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Home > Switches & Outlets > Fan/Light Combo > 3-Way Switches, Power at Switch, 3-Wire plus Ground Cable Routed thru a Ceiling Box

Fan Light Switched Separately - 3-Way Switches, Power at Switch, 3-Wire plus Ground Cable Routed thru a Ceiling Box

By Donald Kerr
Fan Light Switched Separately - 3-Way Switches, Power at Switch, 3-Wire plus Ground Cable Routed thru a Ceiling Box

At the ceiling box - the ungrounded conductor {aka hot} from the fan connects to the black wire from the switch box 1(on the 2 wire + bare cable {black/white/bare cable}). The ungrounded conductor {aka hot} for the light connects to the red wire coming from switch box 2. The white wire from switch box 1(on the 2 wire + bare cable {black/white/bare cable}) is the grounded leg conductor {aka neutral} for both the fan and light. The red wire on the black/red/white/bare cable coming from switch box 1 is unused and just cap it off at both ends with a insulated wire nut. This will provide a switched ungrounded conductor {aka hot} for the fan and a switched ungrounded conductor {aka hot} for the light.

The reason for using a 3 wire + ground (black/red/white/bare) cable between switch box 1 and fixture (and not using the red wire) is to ensure that it will be easy to distinguish at the fixture the difference with the 2 cables coming from switch box 1 to help prevent the wrong two wires being connected. Using 2 wire+bares (black/white/bare) would make it more difficult to distinguish the 2 cables at the fixture and could end up with a dangerous combination of wrong wires being connected together.

Bare wires are together and grounded to box and if the fixture has a green wire or a grounding screw , it gets grounded also. Bares and green wires are equipment grounding conductors.

On the cable between switch box 1 and 2 , wrap a piece of black electrical tape around the white wire (at both ends) to indicate that this white wire is being redesignated and used as a ungrounded switch leg {aka hot}.

Be sure to read all documentation that comes with your fan / light combo fixture.


3 wire (plus bare) being routed thru the ceiling box onward to other switch

If you need onward power from the fixture then....

(1) If only switched power required onward then at existing fixture...

  1. onward cable - black/white/bare
  2. connect black from onward cable to the black (from switch box 1 on the 2 wire + bare {black/white/bare cable}) OR Red wire coming from switch2{depending onwhich switch(s) you want the onward switched power to be controlled from}
  3. connect white from onward cable to white wire coming from switch box 1 (on the 2 wire + bare {black/white/bare cable}).
  4. connect bare from onward cable to bares coming from switches and to electrical box if metallic.
  5. At the onward cables destination , the black is the switched ungrounded conductor {aka hot}, the white is the grounded leg {aka neutral} , and the bare is the equipment grounding conductor.

(2) If only unswitch power required onward then at existing fixture...
For this option to work , you must now make use of the spare unused red wire.

AT SWITCH BOX 1....

  1. The red wire (previously unused) on the 3 wire + bare (black/red/white/bare) cable (at switch box 1) connect to the black wire on the circuit power supply cable.

AT CEILING / FIXTURE BOX....

  1. onward cable - black/white/bare
  2. connect black from onward cable to the red wire on the 3 wire + bare (black/red/white/bare) cable coming from switch box 1
  3. connect white from onward cable to white wire coming from switch box 1 (on the 2 wire + bare {black/white/bare cable}).
  4. connect bare from onward cable to bares coming from switches and to electrical box if metallic.
  5. At the onward cables destination , the black is the ungrounded conductor {aka hot}, the white is the grounded leg {aka neutral}, and the bare is the equipment grounding conductor.

(3) If 2 separately switched power is required onward then at existing fixture...

