Power Quality - 1000x last 30 days, but is it an *actual* power issue? or a CT/WiFi connection issue? or even something else?

Hi folks!

Would love to hear any thoughts on what I’ve been experiencing. As a new user, I’ve shared some links to Google Photos instead to be able to share more content.

How was your power issue detected?

So… a bit of background:

A year ago, in April 2023, our new-build home (1500 sq.ft. townhouse) was completed. We moved in May 2023.

Within the first few days, we noticed a few odd electrical-related things:

  • lights were occasionally flickering
  • dryer breaker kept tripping (turns out the receptacle was installed poorly and it was arcing)
  • when we had some TP-Link Kasa smart switches installed, we discovered that the electricians put in dead-end three-way circuits, which I’m pretty sure isn’t to Code (In British Columbia, at the time of construction, adopted code was Canadian Electrical Code, Part I, 25th Edition, Safety Standard for Electrical Installations, Canadian Standards Association Standard C22.1-21)

Then in June 2023, we suddenly noticed significant electrical issues (excuse the messy home in the videos attached):

We ended up having the main electrical line serving our townhouse (from a shared meter room) cut and half of it replaced, with new conduit run around the building as the original cable was buried in slab at grade - with a new junction box added to the back of an inadequately protected accessible parking sign post to connect the new half of the cable with the old half from the meter room (…you really can’t make this stuff up).

The more significant symptoms went away, but I still had odd issues pop up:

  • our UPSes would occasionally click on and off
  • LED lights would still flicker, albeit rarely
  • our living room TV would occasionally glitch (power cycling by itself, display errors that needed to be corrected with factory reset, etc.)
  • mobility scooter battery failed without explanation and unable to accept a charge any longer

So I bought a Wiser Energy-branded Sense unit to see if anything might come of it. For the first while, things seemed normal.

Then, later on, I noticed the power quality issues showing up in Sense Labs:

Screenshots from Sense Lab

Here are Sense Labs graph screenshots of each day over the past while

I’ve also aggregated the data downloaded over the past while into a spreadsheet (date and time edited into separate columns rather than the default timestamp as downloaded):
Power Quality Data.xlsx (158.4 KB)

Here’s a screenshot of what the page currently shows:

Where I’m at…

Now, given the history of electrical problems, I definitely am inclined to question crappy electrical work (and likely will push me to ask for a full replacement all the way to the meter room).

But there also are are a few things I noticed in the data which have me questioning whether these are actual power quality issues or an issue with the Sense unit itself:

  • April 19 ~5pm through April 20 ~6am, the voltage graph suddenly looked “normal” with no user intervention
  • April 22 over the early morning, Sense seemed to have suddenly stopped recording data, however it seems that a reboot resolved that issue (but it didn’t do anything to change the dips/spikes observed on the graph after the data came back online)
  • on April 28 (earlier in the day as this post) just after midnight, I installed additional CTs to monitor two dedicated circuits…ever since then the graph this morning has looked “normal” (although the raw data itself has recorded a few events this morning that don’t appear depicted in the graph)

Or maybe it’s a bit of both? Or maybe something else not-yet-diagnosed in the wiring throughout the home? Or maybe an appliance has been malfunctioning? shrugs

Would love to hear everyone’s thoughts!

EDIT 04/29: Corrected hyperlink to the video showing HVAC controller cycling and made some minor edits for clarity.

Hi Hobs, welcome to the forum! Your first post is full of great details. You also seem to have a good handle on the relevant issues. I like how you document everything and are working systematically to diagnose.

I wonder if you have compared notes with your neighbors. The fact that your power quality graph cleared up for 12 hours on its own without you doing anything is significant. Then it went back to lots of spikes, which makes me think the issue might be outside your home.

Thanks Jeff!

Indeed - recently, two other neighbouring units (one adjacent to mine, and another in a separate building across from mine, but all sharing service from the same meter room) over the past two weeks experienced what we saw last June (for them, the tell-tale sign was that their heat pump and hot water heater were malfunctioning). They’ve since had to have their main service lines replaced in the same manner as mine was.

