Unfortunately I did not take a picture of how the original fan was wired, but I have 5 wires going to the fan, and the fan appears to have connections for 7, help?

Schematic: enter image description here

Wires to the unit: enter image description here

Unit's wires: enter image description here

3 control switch- light, fan, heat enter image description here

enter image description here enter image description here

I'm sure that previous fan had exhaust, heat, and light working independently, but again I did not have the foresight to take a picture of that before removal. My dad says it's not possible, am I crazy?


To wire this properly, you have two options.

  1. Run a 14/4 (or 12/4 if it's a 20 ampere circuit), or 14/2/2 (12/2/2 for 20 amperes) plus ground nonmetallic sheathed cable (Type NM) between the switch and the fan.
  2. Install conduit and run individual conductors between the switch and fan.

There's no way to wire this in a code compliant way, using two 14/2 with ground cables. You'd either violate 300.3(B), by not having all the conductors in the same cable. Or you'd violate 310.10(H)(1), by having paralleled conductors.

Using 14/4 is the easiest, since the wire colors should match up. Simply collect all the white wires from the fan, and connect them to the white wire from the 14/4 cable. Connect the bare ground wire from the cable, to the green wire from the fan. Then just match the colors, black to black, red to red, and blue to blue.

At the switch, connect all the grounds together. Connect the white wire from the 14/4 cable, to the feeder neutral. Connect the black wire to the fan switch, the blue wire to the light switch, and the red wire to the heater switch.

If you're using 14/2/2. Instead of a blue wire, you'll have a white wire with a red stripe. You'll have to mark this wire at both ends with a marker or tape, to reidentify it as a hot conductor. Once that's done, simply substitute it for the blue wire in the description above.

If you install conduit, you can use whatever code compliant color wires you want.

  • Makes sense, 2 follow ups: is this what you mean by 14/4:homedepot.com/p/… And can I use the ground wire from the existing wires?
    – jriggs
    Sep 15 '16 at 14:52
  • 1
    No, that's type SOOW cord. You'll want a nonmetallic sheathed cable (commonly called Romex®), but you might have to go to an electrical supply shop to get it. The new cable will have a ground wire included, so there's no need to use the ground wires from the existing cables. You can just rip out the existing cables, as you'll no longer need them.
    – Tester101
    Sep 15 '16 at 15:52
  • 1
    14/2/2 NM cable might be easier to find.
    – Tester101
    Sep 15 '16 at 15:56

Your dad's right from a legality standpoint. You have two hots available (the black wires), which means you can switch two components (or groups of components) separately.

That is, however, unless one of the white wires is acting as a hot. In that case, you have a "shared neutral" (the other white wire, in a different cable group from the first), which isn't strictly legal, and you have the ability to control three components.

An even more far-fetched scenario is that the bare ground wire was acting as a neutral for all four insulated wires, which could technically work but is illegal and dangerous.

You've probably noticed that you actually have six wires at the fan box. There are two grounds, one of which has been clipped short. It's modern practice to connect grounds in most scenarios rather than clipping them, or at least to simply tuck them away for future use. If you ever replace the switches, the new ones are likely to have ground screws or pigtails.

  • I think you're right about the ground being clipped.How would I wire it using the shared neutral/hot-white scenario you described?
    – jriggs
    Sep 15 '16 at 12:53
  • I squirm a little to go down that road, but you essentially send a white out from the switch as a hot, and use the other white as the neutral. If you don't grasp what that means you should probably get some professional assistance.
    – isherwood
    Sep 15 '16 at 13:21
  • I don't follow but Im sure if you gave a rundown of what wires connect to what, or a simple diagram I could figure it out. Everything is connected to a modern breaker box so I feel the risk is low
    – jriggs
    Sep 15 '16 at 13:56

All the whites connect together in this setup, blue goes to light, black goes to fan, red goes to heater.

  • This fails to take into account the fact that two 14/2s can't be legally used to supply 3 hots + 1 neutral (300.3(B)/310.10(H) violation) Dec 20 '19 at 0:31
  • Hello, and welcome to Home Improvement. Thanks for the answer, but it may be problematic. And, you should probably take our tour so you'll know how best to contribute here. Dec 20 '19 at 2:38

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