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I am replacing an old ceiling fan and combination switch in a bedroom in my house. I am trying to connect a new switch that controls both functions (fan and light) separately, as well as a dimming function for both. The previous fan (while unsightly), worked perfectly fine with the old combo switch. The top controlled the light, the bottom controlled the fan. Problem is, when I took the old fan off, and installed the new fan, there were only 3 wires coming out of the ceiling: load (black), neutral (white), and ground (bare). The new switch demanded two load wires (one for each function). I did not take a picture of the way it was wired beforehand (although i wish I had for the life of me). The point is, the ceiling fans were both wired the same way from the wires protruding from the ceiling itself.

In the electrical box, there are 3 sets of wires. From testing I have figured out that the two sets protruding from the bottom are both hot, and the single set of wires coming from the top are the load wires for the fan. The 3 neutral (white) wires were not all connected together originally, but the instructions for the new switch told me to do that. I cannot rewire the old switch to control both functions, a single switch just controls both. if i touch either of the two bottom hot wires to the load wire for the fan, both the light and fan come on and are steady.

I spoke with an electrician about it and he said I either needed a fourth wire or it had something to do with the break-away tab on the old combo switch. I am not trying to use the new switch anymore, I just want to understand how the thing was wired originally. THERE IS NO FOURTH WIRE. I have not added or removed any wires from the previous configuration with the exception that there may have been two wires spliced into one (from the remains of disconnecting the old switch there is about a 3-4 inch black wire by itself no longer connected or spliced to anything else), but like I said, I didn't take a picture of what it looked like beforehand. I am perplexed, please help.

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  • To control light and fan separately you need 3 wires. If you're positive there's only a black, white and bare copper then it sounds like they used the black, the white and the copper ground wire for the 3rd wire. That's not an acceptable way to wire the fan. – Platinum Goose Feb 19 '19 at 22:28
  • Has this recently become unacceptable? I believe the fan to be original to the house ~1973. Is it not up to code, hazardous, or just to protect electricians when working? To be safe and to code, will I need to have someone run another line? Thanks for your help. – Gavin Mitchell Feb 19 '19 at 22:34
  • One of the electrical experts should comment soon and they can answer your question better. If the fan is original someone may have added the switch at some later point and did the creative wiring. Another option is to get a remote control which will work with your existing wiring, the remote can control the light and fan separately. – Platinum Goose Feb 19 '19 at 22:48
  • Thanks, I was going to ask about a digital option, I'm sure that is much more straightforward. Thanks again. – Gavin Mitchell Feb 19 '19 at 22:58
  • Bootlegging ground was always unacceptable. Safety ground is for safety, and it's not insulated because it's never supposed to be hotter than ground. Bootlegging neutral from ground risks electrifying all the grounds in your house. But normally when someone installs a ceiling fan rated box, they also install the proper /3+gnd cable. This suggests another danger: that the ceiling box is not actually fan-rated. – Harper - Reinstate Monica Mar 22 '19 at 3:50
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Take your fan controller back and get a Lutron MA-LFQM instead

Most fan controllers on the market today are incompatible with your wiring configuration, where there is only one hot going up to the fan from the switch. However, there is one that's suitable, and that's the Lutron MA-LFQM. This uses a module in the fan canopy to decode a digital signal from the wall controller into separate fan and light outputs, and isn't too hard to find. (It also can use matching Lutron accessory controls for 3-way or 4-way work.)

Once you get the correct control in, you'll want to pick one of the bottom hot/neutral pairs and stick with it, capping the other incoming hot and neutral off individually. Once you do that, the control is wired according to the single-pole instructions, with the load neutral nutted to the remaining neutral, the line hot connected to the black screw on the control, and the load hot connected to a brass screw on the control.

At the ceiling fan, the canopy module is wired with its white neutral to the remaining neutrals (fan-neutral and incoming-neutral), its black to the incoming black (switched-hot), its red to the light kit wire off the fan (typically blue), and its yellow to the fan wire on the fan (typically black). Connect all the bare/green grounds (fan ground, box ground, incoming ground) together, button up both boxes, turn the breaker on, follow the control activation procedure in the instructions, and enjoy your fan!

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I think Platinum Goose has correctly guessed how this was originally wired: the white and the black wires were used as switched line/hot going to the fan and and light loads, and the bare wire was (mis-)used as the neutral. I've seen shenanigans like this once or twice when an electrician came up short by one conductor. It's true that this practice violates code requirements, and has for some time.

So, what to do from here? If the lights and fan must be controlled separately, there are two options:

  1. install more cable between the switch and the light/fan so that conventional wired control (or plain switches) can be used
  2. use a remote control solution. For example, Lutron (and other vendors) offers a nice ceiling fan controller which offers adjustable fan speed and light dimming from the control on the wall.

One other note: you wrote that "if i touch either of the two bottom hot wires to the load wire for the fan, both the light and fan come on and are steady." That does make it sound as if you have two separate hot sources coming into this box. That isn't inherently bad, but it is at least unexpected, and would be important to learn why this is the case.

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