(561) 625-5700
Gardens Home Management Services
Home Care Tips
Electric Dimmer
Gardens Home Management has the information and expertise to help you manage your home and keep you informed.
Home Care Tips and FAQ for Managing Your Home
» Back to Tips

How To Install an Electric Dimmer

How To Install an Electric Dimmer

Materials: Electric Dimmer Switch, Electrical Tape, Wire Nuts

Tools: Neon Circuit Tester, Slotted Screwdriver, Phillips Screwdriver, Wire Stripping, Pliers


Step 1) Turn Off the Power Never perform any electrical work without turning off the power. You can shut off the power to the switch by turning off the circuit breaker or by removing the appropriate fuse. Don’t take it for granted that the power has been turned off successfully. If the existing switch works, flip it to ensure that power is no longer running to it. Remove the screws that secure the switch and gently pull it away from the wall. Use the circuit tester to test the terminals and confirm that power is no longer running to the switch.

Step 2) Remove the Old Switch Note the color and location of each wire going to the old switch. You will be wiring the new dimmer in the same manner. One wire went to the terminal marked “common” or “line”. This is the hot lead from the breaker box. The other wire is the “load” going to the light fixture. If you see a bundle of wires in the back of the wall box, you can just ignore them. Using the screw driver, unscrew the wires from the switch and set it aside. Now we are ready to install the new dimmer switch. Just a quick note on wire colors. Any green or bare wire is always a ground. You may or may not have a ground wire in your wall box. If you don’t have one, the wall box should be steel and should itself be the ground. White wires are always neutral in homes with conduit, but can be hot wires in homes with cable wiring if they are marked with black electrical tape. Hot and load wires can be any color except green or bare, with white only used as noted above for cable systems.

Step 3) Attach the Ground Wire. If the switch box has a ground wire, take the ground wire from the dimmer and remove about 5/8-inch of pre-cut insulation. Put the ground wires from the switch box and electric dimmer side by side and secure them in place with a wire nut. Turn the nut clockwise to lock the wires in place, and then turn the wires until each one has a slight twist. For added security, use electrical tape to hold them together as well. If your wall box has no ground wire, attach the dimmer’s ground directly to the wall box with a ground screw.

Step 4) Connect the Hot and Load Wires. While the old switch used screw terminals to connect to the house wiring, dimmers typically have short wire leads instead. You will be using wire nuts to splice these wires together. Since you noted which wires went where, connect the hot, common or line wire to the black dimmer wire. The load house wire connects to the load dimmer wire, which is usually red. See the diagram that comes with the dimmer to confirm this.

Step 5) Test the Dimmer. Turn the power back on so that it runs to the switch. Try using the switch. If the light turns on, you’re in business. If the switch doesn’t work, the hot wire and the load wire may be reversed. Turn off the power to the switch and reverse the wires. The switch may also not work because the bulb is burned out or because you’re using a non-dimming CFL. Check for loose wires and for a bad bulb connection.

Step 6) Install the Cover Plate Gently tuck and fold the wires into the switch box. From there, press the electric dimmer into the box and install the mounting screws. Replace the plastic cover plate and secure it in place with finishing screws. Your electric dimmer should now be ready to go!