“Power Quality - 57 times: More than most Sense users

How was your issue detected?:
By watching the lab part of web interface

Did you noticed any other signs of this issue around your home?:
When we moved in 4 years ago, as soon as we turn on eg 1200 watt convection oven in the kitchen, some of the lights in the house (mainly bathroom) starts to flicker.

Screenshots from Sense Lab

  • Sense Labs graph screenshots

  • Sense Labs notification Screenshots
    not available

I see almost 10 volt difference between the split phases.
I have solar, connected at 240 volt.
As is the AC, my stove, electric dryer and EVSE
No heavy load on only one of the legs of the split phase.

I suspect you’ve got a loose neutral connection in your panel(s). Probably a loose main neutral lug, but check the individual circuit neutrals as well and let us know. Good luck!

I forgot to mention a few things.
When I got here the house still had the original Zinsco service panel 100 amps from when it was built in the 50’s.
I replaced the main service panel with a new 200amp when I installed solar 2 years ago and added new grounding rods according to NEC code.
There are 2 sub panels that are still original. The lights that flicker are on one of them , it is in a closet and I never looked at it closely.
Moving the convection oven outside, plugged into the second sub panel makes the lights flicker in the bathroom. Is it possible that the neutral in one of the sub panels is not tight ?
Is it even possible that the neutral is not tight at the transformer that I share with 4 other homes ?

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Yes, the neutral could have a bad connection:

  • in your panel
  • in your meter base
  • at your mast (overhead service)
  • at the transformer
  • at any connection/splice in the conductor between your panel and the source (transformer)
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I have been watching my ‘Voltage readings’ for several weeks using the ‘Power Quality’ graph in the new ‘SENSE Labs’ section. My graph is not as bad as some others who have posted, but it got me to thinking. Do I have a good connection at my external house ground rod?

I shutdown all the power to my house.
I removed the ‘acorn-style grounding clamp’ and inspected.
What I found was a lot of corrosion. I think my clamp was probably providing a good connection (I didn’t run any tests), but went ahead and cleaned the wire and the ground rod with a wire brush and emery cloth and installed a shiny new $2.28 clamp from Lowes.

I will keep watching the graphs to see if that maintenance check helped. Even if if doesn’t help, I have peace-of-mind knowing that my grounding bond is good.

This was an easy item to check and to service.


Hey @dannyterhaar. We had Data Science take a look at the data here and they noticed indications of very weak floating neutral-esque events, all in the 1-2 volt range. Nothing very dramatic, but appears to be possible.

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Thanks for the feedback!
So that would not explain the 8-10 volts difference I sometimes see in the lab reports.
Will keep this in mind as I do more research.

When I moved into this house 4 years ago, I wanted solar and pulled permit and upgraded the zinsco 100 amp panel from 195? to a modern 200amp.
The zinsco already had scorch marks at the busbar from charging my EV at 40 amps (50 amp breaker)
Disaster waiting to happen

photo album at [https://photos.app.goo.gl/aJra9HiNzkVMgZF57](http://photo album )
My overhead powerlines come together with my neighbors on the top of a pole and from their another 2awg (for 2 homes!!!) across the street [photo1]
To the main split phase distribution line [photo2]
My house and 4 others are connected to one 25KVA power pole transformer. [photo3]
I heard that they are capable of double the capacity at the cost of high oil temperature.
That included a new meter base & new weather head / mast. [photo 4]
The utility company connected my 2/0 awg cable to their 2awg with heavy duty clamps [also photo4]
The main service panel is new and upgraded from 100 amp -> 200 amp [photo 5]
[photo6&7] new grounding rods, connected to the 195? setup tied to both gas & water line & rebar in concrete
[photo8] sub-panel in garage , is on my to do list to get larger supply wires (prob 2 awg instead of #6 now)
[photo9] sub-panel in closet in the house. have not opened it up yet but kind of expect this to be 195? as well and probably one of the more probable causes of the problem. Our kitchen counter has all outlets on 1 breaker, and also the lights (that flicker) in the bathroom are on it.
It is a mess, but it was what I could afford :wink: