How Do I Wire a Three-Function Control Switch?

Three-function switches are a great addition to any home, especially in bathrooms that have a bathroom fan and multiple lights.

These switches allow three separate electrical components to be wired to the same location. These switches are essentially three single-pole switches bundled together in a single switch, and are wired in the same manner as ordinary light switches, with the addition of common terminals to power and ground all the switches at once.

Turn off your bathroom's circuit breaker. If you are unsure which breaker is the bathroom's, turn off the main breaker.

Remove the cover plate over the old wall switches. Unscrew the old switches from the wall mounting box and remove the switch wires. Strip about 1/2 inch off the ends of the house's wiring and the three components to be connected to the switch. Each section of wiring, from the components and house, should contain white, black and bare copper wires. The bare wire is the ground.

Connect the first component's wires to the top switch. The component's white wire will connect to the neutral terminal, the black wire will connect to the switch's positive terminal, and the copper wire will connect to the ground terminal on the switch.

Connect the second component to the second switch, by connecting the component's white wire to the second switch's neutral terminal, the black wire to the positive terminal and the copper wire to the ground terminal.

Connect the third component to the remaining switch, by connecting the component's white neutral wire to the switch's neutral terminal, black wire to the positive terminal and copper wire to the ground terminal.

Connect the house's white neutral wire to the common neutral terminal on the switch, the black wire to the common positive terminal and the copper wire to the common ground terminal. Mount the switch to the mounting box.

Things You Will Need

  • Wire strippers
  • Screwdriver

Tips

  • Label the wires you disconnected from the old switches so you can match each set to the right connectors on the new switch.
  • The ground wire in some bathroom components may be a green wire instead of a bare copper wire.
  • Most three-function switches have holes into which you put the wires; use the screwdriver to help pop the wires into the holes. Some switches have screw terminals; use the screwdriver to tighten the screws after attaching the wires.
  • The new switch face may be a different size than old switches, so you'll need a new cover plate.

About the Author

Sean Farmer has been a professional writer since 2004. He has written many published works for various websites. Farmer is currently working towards a Doctor of Philosophy in psychology at Northwestern Oklahoma State University.