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I'm trying to replace a ceiling fan and am struggling to understand how to update the wiring inside the ceiling box.

  • Both the old and the new ceiling fans include a light.
  • The old fan accepted separate wires for the light and fan motor.
  • The new fan only accepts a single wire that powers both the light and the fan motor.
  • The room has a single wall switch that controlled the old fan light. To control the old fan motor, we used a pull chain that was directly on the fan.

Here's a diagram to illustrate:

                                   common neutral

                                        │ │
                                        │ │
                                        │ │
┌────────┬──────┐            white      │ │     white          ┌──────────┬────┐
│        └──────┼───────────────────────┘ └────────────────────┼──────────┘    │
│    cable 1    │                                              │   cable 2     │
│        ┌──────┼───────────────────────┐ ┌────────────────────┼──────────┐    │
└────────┴──────┘            black      │ │     black          └──────────┴────┘
                                        │ │
                                        │ │
                                        │ │
┌────────┬──────┐            white      │ │
│        └──────┼─────────────────────┐ │ │
│     cable 3   │                     │ │ │
│        ┌──────┼────────┐            │ │ │
└────────┴──────┘        │            │ │ │
                   black │            │ │ │
                         │            │ │ │
                         │
                         │        to old fan motor
                         │     

    │    │       to old fan light
    │    │
    │    │
    │    │
 ┌──┼────┼──┐
 │  │    │  │
 │          │
 │   wall   │ controls old fan light
 │  switch  │
 │          │
 └──────────┘

If the diagram is unclear, here's a photo.

I'm trying to wire up the new fan, which only accepts a single hot wire. Overall power to the new fan is controlled by a simple wall switch, and a wireless remote is used to control the light intensity and fan speed.

The wall switch is presumably connected to cable 3, since it controls the light. But I don't know what to do with cables 1 and 2. Do I just use cable 3 by itself, and leave cables 1 and 2 in a state of holy matrimony, connected to each other and nothing else?

Also, can someone explain how power was flowing through the old fan? I don't get why the white wire from cable 3 was connected to the black wires from the other two cables. I assume it's because of how the light and fan motor are wired together inside of the old fan.

5
  • Because the white wire was not properly re-identified as a hot wire. This is a switch loop. Yes, the cheaper fans these days use wireless remotes. Dec 21, 2021 at 23:01
  • Can you post photos of the inside of the existing box please, as well as the make nad model of your new ceiling fan? Dec 22, 2021 at 5:29
  • @ThreePhaseEel - In the edit to my question I added pictures of the ceiling box as well as the section of the manual showing how to install the new fan's wall switch. I don't have the make/model handy at the moment. Dec 22, 2021 at 23:02
  • @NickChammas -- what do you want the wall switch to do with the new fan? Dec 23, 2021 at 1:35
  • 1
    @ThreePhaseEel - I want the wall switch to be a master on/off switch for the fan. I believe that's the intended setup shown in the image from the manual. The wireless remote (which I think mounts magnetically over the switch) will do the fine-grained control of turning the light or fan on/off and controlling the fan speed. Dec 23, 2021 at 14:09

1 Answer 1

1

What does the new unit's instructions say about how to control it?

Assuming, from your description, that it is either on or off, fan and light together on or together off: the new unit will have a black or live connection and a white or neutral one. Connect the wire with the blue tape to the "black", the two white wires to the "neutral" and the bare wire to the device's ground. The three wires twisted together should be left together and wire nutted but not connected to the device. Then your wall switch will turn the whole thing on or off.

I'm not 100% sure from your added picture how the remote works. It appears as though 1) it comes with a "master switch" that replaces your existing light switch 2) you wire your light as I described above, powering it from the switched live, 3) it includes a battery operated, wireless remote that mounts cleverly in front of the master switch and controls the light and fan and 4) the master switch is generally left On, and is meant to be used probably only if the batteries die in the remote and you need to turn the thing off.

To answer your how/why question: What you call "cable 3" goes to the wall switch. The white wire sends power to the wall switch, and if it's switched on, the black wire in that cable, with the blue tape, provides power to the light. That black wire is called "switched live". The other black wires are live, and they ALSO provided power to the fan, controlled by the chain but your new gadget doesn't have that capability so you just have to leave those three wires connected to each other and cap them off. Cables 1 and 2 bring power into this box and deliver it to the next box, ie a receptacle or light in maybe another room.

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  • I've updated my question with a photo of the new fan's switch/remote. Dec 21, 2021 at 19:10
  • So power is flowing through the black wires of cables 1 and 2, and thus also through the white wire of cable 3, down to the wall switch. When I flip the wall switch, that power then flows up cable 3's black wire to the ceiling unit, powering the light, and returns via the white wires on cables 1 and 2. The old fan motor was always powered on because power flowed from the black wires of cables 1 and 2, though the fan, and then back via the white wires of those same cables. Did I get that all right? Dec 21, 2021 at 19:16
  • Exactly. The way Cable 3 is used is called a "switch loop". I'll add to my answer about the new picture of the remote.
    – jay613
    Dec 21, 2021 at 19:17
  • I believe the remote works as you described (per your updated answer). Thank you for your help. I'm accepting this answer and will return here if things don't go as expected. Dec 21, 2021 at 22:54
  • 1
    As long as you're fixing this up: It's customary (and perhaps required, I'm not sure) to use the wires in the switch loop the other way. The black wire should be connected to the other two black wires. The white wire should have a piece of black tape on it, and you use that to power your new device. You might want to fix that as long as you're working in there. At the switch you don't have to change anything .... it then becomes obvious to anyone working in there that the black, as always, is hot, and the white, since it's the only other wire, is a switched hot.
    – jay613
    Dec 22, 2021 at 1:07

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