Unfortunately, I’m the only unit that has a Sense…so I don’t have any data points to go off of for what may be seen by other units, but anecdotally it definitely seems like an unresolved issue with having only half the main line replaced.

I have contacted our utility provider, BC Hydro, which has confirmed that everything upstream from the meter room (i.e. their transformer and other components supplying the electricity) appears to be working fine. This leads me to believe that it’s likely something related to the meter room or the lines coming from each meter to each unit.

With all that said, I am definitely a lay-person in this realm and know that correlation isn’t necessarily indicative of causation…so am definitely keen to hear all possibilities!

Generally, you can trust the Power Quality results. But there have been a few occurrences of Power Quality giving erratic spikes. You might want to try a reboot as this user did:

Two other suggestions:

  • You might want to ask your electrician how your townhouse is wired. Single family homes are generally single split-phase, but apartments, condos and clusters of townhomes, especially with adjacent meters, are often wired via a three-phase supply, something that should still work with Sense, but worth knowing as you pursue this potential issue.
  • If a reboot doesn’t change things or if it does, but only does so for a short while, then consider checking in with Sense support. See @JamesDrewAtSense ’s message here:
1 Like

Thanks Kevin! Appreciate the info and tips!

Indeed, the complex is supplied with incoming 800-amp, 120/208-volt, 3-phase, 4-wire service. From the meter room, units are then supplied with 150-amp, 120/208-volt, single phase, 3-wire service.

The reboot (following installation of additional CT clamps monitoring dedicated breakers) seems to have made the graph look great:

But the power quality data still shows some events occurring since the reboot:

date minimum_leg0 maximum_leg0 sustained_minimum_leg0 sustained_maximum_leg0 minimum_leg1 maximum_leg1 sustained_minimum_leg1 sustained_maximum_leg1
2024-04-28T00:07:01.000Z 54.78 121.75 121.44 121.66 98.57 122.14 121.89 122.08
2024-04-28T00:12:03.000Z 100.45 124.23 121.2 121.53 105.08 128.47 121.65 121.81
2024-04-28T00:29:05.000Z 113.72 121.37 121.06 121.24 56.59 121.77 121.58 121.68
2024-04-28T00:35:07.000Z 79.77 122.62 121.2 121.32 64.66 125.98 121.72 121.9
2024-04-28T01:03:01.000Z 119.65 126.36 120.13 120.27 98.14 121.87 121.64 121.8
2024-04-28T01:25:04.000Z 102.13 120.93 120.53 120.84 108.64 123.36 121.6 121.78
2024-04-28T01:58:10.000Z 112.35 120.77 120.51 120.81 55.1 121.51 121.32 121.48
2024-04-28T02:04:02.000Z 62.32 124.16 121 121.22 49.95 122.03 121.81 121.97
2024-04-28T02:54:10.000Z 51.46 122.78 121.31 121.44 68.76 124.08 122 122.31
2024-04-28T03:11:04.000Z 75.86 120.63 120.32 120.55 75.61 122.19 120.82 120.96
2024-04-28T03:33:09.000Z 101.78 121.17 120.82 121.05 120.64 130.03 120.95 121.15
2024-04-28T04:01:01.000Z 52.35 129.27 121.02 121.32 85.63 121.49 121.08 121.3
2024-04-28T04:56:11.000Z 116.06 120.47 120.19 120.37 65.97 121.37 121.1 121.29
2024-04-28T05:02:01.000Z 118.18 120.59 120.4 120.52 59.28 121.69 121.51 121.64
2024-04-28T05:18:04.000Z 120.62 126.82 120.72 121.09 95.2 121.94 121.68 121.85
2024-04-28T05:24:06.000Z 84.1 121.46 121.06 121.35 120.98 127.92 121.57 121.77
2024-04-28T05:30:07.000Z 81.75 121.37 121.14 121.29 120.89 129.41 121.57 121.92
2024-04-28T05:46:10.000Z 103.1 121.93 121.37 121.51 109.18 124.84 121.93 122.21
2024-04-28T05:52:11.000Z 121.71 124.23 121.82 121.97 103.02 122.23 122.1 122.17
2024-04-28T06:14:03.000Z 61.31 124.7 121.74 121.92 51.62 122.38 122.13 122.3
2024-04-28T06:25:07.000Z 116.35 123.25 121.2 121.44 70.22 122.13 121.9 122.08
2024-04-28T06:26:08.000Z 105.6 123.42 121.39 121.5 66.15 128.1 122.04 122.1
2024-04-28T06:31:10.000Z 106.87 121.88 121.69 121.82 122.08 125.65 122.19 122.35
2024-04-28T06:36:13.000Z 122.09 125.32 122.21 122.37 109.89 122.71 122.45 122.6
2024-04-28T06:37:13.000Z 97.37 125.32 121.04 122.43 108.04 126.2 121.33 122.73

