Wiring 3 Way Switches and Dimmer Switches
How are 3-way switches wired? The Key to Wiring 3 Way Switch and 3 Way Dimmer Switch Wiring, Wiring Configurations for 3 way Switch Wiring.
3Way Dimmers and 3Way Light Switches
Electrical Question: How are 3-way switches wired?
- I have a rotary dimmer switch that I am making a regular three way switch with 12 gauge wiring.
- I have one 12-2 leg from a switch coming to the dimmer, then the dimmer switch has four wires on it; two red, one black, then ground; and then a 12-3 wire coming down which I am traveling to the a normal three way switch and then powering my lighting off that switch.
- Now the wiring for the dimmer switch I don’t know where to wire them to.
All together in that dimmer I have three black, two red, two neutral, and three ground.
I am confused, can you please help?
This electrical wiring question came from: Andrew, a Handyman from Tower City, Pennsylvania.
Thanks for your electrical wiring question Andrew.
How to Wire 3Way Dimmers and 3Way Light Switches
Application: Wiring 3Way Light Switches.
Skill Level: Intermediate to Advanced – Best installed by a Licensed Electrician.
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 working with the wiring.
Notice: Installing additional 3-way switch wiring should be done according to local and national electrical codes with a permit and be inspected.
Materials: Make sure replacement 3-way light switches have the same amperage and voltage rating as the original three way light switch, and is the switch is fully compatible with the electrical circuit, the light fixture and the type of light bulbs being used.
The Most Common Mistake When Replacing 3 Way Switches
One of the biggest problems that occurs when replacing 3 way switches is when the existing switch is removed before identifying the wiring and taking too many wire connections apart.
Three way switch wiring for a dimmer and a standard 3 way switch is the same except that the dimmer switch has a set of wires and not terminal screws to make up the wiring.
The Key to Wiring 3 Way Switch and 3 Way Dimmer Switch Wiring
Question about Wiring 3-Way Switches: I understand how to wire a single pole or 3 way switch, but I am having trouble replacing a single pole and adding a 3-way switch.
- In my unfinished basement I have one switch at the bottom of the stairs controlling 7 light in various rooms.
- I want to replace this switch with a 3 way and add the other 3 way next to the outside door a distance away.
- I have strung 12-3 from the existing switch to the door (about 100 feet). Now how do I wire the two together?
This electrical wiring question came from Wally, a Homeowner, in Newman, Georgia.
NOTE: There are only three connections for both the 3 Way Dimmer and the 3 Way Switch.
- The Power In or Power Out
- The Dimmer Power is typically the Black Wire.
- The Switch Terminal is typically the single screw terminal at one end of the switch and is usually a Black Screw.
- The Two Travelers (or Jockeys-electrician terminology)
- The Dimmer Travelers are typically the two Red Wires.
- The Switch Travelers are typically the two screw terminals at one end of the switch and are usually brass.
- The Ground Wiring is typically a green insulated wire on the dimmer switch and green or bare copper wire in the switch boxes and they bond together and a pigtail wire is attached to the green ground screw on the 3 way switch frame.
Wiring Configurations for 3 way Switch Wiring
- 3 Way Wiring Configurations
- There are several wiring configurations that are used for 3 way switching which include the Power In, the Switched Leg Out to the light fixture(s), the two Travelers and of course the Ground wires.
- Other Cables in the Switch Box
There are also other cables that may be found and need to be identified, such as:
- Power Out to another light fixture switch or wall outlet.
- Additional cable(s) that may lead to additional light fixtures that are controlled by the three way switching. These cables are most always found in the same switch box location.
- Additional Power Cables include a hot, neutral and ground wire.
- White Wires and Neutral Wires
- IMPORTANT: Neutral Wires are not used in standard 3 way switching, however it should be understood that White Wires may be used for the 3 way switching configuration but that does not mean that they are neutral wires, in fact they should be identified with black or red electrical tape when a white wire is used for the purpose of power switching.
When the wiring has been taken apart or the configuration is unknown the electrician should start by using a voltage tester to identify all of the cables with regard to the key connections as described above.
Please Note: These are typical connections for standard 3 way switches. This does not apply to wireless dimmer switches and some Lutron Light Switches.
More about Wiring 3 Way Switches and Dimmer Switches
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.
Wiring a Light Switch – Diagram 1
Fully Explained Light Switch Wiring Diagrams. Detailed Electrical Wiring Diagrams and Pictures assist your Home Electrical Projects.
How To Wire 3-Way Switches Video
Electrician Explains Electrical Contractor Explains the basics of wiring 3 Way Switches for your home light fixtures
Electrical Switches: Wiring a 3-Way Switch
Electrician Explains the Basics of Wiring 3-Way Switches
Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.
The Safest Way to Test Electrical Devices and Identify Electric Wiring!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, [amazon.com], I use for the detection of Standard 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.
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