How to Replace a 3 Way Switch with a 3 Way Dimmer Switch

How to Wire 3Way Dimmer Switches: Common 3Way Dimmer Switch Wire Connections and Light Level Adjustments, Wiring Two 3Way Dimmer Switches. By: Dave Rongey

Guide for Wiring a 3 Way Dimmer Switch
Electrical Question: I replaced the switch that we use most often with a dimmer switch. Now the switch that does not have the dimmer has to be on in order for the dimmer switch to work.

• I just bought a house that has 2 switches that control my living room light.
• I replaced the switch that we use most often with a dimmer switch.
• Now the switch that does not have the dimmer has to be on in order for the dimmer switch to work.
• When the lights are on they make a buzzing noise that they did not make before with the normal switch. Now, both the old switch and the dimmer switch have 3 posts.
• Looking toward the switch the top right has the black wire, bottom right has white wire, and left side has a red wire (on the dimmer switch).
• I just took the wires off the old switch and put them on the dimmer switch just the way they were. Did I do something wrong?
• The light works and dims but both switches have to be On, and now the On position is when the dimmer switch is down. The dimmer switch has a sliding control.

Thanks!

This electrical wiring question came from: Robert, a Homeowner from Gloucester, Virginia.

Dave’s Reply:
Thanks for your electric wiring question Robert.

How to Wire a 3Way Dimmer Switch

Application: Wiring for a 3Way Dimmer Switch.
Skill Level: Beginner to Intermediate. This electrical work is best performed by a Licensed Electrical Contractor.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester.
Estimated Time: Depends on personal level experience and ability to work with tools.
Precaution: Identify the lighting circuit, turn it OFF and  Tag it with a Note before wiring the new dimmer.

3Way Dimmer Switch Wire Connections

• Wiring Two 3Way Dimmer Switches
  
  • This is a relatively easy fix where the wiring at the dimmer switch is out of sequence, which can be caused by having a traveler wire connected to the point position.
  • In this case simply swap the single point wire with one of the two traveler wires at the opposite end of the switch.
    • NOTE: The Point Wire is commonly the Black Wire on a 3way Dimmer Switch, and the Black Screw on a 3Way Switch.
• Dimmer Switch Wiring Connections
  
  • The wiring may be corrected by identifying the point wire or the pair used for travelers and correcting the connections, which are shown in the 3 way dimmer switch wiring diagrams available below.
• Dimmer Switches Can Cause Lamps to Buzz
  
  • The buzzing that you hear when using the dimmer switch is coming from the filament inside the lamps which is vibrating at the lower control settings of the 3-way dimmer switch.
• Adjusting the Light Level of the Dimmer Switch
  
  • Most dimmer switches have a small adjustment which is located on the top area of the switch, close to the mounting bracket.
  • The cover plate will need to be removed to have access to the adjustment screw on the dimmer switch. Using a small screw driver, make the adjustment so the lights are barely on when the dimmer switch is in the lowest setting.
  • This adjustment will allow the dimmer switch to operate to the lowest setting and have full range of the dimmer  switch.

More about Wiring a 3Way Dimmer Switch

Wiring a switch

Wiring a Light Switch – Diagram 1

Wiring a dimmer switch

• 3 Way Dimmer Switch Wiring Diagram
  • Fully explained 3 way dimmer switch wiring diagram will take the mystery out of wiring a 3-way dimmer switch.

See More information about 3 Way Switch Diagram
3 Way Switch Diagram

• 3 Way Switch Diagram
  • In response to the requests for this information, I have developed a comprehensive,step-by-step guide designed to walk you through the identification and wiring of your 3-way switches.

The following may also be helpful for you:

Dave's Guide to Home Electrical Wiring: » You Can Avoid Costly Mistakes! « Here's How to Do It: Wire It Right with the help of my Illustrated Wiring Book Great for any Home Wiring Project. Complete Guide to Home Electrical Wiring Perfect for Homeowners, Students, Handyman, Handy Women, and Electricians Includes: Wiring GFCI Outlets Wiring Home Electric Circuits 120 Volt and 240 Volt Outlet Circuits Wiring Light Switches Wiring 3-Wire and 4-Wire Electric Range Wiring 3-Wire and 4-Wire Dryer Cord and Dryer Outlet How to Troubleshoot and Repair Electrical Wiring Wiring Methods for Upgrading Electrical Wiring NEC Codes for Home Electrical Wiring ....and much more. Learn more about Home Electrical Wiring with my Online Video Course: Basic Home Electrical Wiring by Example

Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.

Electrical Tips to Help You Wire it Right The Safest Way to Test Electrical Devices and Identify Electric Wires! The Non-Contact Electrical Tester This is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use. The Quickest Way to Check for Faulty Electrical Wiring! The Plug-In Outlet Tester This is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring. It detects probable improper wiring conditions in standard 110-125 VAC outlets Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency Lights indicate if wiring is correct and indicator light chart is included Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect Very handy and easy to use. Strip Off Wire Insulation without Nicking and Damaging the Electric Wire! The Wire Stripper and Wire Cutter My absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires. This handy tool has multiple uses: The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation. The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets.. The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use.

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