Aeon Home Energy Meter - where to clamp for individual circuits?

I just received a 3 pack of the aeon home energy meters to start monitoring some individual circuits (e.g. furnace blower, central AC, … dishwasher maybe?), and am a little confused where to put the clamps.

I saw there was a thread about using each clamp to measure separate circuits, so 2 clamps could measure 2 different circuits. I put one clamp over the hot going to the 20a breaker for the furnace, and was going to put the other one on the AC, but it looks like that one is a double 40a breaker.

Do I squeeze one clamp around both wires going to the double 40a breaker? Or do I need to use 2 clamps for that?

The clamp must only go around 1 wire (the hot or the neutral).

If you clamp it around both, the alternating current going in opposite directions cancels out the induction field and it will always read zero.

In this instance, it would be 2 hots going to two breakers, like this kind:


Here’s a real picture of the breaker in question:


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Ooops… yah I thought of that the second after I posted.

If this is a 240v (i.e,. multiple phase) circuit, then I don’t think the HEM will accurately measure it; but I may be wrong. Maybe the multiple phases will “correctly” be measured as double current if one clamp is put around both wires concurrently.

If that doesn’t work, you may need to put a clamp around each individually and manually add up the current usage values reported?

Or wait until a real electrical expert answers this :blush:.

Yeah, mabye I’ll just start with one clamp on the furnace and one clamp on the dishwasher. After all, it’s going to be a while before the AC sees any use again!:snowman:

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Do you guys use an electrician to install these or do it on your own?

I have done it on my own, but I never feel relaxed while doing it!

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I have never removed the circuit breaker panel cover hence kind of hesitant to use these Aeon energy devices.

Good caution, can kill you.

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One clamp around 2 cables will read 0 if they’re opposite phases (2x 120V) because the induction in each cable cancels the other out.

You can just use a single leg and modify your api to double the amps on that meter. For any 240V load without a neutral, both wires will have identical current draw.

Please be careful in an electrical panel. Best practice is to turn off the main breaker before touching anything. Have a flashlight ready.

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However, the main breaker will not kill power to the legs before the main breaker. If you’re working on breakers behind the main breaker then you should be good. But often folks are putting these devices in as a whole home monitor and thus the clamps go around those always-hot legs coming in from outside. Either way, with the panel cover off those always-hot legs are exposed. One false move and you better have a strong heart.

If you’re looking to have a monitor installed for the whole home, hire an electrician. The only safe way to install before the main breaker is to pull the meter.

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Agreed. And often this will get you in trouble with the utility co if you do it yourself :smile:.

No argument here about doing it as safely as possible … probably why I haven’t installed mine yet (I also don’t have an outlet very near my panel in order to run the 5v power supply and not need batteries).

My personal opinion?: Assess the risk. If your panel is not very crowded and you have room to (a) check that none of the circuit cables are loose, and (b) fit the clamps around the mains without going very near exposed ends; then you may feel safe doing it. … © Flip the main breaker so that you know none of the other circuits in the box are hot and can pay all your attention to the 2 main wires.

BTW: When examining my panel, indeed I found that the screw on one of the mains was loose; probably just happened over time; natural vibrations; or poor installation. So, fact is, I could have been electrocuted in the face one random day while resetting a tripped fuse. Life is unpredictable.

My philosophy: You need to respect the situation. It’s up to you whether or not to fear it.

If you want to monitor two appliances and one or both are 240 you can put a single clamp on one leg and just double the measurement you see on the display. It might be a little off depending on the appliance. If the appliance has no neutral (like a water heater or AC) it will be fairly accurate, because it puts the same load on both legs. But if you put it on say a dryer the heating elements will be balanced across both legs but the motor might only be on one leg. The heating elements will be the bulk of the usage.

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