Seeing Big Difference Between Sense and Meter After First Month - What could be causing?

So the only thing running through that second bundle is a ground wire ? Big sheath for something so small. That looks like your earth ground connection via the copper water pipe. The code requires a conductive pipe or rod that goes down 8 feet into the ground.

The green ground wire being connected to your water pipe is a typical grounding method. The amount of copper and buried metal pipe in a wet environment (read: conductive) is usually the best available interface “to the Earth”. The NEC (National Electric Code) allows for the ground wire to be bonded to a water pipe as long as there’s something like 10ft of buried pipe. The problem with using water pipe rather than a purpose-installed ground rod is that city water pipe these days can potentially have insulators to deliberately prevent conductivity and electrolysis that corrodes metal pipes. I think it’s probably rare though that grounding to water pipe is insufficient. It can really depend on soil types and moisture content. Take this info with a grain of salt though, a licensed electrician should have installed, verified/tested your grounding at some point.

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Yeah, that’s all that comes out of it. I’m thinking it’s a current leak somewhere else, maybe the insulator is worn but not completely gone that it would short circuit. Instead I’m probably losing (270w = ~2amps @ 120v?) assuming my 200 kWh/month is being used up continuously. Can Sense pick up leaking current under that “Other” group? If so, at least it would isolate the problem to either my circuit breaker or the wires running to it.
Booking time with my electrician.

To take this a step further. If you have a main breaker in your panel, turn it off. If you don’t (and in theory you won’t because your main is in the panel in the basement), turn off all the breakers on the panel where your Sense is installed including your Sense. Go outside and look at your meter. Is the horizontal disk spinning? If yes, power is being used elsewhere. If no, time to revisit your Sense installation. Check that the CT’s are actually on the correct cables and fully closed etc…

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“Actual” means actual reading of the meter. Check last months bill, I’d guess it was estimated. A low estimate last month would cause a high actual this month.

We have NYSEG here, bills are estimated about every other month. Billing cycles run from 23-32 days with no consistency whatsoever. Have no way of knowing when they will actually read the meter.

Your best option will be to read the meter manually and compare it to billing cycle you set in Sense.

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Yes. However there must be a jumper across the meter (or across any threaded connection) to the side that passes through the wall. I noticed it appears you do not have one. A simple inexpensive fix. I believe the reasoning is if the meter ever needed to be replaced the person replacing it would become the jumper and electrocuted. Also if the threads ever became loose not only would you have a flood you are more likely to be electrocuted.

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Ah I never would’ve have thought of that, if the previous month’s was estimated. But I just checked, and it’s actual too, so I guess they don’t estimate here. And the readings do line up with what the meter says right now.
When the electrician finally comes, my first suspicion will be the wires running from the junction that our sump pump is connected to. they go to both by circuit breaker and the neighbors. And yet, there’s no recording of it on Sense. I wonder if they somehow wired it in upstream of the breakers main lines.
It seems like a stretch for my sump pump to use 200 KwH a month, since it only comes on after it rains, for a few seconds every several minutes. But maybe it got wired somehow into the neighbor’s circuit somehow, and it’s drawing almost 2 amps constantly at 120v, if my uninformed rough calculation is right.
Or you tell me if that sounds very unlikely, even in a scenario where our wires somehow got connected together.

From all your info thus far, yes it does seem unlikely the sump is using 200kWh/month.

I lean more toward the following possibilities:

  • Sense CTs not being ideally clamped around the wires. Check to see they are fully closed and that they aren’t pressing against the wires/panel when you close the panel up.

  • Your building services (outdoor lights?) and/or a neighbor’s circuit is feeding from your meter. Hard to tell how that might be wired. Where is the sump power feed and breaker for example? We seem to have determined that the ground is running to the sump pipe but where is the sump power? That is normally not wired to tenant’s meter though with only 2 meters evident it stands to reason that it’s powered by one of those metered feeds.

