Things You'll Need
14 solid black THHN wire
14 solid green THHN wire
Yellow wire nuts
Orange wire nuts
Each color of wire designates its purpose. Black and red wires are hot wires, meaning these wires are the wires that deliver the electricity to a location. White wires are neutral wires, which complete the circuit of electricity to allow the electricity to power a location. Bare copper or green wires are the ground wires, which are the protection. In the event of a short circuit, the ground wire diverts the power to the ground though a grounding bar attached to the main breaker panel. Although there are other wire colors, these colors are the most common in residential services.
Each color of wire nut signifies the number of wires that can be connected together safely. Your wire nut package will list the specifications for each color of wire nut.
Make sure that the electricity is off to the area in which you are working.
A white, or neutral, wire is never connected to a switch. Doing so would cause a short in the circuit and immediately trip, or turn off, the breaker at the main panel. In the event that the breaker fails to trip, it could cause an electrical fire.
You must not exceed the number of wires in each wire nut as specified in this article. The colors of wire nuts and the number of wires that can be twisted together have been specified in order to safely wire in your home. Any deviation from the color of wire nuts and numbers of wires could cause a short circuit and a possible electrical fire.
Your gang box looks like an octopus with wires emerging from it like the tentacles of the Kraken that sank the Black Pearl. How to wire three switches in a gang box seems a bit daunting just looking at it. You have only one power supply wire and three different fixtures to be wired to that power supply. Tame the tentacles and provide the power that will allow each fixture to be operated by a dedicated switch.
Turn off the power to the circuit at the breaker panel.
Make pigtails. You will need three black wire pigtails and five green wire pigtails. Cut three six-inch lengths of 14 solid THHN black wire. Use a wire stripper/cutter to strip ½ inch of insulation off of each end of the black pigtails.
Cut five six-inch lengths of 14 solid THHN green wire. Use the wire stripper/cutter to strip ½ inch of insulation off of each end of the green pigtails.
Wiring the Neutral Wires
Connect the white, or neutral, wires together in the gang box. Currently you have a total of four white wires. You have the power supply white wire that leads back to the breaker panel and you have the three white wires that connect to the three fixtures. Use a yellow wire nut and twist all four wires together.
Tape the wire nut to the wires with electrical tape. Wrap the tape around the wire nut and onto the wires. This is not necessary but will give added security.
Push the four white wires into the back of the gang box.
Wiring the Hot Wires
Connect a black, or hot, wire from each of the three fixtures to the top screw on the right side of each switch. Tighten each screw.
Connect the black wire from the power supply to all three of the black pigtails. Twist all four black wires together with a yellow wire nut. The power supply wire is the wire that connects directly to the breaker panel. Tape the wire nut to the wires with electrical tape. Wrap the tape around the wire nut and onto the wires.
Connect each black pigtail to the bottom screw on each of the three switches. Tighten each screw.
Wiring the Ground Wires
Connect two of the green pigtails to the bare copper ground wire. Twist the wires together with an orange wire nut. Tape the wire nut to the wires with electrical tape. Wrap the tape around the wire nut and onto the wires.
Connect one of the green pigtails from the orange wire nut to each of the bare copper ground wires that are connected to the three fixtures. Twist the wires together with a yellow wire nut. Push the wires into the back of the gang box. Tape the wire nut to the wires with electrical tape. Wrap the tape around the wire nut and onto the wires.
Connect the remaining green pigtail in the orange wire nut to the three remaining green pigtails. Twist these four wires together with a yellow wire nut. Tape the wire nut to the wires with electrical tape. Wrap the tape around the wire nut and onto the wires.
Connect each of the three green pigtails to the green ground screws on each of the three switches. The green ground screws are located at the bottom left of each switch. Tighten the green screws.
Installing the Switches
Connect all three switches to the gang box. Each switch will connect to the gang box by screws, one at the top of each switch and one at the bottom.
Cover the three switches with a triple switch cover plate. The cover plate will connect with screws, three at the top and three at the bottom.
Turn the power on to the circuit at the breaker panel.