With Valentine’s Day right around the corner, it’s the perfect time to get the lighting in your home ready for a romantic evening. Replacing old light switches with dimmer switches allows you to set the mood in a room, as well as helps save electricity and extend the life of your light bulb. Learn how to install one in your home by following the directions below.
Determine Wiring Configurations
Dimmers come in two basic wiring configurations: standard single-pole dimmers and three-way dimmers. According to The Home Depot, with a single-pole dimmer, a single switch controls a light. With a three-way dimmer, you can control a light with two switches. Before purchasing the dimmer switch, you need to know the number of switches that turn on and off the light. For example, if only one switch controls the light, purchase a single-pole dimmer. If two switches control a single light or a group of lights, you will need a three-way dimmer. To ensure your dimmer can handle the necessary wattage, calculate the total in your light fixture by adding up the bulb wattage. For example, three 60-watt bulbs in one light fixture mean the wattage for that fixture is 180.
Gather Tools & Turn Off Power
The tools you’ll need for this project include a screwdriver, wire stripper, inexpensive voltage tester and needle-nose pliers. To begin, turn off the power to your switch at the breaker and double-check for hot wires in the box. Confirm the power is off by flipping the switch on and off and make sure nothing turns on.
Remove Old Switch
Remove your existing wall plate by unscrewing the screws mounting the switch to the wall box. Carefully pull the switch away from the wall. According to The Home Depot, if you see a bundle of white wires in the back of the wall box, you can leave them intact, as you will not be using them. If you are replacing a three-way switch, one wire will be joined to a screw that is colored differently or labeled “COMMON.” Note that this is different from the wire joined with the green screw, which is ground wire. It’s recommended to tag the common wire with a piece of electrical tape to identify it when wiring the new dimmer. Be sure to remove all wires from the old switch. For a visual on how this might look, click here.
Add New Dimmer Switch
If you are adding a standard single-pole dimmer, you should join the ground wire from your dimmer to a green or bare copper wire in the wall box and twist the ends together clockwise and cap them by using a wire nut. The Home Depot recommends joining each dimmer wire (typically black wires) to a house wire (typically red or white wires with black marking) by gripping the wire ends with a pair of pliers and twisting them together. Tighten a wire nut over each pair of wire ends. If there is bare wire exposed, unscrew the wire nut, remove the wires, trim the ends of the wires with a wire cutter, and re-cap the wires.
If you are installing a three-way dimmer, you should join the ground wire from your dimmer to a green or bare copper wire in the wall box. Twist the ends together clockwise and cap them using a wire nut. Join the black dimmer wire to your tagged common wire and remove the electrical tape. Then, add the two remaining dimmer wires, called traveler wires, separately to each remaining wire in your wall box. Use a screwdriver to mount your dimmer to the wall with the provided screws.
Replace Wall Plate
The last step to installing a dimmer switch is to replace the wall plate. To do this, The Home Depot recommends carefully tucking the wires back into the electrical box and tightening the screws holding dimmer to the electrical box. If you’re installing a dimmer that has a removable knob, remove the knob from the dimmer by gently pulling outward before attaching the wall plate. If the dimmer is on a separate wall plate, tighten the mounting screws that hold the wall plate to the switch. If you’re using a wall plate with a “screwless” design, screw the wall plate adapter to the dimmer, and carefully snap the wall plate onto the adapter.
Once this is done, you can now turn the power back on at the breaker and test the dimmer.
TIP: Use WD-40® Multi-Use Product to help unstick light dimmer switches.
This was originally posted in February 2015.