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I’m having the same results but on further investigation there seems to be something I don not see in the app. The usage summary and the activity monitor in the app do not seem to correlate. For instance, I see the 6000w activity of my dryer over time in the activity but in my daily usage report none of that large usage is calculated. Same for my EV charger. The devices are identified but I cannot seem to find any way to edit the Usage report. I’ve logged into my utility account and seen the daily usage and visually it appears close to the activity monitor, but its very different from my summary report.

Right, because our house is only two units, the sump pump has no other source of power. I traced the wires from our sump pumps outlet to a junction that then splits off wires going to both my breaker and the neighbors. But again, I don’t see any trace of the sump pumps activity in my sense, and that’s the only one missing, so I wondering if there was something funny about how it got wired into my wiring, possibly before the circuit breaker.

Oh interesting, I would not have thought to manually compare the totals. Maybe it’s still sometimes showing up under “other”? With mine, even for the devices it’s recognized, specifically my HVAC fan, sometimes it still shows up under Other when it turns on. Other times it’s correctly identified under it.

Sump pumps are usually not particularly high power and yours is probably modest. You need to look in the main Power Meter (PM) view when the sump pump activates (or doesn’t).
Pick a quiet/stable period in your electrical usage and confirm constant-ish usage in the PM. While viewing the PM, pour a bucket of water in the sump to make it activate and check for a spike in the PM.

How often does that sump pump kick on? the green wire is normal for some areas to “bond” to the water pipes… the real ground rod is actually outside, bottom conduit from the two meters, probably runs down to a ground rod, two light grey feeder cables run from meter box to inside main breakers. These cables are probably 2 or 3 conductor grounded, and carry that ground from the meter base into the main breaker panel. I’m going to assume natural and ground are bonded in the double meter panel. so these additional grounds indoors are technically ok, though it all should be done in one place. I bet its the sump pump, yours looks full right now, and depending on areas, sump pumps can run quite often just to keep water out of the basement. Most people are used to sump pumps only running when water is high, or during rains, etc… Whos panel runs the pump, the basement lights, the outside lights, do you have one furnace or two? who pays for that? Its worth digging in to see which one of you are paying for the “common areas”. it cant be both of you…

Are you saying each panel has a sump
Pump or saying you have 1 pump that is wired to both panels?

It’s 1 pump, but the wires run to both of our circuit breakers. It’s probably the same one powering basement lights. We have no outdoor lights. We each have a furnace, I can see that activity on the Sense. But no, the pump does not register on the activity in Sense when it turns on. For us, it also only. turns on after it rains for a day or two. Ours is a 3/4 hp pump, so it only comes on for ~5-10 seconds at a time roughly every ~3-5 mins when it does rain.

If both panels are connected to 1 circuit after the meters then current can be fed from either panel to power the other panel. Assuming that the pump and basement lights are 120v. Then L1 in panel 83 might me hooked to L1 of panel 85… so “power” would be-able to go from L1 bus bar to L1 bus bar. Even flipping off the main for 83… one bus bar would be hot on 83 because the circuit would backfeed from 85 … powering L1’s bus bar.

If this is the case… that needs unhooked. This method wouldn’t share electric cost for what lights and pump. It would be interconnecting one leg of 2 services.

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Mystery solved! The electrician tested shutting off the breakers, and the meter didn’t stop…but the other one did. Turns out, Occam’s razor on this one, the electrical company simply mixed up which meter got associated to which account. So all this time, I’ve been paying the other unit’s electrical usage, and the other unit was paying mine.
Electrical company came by, verified this was the case, and is now working to fix the issue and all the billing differences. Thanks Sense!

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Congratulations for solving ! That’s always the first thing to investigate in big discrepancy situations, because the utility revenue grade meters are seldom “wrong” - they’re just misunderstood.

Please share the correlation results between utility and Sense once you get it fixed. I would like to add your story to this summary.

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I bet your neighbors aren’t going to be nearly as excited as you are…

Luckily we both only moved in a year ago, so it’s not like there’s decades of bills for the utility to go back and fix. But what’s several hundred dollars among friends…? :slightly_smiling_face:

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