^^ Or we could hold a seance and ask the spirits.

This is getting nutty... Put a dang amp clamp on those wires and find out with real numbers exactly what's going on.

We don't need spirits, we don't need clamps...we already have the answer, and toxcrusadr confirmed it...

That floor would light up like a UFO landing pad if it was heated.

THEY ARE COMING!!!!!!

Wow! You reduced your usage by 2/3! :)

At this point, I'd open the panel and have a look inside. There should only be one wire (or a pair of wires for 240V circuits) connected to the breaker. But this wire is going to go somewhere. And if you are luck, you can see where it goes. There also should be a matching white wire from the neutral bar.

At some point, the wires probably go into a junction box. And when you see the junction box, you can see if the wire splits into two branches or stays the same.

For finished spaces, this is hard to trace. But garages are frequently unfinished, so you can often follow wires. Even if the wires are in conduit, you should be able to make an educated guess, as this wire is likely thicker than normal 14 AWG gauge wires used for lighting circuits.

A multimeter would also help. If you have identified a wire that you suspect might be the one that you are tracing, check if it has power. Then flip the breaker and see if it turned off. If it did, then you know you are following the correct wire; otherwise you try again.

A non-contact voltage detector should in principle work as well. But in practice I find they are frequently unreliable and send you on a wild goose chase. A clamp-on amp meter would work, as long as the heater is powered on (i.e. as long as electricity flows). But you have to make sure you put your clamp around an individual wire. If you put it around a bunch of wires (e.g. as part of a Romex cable), then it should always read zero no matter whether current flows.

The cable going to the heater shown on your pictures is 10-3, which is rated at 30 amps, and it matches the 30 amp breaker you pictured. Since permanently installed fixtures shouldn't pull more than 80% of circuit capacity, and thinking nobody would install 10-3 if smaller cable will suffice, I would be tempted to estimate the capacity of the heater around 5760 watts at maximum setting. My humble guess is that the heater is the only thing on that circuit.

Since it has a low and high setting, it probably has two elements, and perhaps only the smaller element is energized all the time, which is why you didn't feel the heat from the heater?

It just being the heater does seem more likely.

But if it's only using the smaller element, it's hard to explain where all that electricity has been going. I still want to hear what an electrician says.

My guess is that the heater has a heating element short. I'm thinking the unit is designed to only shut off one side of the 2 power legs. If everything is working correctly this is fine, but what I've seen happen if the element shorts part way through the circuit it will draw constant power but not enough amps to pop the breaker because of the load the element creates.

Obviously you can't see what's happening inside the wall, but if you shut off the breaker and remove the cover where the wire comes out of the wall to the heater, you can see whether this is the end of the run or whether there are two cables in there, one coming in and one going out to somewhere else. I agree with the above, it seems this heater should be the only thing on the circuit, but that would be further evidence. And you can't assume whoever did the work followed all the rules or even knew what they were. "I can overload this circuit as long as I don't turn on both things at once, it'll be OK."

Jakvis's idea makes some sense. Still, though, there should be 5000 or so watts worth of heat rising from that heater. You'd think the OP would have noticed that.

Yup....

I don't think the heat would be noticable to the OP because the unit is mounted high and the OP would have to stand on a ladder or chair to notice any heat output. Especially if the element was only 2/3's shorted.

Well, it would be pretty easy to test that theory by turning on the breaker, standing on a ladder after a few minutes have passed, and seeing if there is any noticeable heat. I'm still of the opinion that that amount of heat is going to be quite noticeable in its effect on the ambient room temperature. Even if the heater is malfunctioning, and heat is still being produced, a watt is still a watt.

Following

If the short to ground were 2/3 of a 240 volt element, let's see how much power that would waste. Say the heater is 5000 watts. That means the element is about 11.5 ohms, so if it went to ground 2/3 of the way that would be about 8 ohms. P = E^2 / R = 120^2 / 8 = 1800 watts.

I calculated above that the excess load is probably something over 4000 watts. So we're a little short of that in this scenario.

However, a short to ground involving about 1/3 of the element would chew up twice that, 3600 watts. Now THAT I'd believe -- except that it STILL would be making lots of heat.

It's a fascinating riddle, that's for sure!

I have read most of this conversation and I keep wondering if her old refrigerator is in that garage... on that same circuit??

I still vote that circuit was powering the heater inside the neighbors grow operation!

How would the power company know that it was your water heater using all that power? They just know the total registered by the meter. I speculate that they were speculating.

Don't know details in this case, but in some places, electric companies commonly rent water heaters, so they might have lots of info and experience with this..

Any resolution?

I waiting also to hear the outcome from actually measuring with amp meter. No more conjecture.

Apparently the original poster just wanted to save money on the electric bill, and wasn't ready for the pressure of becoming an internet phenom.

Sigh, I keep checking in to see if there's been any resolution. Maybe the Breaking Bad neighbors or the alien power grid felt they were about to be unmasked . . .

Come back, M Br! Inquiring minds want to know!

(Am I correct in that the offending ceiling mounted heater had a simple black knob to turn it Up or Down, but not Off? This thought occurred to me in the middle of the night when I was running through my usual list of daily trials and frustrations . . . . )

This has been one of the most interesting threads for a long time. It's too bad the OP did not come back to give us the final outcome.

Thanks for the update MRB04 - these posts have been like an old fashioned radio serial - Tune in Next Week for More Adventures of -------

Fascinating thread! Can’t wait to find out what happens...

Glad to hear you'll be back , hopefully with the mystery solved. I agree Maire_cate, it is like a serial!

I’d still love to hear more details!

Can't believe I read this far and there's still not a final answer! Come back and let us know, MRBr04!

Any solution?

Your electric company will probably come out and do a free energy check - I'd start there.

Following

MRBr04

Any update?

Try to reduce the timne your AC is on and change all the bulbs in your house with led or eco ones.

Sounds like you only read the title...

This is a two year old post.. I was just thinking about it recently and wondered what the original poster had discovered. I wish people would come back and share their outcome after getting so much help/advice from the people on this site.

I ended up getting solar. We found my bills were so high because of a hot tub and water heaters fir our animals (we are on a farm). We have not had solar for 2 years and our bill is $11 every month. Our usage hasn’t changed.

The OP took our advice and ran, never to be seen again. Kind of rude in my opinion.

Oh, they probably just forgot to come back and give us the promised update. Given the long progression of this thread and the OP's tone in posting, I don't think they blew us off on purpose.

Amazing there are 300+ posts though. :-o