I'm trying to install a ceiling lamp in Canada and the lamp box has 3 insulated wires sticking out of it: black, red and white. I'm getting 120V between black and white and between red and white. I'm getting 0V between black and red. There's also an uninsulated wire inside the box and I'm assuming that's the ground.

There's a switch on the wall that's controlling the red/white combo. There's nothing controlling the black/white combo as far as I can tell. What's going on here?

The switch and box have never been used before since the house was built.

  • 1
    Are there any wires hooked up to that switch? What wires are in that switch box?
    – JACK
    Commented Apr 26, 2020 at 16:17
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    What used to be up there?
    – JACK
    Commented Apr 26, 2020 at 16:39
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    Regarding the switch, have you checked for switched outlets? Commented Apr 26, 2020 at 16:41
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    Broken/miswired switch? Or simply "rewired around switch because somoeone did not want the switch to work?" Poor attempt at a MWBC from the wrong type of breaker? The presence of the switch makes the first two options seem more likely.
    – Ecnerwal
    Commented Apr 26, 2020 at 17:43
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    That's a junction or light box, not a socket. Chances are it was wired for a ceiling fan and light combo, which explains the two hots. I'm not sure what the switch situation is. You haven't mentioned whether you've looked for switched outlets.
    – isherwood
    Commented Apr 28, 2020 at 16:50

1 Answer 1


Pictures of the inside of the fixture box and switch box would be nice to confirm this, but based on your description it sounds like the installer wanted to be able to put a ceiling fan in this location.
In my parents' house they have a lot of ceiling fans wired this way - the fan is always on (and controlled by a pull cord) while the light is controlled by the wall switch.
The purpose of this arrangement is to make it easy to turn the light on and off while leaving the fan alone.

Since you are putting in only a light fixture, you should cap the black wire with a wire nut. For safety to prevent the nut from coming off you can tape the nut onto the wire with electrical tape (after screwing it properly to the wire; do not rely only on the tape to hold it there).

After capping the black, you should be able to hook up your fixture like this:

  • fixture black to house red
  • fixture white to house white
  • fixture green to house bare ground

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