Wires in ceiling wall switch get thermally warmer when fan is off

Thread Starter

Lumenosity

Joined Mar 1, 2017
465
I have a ceiling fan which I believe someone wired improperly and I'm trying to figure it out.

I have a budget thermal camera and when the ceiling fan is switched OFF, the wires get warmer (100F)
Below is a thermal photo of the wall switch (not the dimmer, which is above it). You can see the warm wires.
The wires get progressively cooler the higher I turn up the fan speed. (Less resistance?)
So the dimmer appears to be acting as a resistor. (I guess that what dimmers do?)

Who ever installed the ceiling fan tapped in a Dimmer getting power and ground etc from the switch below it, to control the fan speed that they piggybacked onto the existing On/Off light switch.
But I suspect they wired it incorrectly.

1). Is it normal for the wires in the wall to get warmer when nothing is turned on?
2). Is a light Dimmer even appropriate for controlling ceiling fan speed?
3). Is there any risk of fire with the current setup?
4). What is the proper wiring schematic to add a Ceiling Fan Speed Control where there is already a Wall On/Off switch?

20200224_220034_A.jpg
 
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AlbertHall

Joined Jun 4, 2014
9,281
Is your camera looking at the wires, the wall or the ceiling (can't make head or tail of the picture)?
If something is getting warm then it should be no surprise that it hets cooler with the fan on.
 

MaxHeadRoom

Joined Jul 18, 2013
20,000
Incidentally, I have had a couple of these 'Dimmer' controls where the ON/OFF switch on the pot stays on after some usage, or gets really 'iffy' as to whether it turns off or not.
Max.
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
465
Incidentally, I have had a couple of these 'Dimmer' controls where the ON/OFF switch on the pot stays on after some usage, or gets really 'iffy' as to whether it turns off or not.
Max.
Thanks Max.
I would have thought the wires would get warmer when the ceiling fan is ON instead of when it's off.
I was just playing around with the thermal camera when I noticed these wires. The heat signature of the warm wires can be seen running all the way up the wall (behind the sheetrock) to the ceiling.

Seems to me wires should not be warm (or hot) when they are not providing current to a load. But I'm no electrician.
 

MaxHeadRoom

Joined Jul 18, 2013
20,000
But there is a circuit activated for the Triac dimmer in the switch plate, this is why it is preferable to use the ones with the OFF at zero that operate as a normal switch and remove all power to the 'Dimmer'.
Max..
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
465
Here, h
Is your camera looking at the wires, the wall or the ceiling (can't make head or tail of the picture)?
If something is getting warm then it should be no surprise that it hets cooler with the fan on.
How's this?
Same picture with a digital image overlay (seek fusion)
I suppose if I get closer and take my time I could get an even better defined image. But hopefully this gets the point across.
This is with the ceiling fan OFF. The wires cool down when the fan is on, but I doubt the air from the fan is causing it.
20200225_115627_A.jpg
 
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Thread Starter

Lumenosity

Joined Mar 1, 2017
465
But there is a circuit activated for the Triac dimmer in the switch plate, this is why it is preferable to use the ones with the OFF at zero that operate as a normal switch and remove all power to the 'Dimmer'.
Max..
Ah!
Thanks. Now I get it. I'm a slow learner, but you're a patient teacher.
I'll look for one when I go back to Lowes.:)
 
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