A view inside of the ceiling. This is the other side of the laminated beam from where the octagonal box is located. You can see that there is an existing wire hole from the original installer already drilled.
The fishtapes have been pushed in and are ready for the wire to be attached and pulled in.
The fishtapes have been pushed in and are ready for the wire to be attached and pulled in.
The fish tapes have been pushed in and are ready for the wire to be attached and pulled in.
Two short pieces of fish tape will be used to pull the wire.
The wire is pulled in and ready to have the deep octagon electrical box installed in the ceiling.
The wire is pulled in and ready to have the deep octagon electrical box installed in the ceiling.
This is the view inside of the ceiling with the new wire pulled in through the hole in the laminated beam.
This is the view inside of the ceiling with the new wire pulled in through the hole in the laminated beam.
A 4-Inch diameter by 2-1/8-Inch depth octagonal box was used here to give better leverage support as the box was mounted on the side using #10 x 1-1/2" sheet metal screws and one fender washer where the knock out was. The fender washer allows for a little adjustment to get the box positioned correctly. The other screws lock it in place. Note the copper ground wire attached with a 10/32 screw.
A 4-Inch diameter by 2-1/8-Inch deep metal octagonal box was used here to give better leverage support as the box was mounted on the side using #10 x 1-1/2″ sheet metal screws and one fender washer where the knock out was.  The fender washer allows for a little adjustment to get the box positioned correctly. The other screws lock it in place.  Note the copper ground wire attached with a 10/32 screw.
The light fixture hook and bracket are attached to the deep octagon electrical box in the ceiling.
The light fixture hook and bracket are attached to the deep octagon electrical box in the ceiling.
The light fixture hook is attached to the deep octagon electrical box and the access hole in the ceiling is patched.
The light fixture hook is attached to the deep octagon electrical box and the access hole in the ceiling is patched.
Once the wires are tucked up inside the deep octagon electrical box, the canopy can be pushed up and held in place with the locknut.
Once the wires are tucked up inside the deep octagon electrical box, the canopy can be pushed up and held in place with the locknut.
I usually leave extra slack on the wires for chandeliers in case the homeowner decides to lower it or use it on a high ceiling in the future. Having the deep octagon electrical box in the ceiling lets me tuck some extra chandelier wire slack up there. White electrical tape was put on the chandelier neutral conductor to make it easily identifiable.
I usually leave extra slack on the wires for chandeliers in case the homeowner decides to lower it or use it on a high ceiling in the future. Having the deep octagon electrical box in the ceiling lets me tuck some extra chandelier wire slack up there.  White electrical tape was put on the chandelier neutral conductor to make it easily identifiable. Normally shallow ridges on the one side of the fixture wire indicate the neutral.
The wires are tucked up inside of the deep octagon electrical box. This is another good reason to use a deep box, there's more room for the excess wires.
The wires are tucked up inside of the deep octagon electrical box. This is another good reason to use a deep box, there’s more room for the excess wires.
The new two gang plastic old work electrical box is ready to be mounted in the wall
The new two gang plastic old work electrical box is ready to be mounted in the wall
 Close shot of the inside of the two gang plastic old work electrical box for the two dimmers
Close shot of the inside of the two gang plastic old work electrical box for the two dimmers
The two gang plastic old work electrical box is mounted to the wall by tightening the screw in the upper right corner and the screw in the lower left corner. The wings will be pulled from behind against the wall and create a tight wedge. In addition a #8 x 1" sheet metal screw was driven through the box into the adjacent wall stud for additional bracing.
The two gang plastic old work electrical box is mounted to the wall by tightening the screw in the upper right corner and the screw in the lower left corner. The wings will be pulled from behind against the wall and create a tight wedge. In addition a #8 x 1″ sheet metal screw was driven through the box into the adjacent wall stud for additional bracing.
The Lutron Diva Dimmers are wired in and are ready to be mounted on to the two gang plastic old work electrical box.
The Lutron Diva Dimmers are wired in and are ready to be mounted on to the two gang plastic old work electrical box.
Close shot before the dimmers are mounted to the wall. All of the white neutral wires are spliced together and tucked into the back of the box first
Close shot before the dimmers are mounted to the wall.  All of the white neutral wires are spliced together and tucked into the back of the box first
The completed installation of the Lutron Diva Dimmers
The completed installation of the Lutron Diva Dimmers
A small piece of wood was screwed in place so that the drywall would have something to attach to. This piece of drywall was cut out using "The Grabowski Method" where the blade is held at a 45 degree angle
A small piece of wood was screwed in place so that the drywall would have something to attach to. This piece of drywall was cut out using “The Grabowski Method” where the blade is held at a 45 degree angle
The patched ceiling hole. When "The Grabowski Method" is used to cut holes, they can be patched easily using only joint compound and No Tape.
The patched ceiling hole. When “The Grabowski Method” is used to cut holes, they can be patched easily using only joint compound and No Tape.
The patched hole in the wall. This requires another coat of joint compound, some sanding and then paint to give it the finished look
The patched hole in the wall. This requires another coat of joint compound, some sanding and then paint to give it the finished look
The completed wiring job for an additional dimmer and a new light fixture. All that remains is to have the holes finished and painted.
The completed wiring job for an additional dimmer and a new light fixture.  All that remains to be done is to have the holes finished and painted.