Remodeling a bedroom in a 1980s townhome. The home was set up with switched outlets and no ceiling lighting in most rooms. The bedroom in question does have 12/3 cable w ground to the ceiling from the switch box, but my parents are set on having a fan without a light in that location. In essence, the red cable isn't being used for the fan, and we'd like to get light to a different ceiling location. I have access to the fan j box from both below and the attic space, but the 12/3 cable is tied to studs and run through ceiling joists, so I cannot pull new lines from the switch without tearing apart walls/ceilings.

My question is whether or how I might try to jump off of this unused red(hot) for a second ceiling fixture. The switch box has room for another switch; it currently has a switch for the outlets, the fan switch, and an empty space, as the old fan had the light and fan switched separately. For the new light, can I just run 12/2 w ground to the new light location from the fan j box, attaching black to red and white to other whites. I guess I'm not sure if it's okay to run two separate fixtures off of the 12/3 of the fan like that, or if it would even work.

I can figure out a smart switch fix on another circuit from the attic, but I'd prefer everything be hard wired and on the same circuit. Any thoughts would be appreciated.



  • What kind of fan box are we talking about here, and is the 12/3 the only cable running into it, or are there other cables there already? Jan 5, 2020 at 15:52
  • The 12/3 is all that's there outside of the fan wires. The fan box is a 4" circular box with arms extended between the joists. I hadn't thought about box fill; I'll have to check its depth and do some calculating. I think I would have to destroy the box to remove it without messing with drywall.
    – Chris S
    Jan 6, 2020 at 16:33
  • The box should have a cubic inch measurement stamped into it, even though it may be hard to read; if you tell us the depth of the box, we'll be able to tell pretty much straight away if it's going to have enough room for the added cable or not though Jan 6, 2020 at 23:14

1 Answer 1


Yes, providing there is enough capacity in the j-box, you can just run 12/2 w ground to the new light location from the fan j box, attaching black to red and white to other whites.

12 awg requires 2.25 cu in per insulated conductor, plus adding one conductor to the count for all grounds. The fixture wires from the fan don't count.

  • The answer I would have written. +1 Jan 5, 2020 at 18:08
  • Thank you. I'll have to measure the box and plan accordingly.
    – Chris S
    Jan 6, 2020 at 16:35

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