Dual Circuit Ceiling Fan

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Old 11-24-20, 10:43 AM
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Dual Circuit Ceiling Fan

The rooms in my house all have dual circuit ceiling fans. Not sure if that is correct terminology........one switch for fan, one switch for light.

The livingroom fan did not have a light on the fan so I'm replacing that unit to get some light in the room. When I pulled the old fan out and checked voltage on the two circuits, one doesn't seem to work. The black wire operates properly on the switch. 120 with switch on.
The red wire has about 42 volts on it no matter what position the switch is in. And I measured the same voltage on both sides of the switch.

So, it seems I have two problems. I have a shorted switch which I get. Any explanation why I'd have only 42 volts on that circuit other than a bad connection somewhere?
 
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Old 11-24-20, 11:29 AM
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Hi, so you a have 2 gang box with 2 switches, one for the fan and one for the light, in the ceiling fan box you must have a black ,red and white from the switch , correct? where are you measuring this 42 volts?
Geo 🇺🇸
 
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Old 11-24-20, 12:55 PM
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Yes, two gang box with two switches.
Yes, black and red from the ceiling. Here is the old fan wiring. Why would the old fan have two black wires if there was no light?

I measured 42V at the ceiling lead. Then, I went to the switch and measured it on both the input and output.
 
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Old 11-24-20, 03:49 PM
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"Why would the old fan have two black wires if there was no light?"

Many ceiling fans are sold as a fan only and the light is a separate option but the wiring is in the fan for the light. One black wire may be for the fan and the other for the light which your old fan didn't have installed. On most modern fans they use different colored wires in addition to labels on the wires.
 
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Old 11-24-20, 07:02 PM
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In the picture there is a black wire from the fan for the fan.
The black w/white stripe wire would have been for the light...... had it been installed.
 
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Old 11-25-20, 05:55 AM
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My guess is the 2 wires in the yellow wire nut, the white wire with red marking and the black wire, are an open circuit, not connected on either end. The 42 volts you are measuring is being magnetically induced somewhere along its length but can't provide power. The voltage should go to zero if you touch the black wire, identified above, to the bare ground wire at the ceiling box.
 
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Old 11-25-20, 06:18 AM
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The black wire from the ceiling is a good circuit..........it had 120V on it and operated with the switch. So I could just forget about the other (red) circuit and wire both to the black and run it off of a remote...........which is what I want. But it would be nice to fix the other circuit and not just leave it dead.

The red wire had continuity from the bottom of the switch to the ceiling, so that wire is good. Just not getting power to the top of the switch for some reason.

Do I just start going to nearby receptacles to find the source of power for that red wire to the switch?
 
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Old 11-25-20, 04:50 PM
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The red wire had continuity from the bottom of the switch to the ceiling, so that wire is good. Just not getting power to the top of the switch for some reason.
Since that is a three wire cable at the fan...... the red and black share a common neutral.
That means both switches are fed from a common hot.
Since the fan switch is working.... the hot connection to the red wire switch is open.
You should be able to see a common hot link between switches.

If not.... post a picture of the wiring in that switchbox.
 
 

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