Unlike a three-way switch circuit where a pair of switches at different points in the room control a single fixture, double-gang switches use a common power source to control a pair of lights independently. Wiring a double-gang configuration is no more difficult than a single-pole switch/fixture circuit, except for the extra cable run that must be fished across the ceiling. Key to this project is keeping track of which wires belong with which fixture/switch combination.
Locate a power receptacle to supply electricity to the circuit.
Make cuts for the fixtures and double-gang switch box. Cut an access hole at the top of the wall above the switch hole.
Prepare the power-to-source run. Draw a line at the top of the skirting boards between the power source and the switches. Remove the skirting boards with the hammer and putty knife. Number them for easier replacement. Draw a parallel line 1.3 cm (1/2 inch) below the previous line and cut along this line. Remove the plasterboard and drill holes through the exposed wall studs for the cable.
Install the switch and fixture hardware. Remove knockout panels in the switch and junction boxes for the wires. Attach the junction boxes to the brace bars and hang the bars between joists through the ceiling fixture holes. Make sure the junction boxes are flush with the ceiling.
Run the cable to each fixture from the switch by feeding fish tape through the access hole and across the ceiling to each junction box. Connect the electric cable to the fish tape and pull it back toward you. Drop the cable down and into the switch box. Wrap a piece of tape around each end of the black wire from Fixture 1 to the switches to distinguish it.
Turn off the power to the circuit and remove the power source receptacle from its box. Run cable from the receptacle box through the stud holes to the switch box.
Connect the power-source cables using "pigtails" (see Tips). The black pigtail connects to the brass terminal while the white pigtail connects to the silver terminal. Ground the green wire pigtail to the receptacle box.
Connect the wiring at the switches. Attach the taped black wire to one of the terminals on Switch 1. Attach a short black wire to the other terminal on Switch 1. Connect this black wire to a short black wire attached to a terminal on Switch 2 and the black wire from the power source. Connect the remaining black wire from Fixture 2 to the remaining terminal on Switch 2. Connect all white wires together. Connect the ground wires together and ground to the switch box.
Connect the wires at the fixture, black to black, white to white and green to green. Hang the fixtures according to the manufacturer's instructions.
Replace the skirting boards, repair the plasterboard hole and restore power to the circuit.
Make pigtails by connecting a short wire to each terminal and connecting the run wires to this short wire. Electrical codes prohibit connecting more than one wire to a terminal.
Tips and warnings
- Make pigtails by connecting a short wire to each terminal and connecting the run wires to this short wire. Electrical codes prohibit connecting more than one wire to a terminal.