P12 showing voltage in at under the voltage out…

I’m not sure why yet, but all of a sudden my voltage in shows under 120, when it’s always been over 120. Oddly, the cable and outlet are the same. I only changed an outlet faceplate, and the location. Cause for concern? Give it a few days?

I would give it day or two. It is likely just a coincidence.

If it remains low, switch everything back just to be sure everything is OK.

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Thanks, Elk. It has dropped below before but it is just for a quick bit of time. Seeing it over hours and hours now, and can’t seem to wrap my head around it yet.

My power has always fluctuated so this does not bother me.

Let us know what your power is doing in a day or two.


Upgrading a faceplate seemed like a good idea, but this data says otherwise. I decided not to use the 20A receptacle that was supposed to go with it, because I don’t yet have a 20A circuit in place. Used that Maestro/ATL Power stuff that I’ve had for a long time. Guess it’s time to rollback the change!


It will be interesting to learn if the voltage goes back up.

I removed the faceplate and have still experienced lower voltage. Is it true that the output is 120v when the input is less? How could that be?

As I suspected, it is only a coincidence the lower voltage and the new face plate happened at the same time.

The voltage output of a Power Plant can be higher than its input. One of its job is to regulate voltage.

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It is still noticeably lower voltage after weeks. Maybe I damaged/lessened the efficiency in the circuit during my exploration. I have no idea why it’s dramatically different. Really itching to bite the bullet and DIY a nice dedicated 20A. Wonder how that would change things?

Are you relying solely on the P12 to tell you the voltage in and out? If so, I suggest checking the voltage with a multimeter. I doubt anything is amiss.


Likely nothing to do with the P12, and just a change in your local distribution. Typically I am 125ish, but I am sometimes down around 118. Depending where you are, can be a seasonal factor too, i.e. if there are lots of high current loads on the line, like AC or heating. —

I’m was never inclined to believe that it was the P12, but rather another change I describe. It happened suddenly, as I describe.

I just stopped worrying about it, yet want to believe that the P12 is reporting accurately about whatever it does report.

Hey @Elk , you really need to be reviewing who in your “community” is flagging posts. Obviously some “children” have intentionally flagged everything I posted. There is nothing in my post that warrants being flagged. People who do this “false flagging” need to be slapped.

You will note your post remains, unedited as well.