This article explains the detailed steps needed to wire a 3-way switch when the power source and the fixture feed on the same switch.
When wiring your 3-way switch, consider the following:
- At the ceiling box--the ungrounded conductor (a.k.a. hot) from the fixture connects to the black wire from the switch
- The white wire from the switch is the grounded leg conductor (a.k.a. neutral) for the fixture
- Wrap a piece of black electrical tape around both ends of the white wire going between switch box 1 and 2, as this wire is also being used as a ungrounded conductor (a.k.a. hot).
- Bare wires are together and grounded to box (if metallic) and if the fixture has a green wire or a grounding screw, it gets grounded also
- Bares and green wires are equipment grounding conductors
If You Need Onward Power From the Fixture:
If only switched power required onward then at existing fixture, then:
- Onward cable--black/white/bare
- Connect black from onward cable to the black coming from switch
- Connect white from onward cable to white wire coming from switch
- Connect bare from onward cable to other bares and to the electrical box if metallic
- At the onward cables destination, the black is the switched ungrounded conductor (a.k.a. hot), the white is the grounded leg (a.k.a. neutral), and the bare is the equipment grounding conductor
If only unswitched power required
onward then at existing fixture:
This is not possible with this configuration as there is no unswitched ungrounded conductor (a.k.a. hot) available at the fixture/ceiling box location.
If you need onward
power from the switch:Onward
power is only available at the switch 1 location as there is no grounded
leg {aka neutral} available at the switch 2 location. Instructions bellow
are based on the switch 1 location..
If Only Switched Power Required Onward Then at Switch 1:
- Onward cable -black/white/bare
- Connect black from onward cable to the black coming from switch 2
- Connect white from onward cable to white wire coming from circuit power supply cable
- Connect bare from onward cable to other bares and to electrical box if metallic
- At the onward cables destination, the black is the switched ungrounded conductor (a.k.a. hot), the white is the grounded leg (aka neutral), and the bare is the equipment grounding conductor
If Only Unswitched Power Required Onward then at Switch 1:
- Onward cable--black/white/bare
- Connect black from onward cable to the black coming from circuit power supply cable
- Connect white from onward cable to white wire coming from circuit power supply cable
- Connect bare from onward cable to other bares and to electrical box if metallic
- At the onward cables destination, the black is the ungrounded conductor (a.k.a. hot), the white is the grounded leg (a.k.a. neutral), and the bare is the equipment grounding conductor
If Switched and Unswitched Power Required Onward then at Switch 1:
- Onward cable--black/red/white/bare
- Connect black from onward cable to the black coming from circuit power supply cable
- Connect red from onward cable to the black coming from switch 2
- Connect white from onward cable to white wire coming from circuit power supply cable
- Connect bare from onward cable to other bares and to electrical box if metallic
- At the onward cables destination, the black is the unswitched ungrounded conductor {aka hot), red is the switched ungrounded conductor (a.k.a. hot) the white is the grounded leg (a.k.a. neutral), and the bare is the equipment grounding conductor

The Common Screw
of a 3 Way Switch is the Odd Color Screw
If wiring multiple fixtures be sure to check the following guidelines
concerning how to do it and what not to do: Wiring
Multiple Fixtures.
If you are new at understanding the "politically correct" electrical terminology
and need clarification of the terms used, we strongly urge you to read the Clarification
of Definitions and Terminology guide. This will explain the terminology
used in this article.