How to install dimmer switches?

Rather than being limited to a simple on-off function for your lights, you can achieve a versatile range of lighting options by installing a dimmer switch. Most dimmer switches are thoughtfully designed to seamlessly fit into standard wall box openings, allowing for straightforward replacement of switches controlling incandescent or halogen lights with dimmers. In this guide, we will walk you through the process of installing a dimmer switch independently, and you’ll find that it can be completed efficiently in a relatively short span of time.

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Steps for installing dimmer switches

Here’s a step-by-step guide to help you install a new dimmer switch yourself.

Choose a suitable dimmer switch

The first step in mastering the art of installing a dimmer switch is selecting the most suitable type to meet your specific requirements. Dimmer switches not only allow you to fine-tune your lighting ambiance but also contribute to energy conservation. These switches come in a variety of colours and styles, offering a diverse range of options. When you embark on the journey of choosing a dimmer switch for your home, there are three crucial factors to consider:

Type of light: Dimmer switches are designed to work with particular types of lights, and selecting the correct dimmer switch is paramount in ensuring optimal performance. Using an inappropriate dimmer may result in issues like flickering, lights staying on or not functioning at all. For LED bulbs, it’s essential to opt for an LED dimmer, as LEDs operate on a DC current. LED bulbs are also compatible with smart dimmer switches. While CFL (Compact Fluorescent Lamp) bulbs will work with LED switches, it’s advisable to use CFL dimmers designed specifically for these bulbs. In most cases, incandescent and halogen bulbs are compatible with a wide range of dimmer switches. However, it’s still a good practice to choose either halogen dimmers or incandescent dimmers based on the type of bulbs you plan to use. Keep in mind that dimmer switches may not be compatible with all fluorescent lights, so it’s crucial to double-check that the dimmer switch is rated for the specific bulb you intend to use.

Number of switches: Dimmer switches come in two primary wiring configurations: standard single-pole dimmers and three-way dimmers. In a standard single-pole dimmer setup, a single switch controls the light. On the other hand, three-way dimmers enable you to control a light with two separate switches. For this setup, you will need a three-way dimmer and a three-way switch. This configuration allows you to dim the light from one location while turning it on and off from another. If your lighting arrangement involves only one switch controlling the light, then a single-pole dimmer is the appropriate choice. However, if two switches are responsible for controlling a single light or a group of lights, you will require a three-way dimmer.

Number of bulbs: Consider the total number of lights that will be connected to the dimmer switch and calculate their combined wattage. Verify that the dimmer switch you select can handle the total wattage to ensure it operates safely and efficiently.

Shut off power and remove old switch

To begin the process of installing a dimmer switch, follow these steps:

Start by turning off the power supply at the circuit breaker box. To ensure the power is indeed off, you can flip the current switch on and off or use a voltage tester that you know is working correctly to test the circuit. This step is crucial to prevent any electrical accidents.

Employ a screwdriver to carefully remove the existing wall plate and screws securing the switch to the wall box.

Gently pull the switch away from the wall. If you spot a cluster of white wires at the back of the wall box, you can leave them undisturbed.

For those replacing a three-way switch, take note of the wire attached to a screw that may have a different colour or is labelled as ‘COMMON’. It’s important to distinguish this wire from the one connected to the green screw, which is the ground wire. To make identification easier during the new dimmer wiring, mark the common wire with a piece of electrical tape.

Proceed to disconnect all wires from the old switch. If you’re replacing an existing dimmer, you will need to unscrew the wire nuts securing the switch wires and house wires.

Connect new switch

Next, proceed with connecting the new dimmer switch. Follow these instructions based on whether you are wiring a single-pole dimmer switch or a three-way dimmer switch:

Wiring a single-pole dimmer switch

If the house wires have bent ends, use a wire stripper to trim off these twisted portions. If necessary, remove about 3/4 inch of casing from the ends of both the house wires.

Take the ground wire from your dimmer switch and connect it to a green or bare copper wire within the wall box. Twist the ends together clockwise and secure them with a wire connector nut.

Now, join each dimmer wire (typically black) with a corresponding house wire. You may encounter house wires that are black, red, or white with black markings. Grasp the wire ends with pliers and twist them together. Use wire nuts to firmly cover each pair of wire ends. In case any bare wire is exposed, simply unscrew the wire connector, remove the wires, trim the ends with a wire cutter, and then re-cap the wires.

Wiring a three-way dimmer switch

If the house wires have bent ends, use a wire stripper to trim off these twisted portions. Remove about 3/4 inch of casing from both the house wires and the dimmer switch wires if necessary.

Take the ground wire from your dimmer switch and connect it to a green or bare copper wire within the wall box. Twist the ends together clockwise and secure them with a wire connector nut.

Connect the black dimmer wire to the tagged common wire, and remove any electrical tape used for identification.

Now, connect the two remaining dimmer wires, known as traveller wires, individually to the remaining wires within your wall box.

Finally, use a screwdriver to mount your dimmer switch securely to the wall using the provided screws.

Replace wall plate

Now, proceed to replace the wall plate by following these steps:

Carefully tuck the wires into the electrical outlet box, ensuring they are neatly arranged.

Tighten the screws that secure the dimmer switch to the electrical box, ensuring it is firmly in place.

If your dimmer switch includes a removable knob, gently pull it outward to detach it from the dimmer before attaching the wall plate.

In case the dimmer switch comes with a separate wall plate, tighten the mounting screws that secure the wall plate to the switch.

If you are using a wall plate with a screwless design, attach the wall plate adapter to the dimmer, then carefully snap the wall plate onto the adapter.

Turn on power

Now that you have successfully installed the wall plate, it’s time to restore the power:

Return to your circuit breaker box.

Switch the power back on to the circuit that controls the dimmer switch.

With the power restored, proceed to test the dimmer to ensure it is functioning correctly.

FAQs

Can you install your own dimmer switch?

Yes, most of the dimmers are designed to fit a standard wall box opening, making it easy to replace a standard light switch with a dimmer.

Do you need special wiring to install a dimmer switch?

No, if you're replacing a single-pole light switch with a light dimmer, the wiring remains the same as do the connections. Similarly, a three-way dimmer can replace a regular three-way switch without requiring additional wiring. The dimmer function is integrated into the switch.

Can you install a dimmer switch on any outlet?

Dimmers should only be connected to receptacles supplying lighting loads if the plug/receptacle combination is of a nonstandard configuration type that is specifically for such unique combinations.

Are LED lights dimmable?

Yes, LED light bulbs are dimmable.

Is it cheaper to use a dimmer switch?

Yes, dimmer switches not only provide lighting flexibility but also reduce energy consumption, resulting in cost savings on your power bill.

Are all light bulbs dimmable?

Not all light bulbs are compatible with dimmer switches. It's essential to ensure that both the switches and bulbs are compatible before installation.

How many wires does a dimmer need?

A dimmer typically requires three wires: white, black, and ground wire, which may be wrapped in green or bare copper.

Got any questions or point of view on our article? We would love to hear from you. Write to our Editor-in-Chief Jhumur Ghosh at jhumur.ghosh1@housing.com

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