Do it yourself - How to install a Dimmer Switch.
Wiring Home > Electrical > Switches and lighting > Dimmer Switches
Installing dimmer switches in your home is an easy and inexpensive improvement that will allow you to create nice mood lighting in any room. These switches come in a verity of styles and sizes; the size is determined by the amount of wattage that it is rated to control. Using the right size dimmer is very important and is common mistakes are made. If you beak off the tabs on the switch it makes the heat sink smaller and reduces the amount of wattage it can handle. The instructions that come with the switch should give you the rating information for your specific switch. For example if you break off too many you could easily purchase a 1000 watt dimmer switch that is only good for 600 watts.
It is also important to remember that you cannot use a dimmer switch on a florescent fixture unless a dimming ballast is installed in the florescent fixture prior to installing the switch.
How to figure out what size dimmer you need.
Simply multiply the number of lamps you are going to control by the wattage rating of each lamp.
Example: 10 lamps x 60 watts = 600 watts
With the example above you could get a 600 watt dimmer and max it out, a better solution would be to get a slightly larger dimmer. It will run cooler and not be pushed to the max, a good rule of thumb would be to use only 80% of what the switch is rated for.
What kind do you need?
As long as it will fit where you a putting it the style is up to you. What you need to find out is if it’s a single pole switch, a three way switch or a four way switch. If the fixture or fixtures are controlled from a single location you need a single pole dimmer, if they are controlled from two locations you will need a three way switch, if they are controlled by more three locations than you could need a three way or a four way switch depending on which switch you want to be the dimmer. If you want a dimmer at each location you will need one four way and two three way switches.
Dimmer Switch Styles
Make sure you turn the power off and measure your existing electrical switch box to make sure the new dimmer will fit in the box before you make your purchase.
Caution: To prevent severe shock or electrocution always turn the power OFF at the service panel before working with wiring.
Never Assume the power is off! Always double check, and test the device before you begin work.
How to change the switch.
1) Turn the power off to the circuit.
2) Remove the old switch.
3) 3) Connect the wires from the old switch to the new dimmer using wire nuts as the diagram illustrates.
Note: If one of the wires going to the old switch is white you will still make the connections the same way.
Don't disconnect the wires on the old switch until you are sure what each one is.
It is basically done the same way as the single pole with the addition of a wire that is very important. The Common wire, on normal three way switches the common terminal is usually colored black, but some manufactures may use a different color. This wire needs to be removed from the old switch and connected to the common on the dimmer usually it will be a red wire. The other two are connected to the black wires. If you do not know what the common on the old switch is will need to meter the switch to figure it out.
Tip - Use colored tape of something to mark the wires and what terminals on the existing switch before you disconnect the wires.
If you are going to replace a four way switch I would strongly recommend you use a meter to check the switching of the old switch verses the switching of the new switch. Some four ways close the connection vertically using the same screws on the same side, while some others may close horizontally using the two screws that are across from each other as the closure.
When you have multiple switches controlling the same lights you only need to replace one of the switches for your dimming to work, unless you want the convenience of being able to dim from each location.
If you are having problems, Play it Safe.
Make sure you check the regulations in the National Electrical Code regarding the device you are wiring. If you are still unsure of how to properly wire the circuit you are working on, you will need to contact
a qualified electrician in your area. You can also ask questions in our forum.
Single Pole Switches >
Three Way Switches >
Four Way Switches
> Dimmer Switch Styles
Related Resources: National Electrical Code Handbook
National Electrical Codebook
Stallcup's Illustrated Code Changes
The Complete Guide to Home Wiring (Black and Decker Complete Guides Series)
Guide to Using the National Electrical Code
Residential Remodeling and Repair Professional Reference
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