Panasonic Whispergreen Fan/Light and Signal Wire

[Rossn]

I'm replacing a few bath fans with the Panasonic Whisper Greens, and am short one wire on the signaling side to use all the desired functions.

From the original fan, I have a 14/3 running from two line level switches an unswitched 14/2 was added when the roof was off.

What is ultimately needed beyond the constant power is a switched line load, and a switched signal load, which would require a total of 4 conductors to the switch box.

Since I have another ground at the fan, I do not know if I could use the ground wire as one of the signaling wires. I read in one forum that the signal wire is on the neutral side of the circuit, and therefore if any of the signaling circuit grounds out, then it would likely trip an AFCI on the ground fault side of things. That then made me wonder if it would be possible to safely use the neutral for both neutral and one leg of the signaling.

Does anyone know specifically about this?

There is the potential to have the unswitched power supply on the same circuit as the existing switches, and then pull the neutral for the switched line load off the constant power, though it is not preferred due to the current not running through a cabled pair of wires, which would generate much higher EMF.

 

[Fitter30]

1. Have you tried just tying the signal wires together and just switching power

 

[Sponsor]

 

[Stuff]

Assume you currently have fan and light but now have night light you want to control. Or do you want to use the red signalling wires for high/low speed control? If for speed then you are stuck as you need both wires to a switch.

First of all any neutral needs to be on the same circuit as the hot, you can't use a neutral from another circuit.
Second you can't use a ground wire for signalling.
If the neutral is from the same circuit you need to have NM wiring and plastic boxes. At the fan need to have both cables come through the same knock-out. This is to avoid EMF heating. Also if there is a GFCI then everything needs to be tapped either upstream or downstream of the GFCI.

 

[wwhitney]

You haven't specified how many signaling circuits you need from the fan to the bathroom box.

If it's just two, and the issue is that those two signaling circuits don't share a common wire, this is easily resolved with a relay. E.g. Relay-In-A-Box RIBU2C. That's two separate relays in one small enclosure. You can power the two coils with the two switched hots from your 14/3, and you get two separate pairs of contacts.

If the issue is that you need 3 signaling circuits (and then I infer from the OP that they do share a common wire), then you're out of luck and need to run additional wire from your switching location to your fan. Or look into a wireless solution that will provide the proper number of channels, since you have constant power at both the fan and the switch location.

Cheers, Wayne