Interesting voltage spike and plateau

I noticed an interesting jump in voltage while looking at the power quality for my home. It looks like it spiked and held at 125V for a few hours, then settled back into a normal range. I didn’t notice any issues while it occurred. This is the first time I’ve seen anything odd with my graph, although I don’t think I can see a full historical view.

Has anyone seen

before? Not sure if I should keep an eye on it or if this is something to expect if equipment is being replaced somewhere down the line.

Hi @whee. I’ll let others with more expertise of what could be happening “down the line” comment here on some potential causes. If you scroll down the Power Quality Sense Labs screen, you can see all of the spikes and dips from the last 30 days.

My initial thoughts after seeing your graph:

  • A majority of the spike is still within the normal range (the shaded gradient in the graph)
  • The behavior isn’t consistently happening (you mention this being the first odd occurrence)
  • There are no other observable issues occurring (i.e. flickering lights)

Probably a tap change at the substation or a voltage regulator down the line. Not something I’d worry about. Utilities use voltage correction devices in various places to keep voltages within reasonable parameters, and most of these devices are not continuously variable, so you end up with these steps at various times of day.

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The rise in voltage most likely occurred at the local power company substation. They might have been working on the line, paralleling two circuits and turned off the voltage regulator at the substation.

I had one a few nights ago too .