Power Quality - A high Number of of Voltage Dips or Spikes

How was your issue detected?:
I noticed the situation in Sense Labs

Did you noticed any other signs of this issue around your home?:

Screenshots from Sense Lab

I downloaded the CSV data and noticed that a dip threshold appears to be <110v, not the -10% (108v) suggested in the text. At 110v threshold I have 74 hits, at 108v I have 13 hits.

Where should this threshold really be to ignore the dips from starting motor loads?

I have a ground source heat pump that seems to be the major culprit. I have had it tested recently and it is performing within spec.


A lot depends on how sensitive other equipment in your home is to magnitude and duration of voltage dips and swells.

I think this Power Quality measurement also gives you an idea of how well regulated your power really is.

@RyanAtSense, @JustinAtSense,
Since there is a a standard IT Industry Tolerance Curves for power quality events, it might be worthwhile characterizing sags and swells vs that standard, though the standard is really for industrial usage.

It turns out we had a dicey neutral.


Great catch and that’s exactly the type of post-assessment (Power Analysis) data that Sense could likely use to go deeper — one might hope for future refinements and alerts: “You may have a dicey neutral”.
@JustinAtSense this seems like a good one to request data access on.


We’re already on it, @ixu :slight_smile: