I am experiencing an oddity in the voltage reading of my Blue mmWave Dimmer. I have both a mmWave Dimmer and On/Off switch connected to the same power lead via pigtails in my bathroom, and when the light is off my Dimmer is reading around 67v, but 120+v when the light is on. My On/Off switch doesn’t seem to have this issue regardless of its output, and reads slightly higher with a 1.5-2v delta vs the “on” reading of the mmWave Dimmer.
The differences between the switches isn’t an issue, but the variance of the voltage between the “on” and “off” states of the dimmer has me puzzled. I would compare to my other standard 2-1 Dimmers, but those don’t seem to have a voltage reading to view.
Is this normal? weird? something horribly wrong and my house is going to explode (/s)?
This is mainly my curiosity, but want to make sure this isn’t a sign of some issue with the mmWave dimmer I just purchased.
Unless you are wired improperly . . . Dimmers leak voltage, relay based switches don’t. That’s why the UL requires air gaps for dimmers. If you pull the airgap and you’re still getting voltage on the load, that’s different.
Also, unless you’re using a low-impedance meter, you may be measuring ghost/phantom voltage.
I haven’t bothered to measure the load side on any of my dimmers with an actual meter, I am only basing this off of the information I am viewing through HA being reported by the switch… I would have compared it to the other Blue dimmers I have, but they don’t report voltage.
Anyway, if this is normal, then great! Question answered. As I stated, it was mainly for my curiosity, as on its surface it seems a little weird… I just figured it would constantly be reading 120v on the Line side like the On/Off switch does. The On/Off switch doesn’t read 0v when it is turned off, so I didn’t expect the dimmer to report a change in voltage when turned off.
Regardless, I’m confident in the hookup and everything as I am an electrician, but I’ve never had the opportunity or need to measure the voltage on the load side of a dimmer… I either wire it up and it works, or if it doesn’t work it gets replaced. It’s a troubleshooting step I’ve never had to bother to take.
I’m pretty sure there was some discussion around the lack of accuracy in the load measurement of voltage of dimmers during the beta testing. Inovelli chose to expose it anyways, but I wouldn’t worry about it.