I have definitely had an instance where Sense stopped recording data and didn’t resolve itself - needing my intervention to reboot via breaker. Can’t recall if I sent in a service ticket at that time - will double-check and send in a support ticket about that if I haven’t already!

Not surprised that you have 3-phase. That’s probably a good thing to tell support when you work with them. Seems like you still have something going on. I have a little charting program that looks at which quadrants the over / underage occur in. You can see yours so far on the upper right, compared to other users. Looks like your issue “signature” is primarily a L0 dips across all L1 conditions (over, under and in-range).

Hi, @hobs. I enjoyed reading your post—for the information and thought you gave—but I am sorry for the trouble you may be having in your house.

So, the image you posted, which I included below, looks very much like an issue we sometimes have: power quality in Sense records erratically and then may stop recording entirely. A “reboot” should do nothing to influence if you have bad power quality in your home, so for anything before that date—especially with the big spikes—I would be skeptical of any data you see.

I would mention, though, for users who see issues like this, "Did you find your lights flickering? Did you find your other devices failing to run well or acting erratic… and as you posted here, it appears you did as well. So you may be having both of these issues.

The first step, as you did, was to reset your Sense monitor. This is actually one of the issues we discussed in the blog post @kevin1 just wrote about the signals page. If you checked before the reset, you might have seen a deviance from 60 Hz in the frequency section—also, maybe not.

If you have not, I advise you to file a support ticket so we can look into how to help you. If you need my help, feel free to send me a private message.

Going from a 3-phase setup to a single phase - as @kevin1 said, is important to mention as Sense is generally equipped to handle a split-phase home rather than either of the other configurations mentioned, so there may need to be a few things that we would need to check on our end specifically.


Thanks @kevin1 and @JamesDrewAtSense! I’ve just sent in a new support ticket to see if there’s something more that could be dug into with all of this.

@kevin1 - Looking at this and a few other threads I’ve stumbled across, I’m super appreciative of the background knowledge you bring to Sense Community and share in a digestible manner, and especially for introducing different ways of interpreting and visualizing some of the data!


Thanks @hobs - the way I see it, our homes really want to tell us all about what’s going on in them and where things are broken or could be better. We just need to have the right data and “listening tools” (visualization) in place.

ps: Battling broken sprinkler lines using Rachio and Flume this week.

@kevin1 - Haha… fun times! Bring on the spring/summer projects :rofl: I’m now simultaneously halfway-down an energy efficiency rabbit hole. Being the keener that I am, silly me decided to splurge on an independent energy assessment to gather more info… Surprise! Ridiculous numbers like 8.18 air changes per hour on a blower door test at 50 pascals, and definitely lots to question about the windows and insulation. (Can’t say I’m too shocked given the other issues we’ve had with stuff like electrical… but still kind of ridiculous given that this was completed in 2023 to requirements based on 2018 BC Building Code with some supposed additional layers municipally-mandated energy requirements/considerations.)

OVERALL UPDATE: Lucked out with my support ticket ending up back with @JamesDrewAtSense who kindly did an even deeper dive and took a second look at everything, including making sure that the Sense installation itself looked a-okay. Despite glitches attributable to the known experimental-ness, the underlying info still appears to be indicative of a possible floating neutral, so definitely taking the advice to get someone in to (hopefully) diagnose and repair!