  1. onward cable - black/red//white/bare
  2. connect black from onward cable to black wire coming from switch box 1(on the 2 wire + bare {black/white/bare cable}).
  3. connect red from onward cable to the red wire coming from switch box 2.
  4. connect white from onward cable to white coming from switch box 1 (on the 2 wire + bare {black/white/bare cable}).
  5. connect bare from onward cable to bares coming from switch and to electrical box if metallic.
  6. At the onward cables destination , the black and red wires are separately switched ungrounded conductors {aka hots}, the white is the grounded leg {aka neutral}, and the bare is the equipment grounding conductor.

If you need onward power from the switch then....

NOTE: In regards to the switch box locations - in this configuration onward power is only available at switch box 1. Switch box 2 has no grounded leg {aka neutral} and therefore onward power is not possible at switch box 2. Descriptions bellow are based on switch box 1 location...

(1) If only switched power required onward then at existing switch...

  1. onward cable - black/white/bare
  2. connect black from onward cable to either of the following wires {but not both}... [aa] pigtailed to the black wire going between switch box and fixture (on the 2 wire + bare {black/white/bare} cable) [bb] pigtailed to the red wire (previously unused on the 3 wire + bare (black/red/white/bare) cable)

If you used the red wire then at the fixture/ ceiling box end , that red wire needs to be connected to the red wire coming from switch box 2. The choice will depend on if you want the onward switched power to be controlled by one switch at one location or by the 3 way switches at the 2 locations.

  1. connect white from onward cable to white coming from circuit power supply cable.
  2. connect bare from onward cable to other bares and to electrical box if metallic.
  3. At the onward cables destination , the black is the switched ungrounded conductor {akahot} , the white is the grounded leg {aka neutral}, and the bare is the equipment grounding conductor.

(2) If only unswitch power required onward then at existing switch...

  1. onward cable - black/white/bare
  2. connect black from onward cable to black from the circuit power supply cable.
  3. connect white from onward cable to white circuit power supply cable.
  4. connect bare from onward cable to other bares and to electrical box if metallic.
  5. At the onward cables destination , the black is the ungrounded conductor {aka hot}, the white is the grounded leg {aka neutral}, and the bare is the equipment grounding conductor.

(3) If switched and unswitched power required onward then at existing switch...

  1. onward cable - black/red//white/bare
  2. connect black from onward cable to black circuit power supply cable.
  3. connect red from onward cable to either of the following wires {but not both}... [aa] pigtailed to the black wire going between switch box and fixture (on the 2 wire + bare {black/white/bare} cable) [bb] pigtailed to the red wire (previously unused on the 3 wire + bare (black/red/white/bare) cable)

If you used the red wire then at the fixture/ ceiling box end , that red wire needs to be connected to the red wire coming from switch box 2. The choice will depend on if you want the onward switched power to be controlled by one switch at one location or by the 3 way switches at the 2 locations.

  1. connect white from onward cable to white circuit power supply cable.
  2. connect bare from onward cable to other bares and to electrical box if metallic.
  3. At the onward cables destination , the black wire is the unswitched ungrounded conductor {aka hot},red wire is the switched ungrounded conductor {aka hot} , the white wire is the grounded leg {aka neutral}, and the bare wire is the equipment grounding conductor.

(4) If 2 separately switched power is required onward then at existing switch...

  1. onward cable - black/red/white/bare
  2. connect black from onward cable to the black wire going between switch box and fixture (on the 2 wire + bare {black/white/bare} cable)
  3. connect red from onward cable to the red wire (previously unused on the 3 wire + bare (black/red/white/bare) cable) At the fixture/ ceiling box end , that red wire needs to be connected to the red wire coming from switch box 2.
  4. connect white from onward cable to white coming from circuit power supply cable.
  5. connect bare from onward cable to bare coming from circuit power supply cable and to electrical box if metallic.
  6. At the onward cables destination , the black and red wires are separately switched ungrounded conductors {aka hots}, the white is the grounded leg {aka neutral}, and the bare is the equipment grounding conductor.{red being controlled by the 3 way switches at 2 locations, and the black being controlled by 1 switch at 1 location}

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.

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