Need help identifying culprit of 750w vampire or phantom draw

Hi all! I spent some time today reading through other great threads and used the circuit-by-circuit method to find the culprit of an AO of 800-1000w. I turn this circuit in question off and find that my AO goes down to ~350. So we’re talking ~750 watts!

So here’s the deal. I’ve traced this circuit to every end point I can think of and cannot for the life of me figure out what could be drawing that much power! I’ve unplugged everything and still the circuit immediately goes up to and stays at an 750w give or take of increased usage.

I am the second owner of this mountain home. We have a well but the pump is fed from a sub panel directly below the main coming from the electric company and thus not read by Sense. The house was built in 1964 and had an old doorbell and intercom system that are no longer active. The circuit in question does not trip AND anything plugged into it when it is on works well. So I’m stumped. Seems like there is Something using the power but for the life of me I can’t think of what it could be.

One last note: I have seen outdoor outlets in the front landscaping of the house but have measured with a multimeter and they are dead. Have not traced them back to panel yet.

When that circuit in question is on, the usage seems fairly consistent. That is, the draw begins and stays roughly at a similar level though there are times when it fluctuates.

Last last thought: I have the Sense device itself borrowing from a non-empty circuit. Could this be an issue?

Thanks for any thoughts or help!

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@tjcook,
Wow, that’s a big single circuit source for an Always On. Just to confirm - when you say you are using the circuit-by-circuit approach, you are flicking off that breaker when the house is relatively quiet, and the Power Meter drops by 750W, right ? I ask, because the Always On bubble won’t respond to a change like that for a substantial period of time. If so, two thoughts:

  1. It’s not the Sense monitor borrowing power - the monitor only uses 2-3 Watts.
  2. The giveaway should be what doesn’t work when you turn that breaker off ? But it might be trickier than you think - it took a while for a couple of community folks to find mystery heaters, that they didn’t know existed.

One additional way to get ideas - try the community device library and set the tags for the approximate wattage of the mystery device. You might get a hit:

https://community.sense.com/tags/c/device-detection/device-library/25/701w-800w

I once was asked to try and track a high electric bill at someones house.
Turned out there was a huge fan in the attic that was on 24/7 on and used a lot of energy.
I solved that issue with a 3 way switch (on/off/auto) where the auto position had a thermostat set to go on at 100F in the summer when it got really hot there.
Helped a lot in that case.

Thanks for this quick and great response! I was mis-speaking regarding AO—I should have been referring to the Meter showing live usage. Here is a pic:

I did look at some lists of appliances and common current draw from them. It does seem that if it is something I don’t know about, it’s likely a heater or similar utility appliance. But because this is a single circuit I have exhausted every possible thing I know to be on that circuit. I’ll keep noodling and sleuthing.

How exactly does your service enter & where are your CT’s connected?
I am confused when you say “sub panel directly below the main coming from the electric company”.
To be a “sub panel” it has to be powered from a main panel. You could have 2 main panels with a common fused disconnect. If that’s the case and your CT’s are located in one of the 2 main panels and not the disconnect then that makes sense and your Sense would be missing out on everything powered by the other panel.
If it is a sub panel and your CT’s are located on the main panel it’s fed from, then your Sense would be reading everything powered by that sub panel.

With that being said, what else is on the circuit in question? What area(s) does that circuit power?
Is it possible to leave that circuit off for some time until you discover what no longer works? Double checking nothing critical is on that circuit like a fridge/freezer.

You don’t happen to have gutter heater tape to prevent ice jams do you?

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