US doesn’t really have 2 phases. You have a single phase service @ 240V that is split so each side gets 120V. Any of your recognized devices that is 120V is drawing from one leg or the other --> you don’t draw current from both legs on 120V devices. Your 240V devices draw power from each leg.
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Yep… split-phase, though most of us just call it two phase as it’s easier to understand. 
I so badly want Sense to expose the leg/phase information of each device it has detected. I’m going through another support case right now where exposing this in the app would be useful.
@RyanAtSense, when you merge/lock threads with this forum software are you still able to grab stats on how often the same feature is requested?
Yup, the ‘likes’ all get added to the new thread’s ‘like’ count.
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This is a copy / paste from a site talking about that question - load balancing a panel box.
Balancing electrical loads is an important part of laying out the circuits in a household wiring system. It is usually done by electricians when installing a new service panel (breaker box), rewiring a house, or adding multiple circuits during a remodel. In simple terms, an electrical service panel has two sides, and balancing the load is a matter of dividing the circuits evenly between the two sides so that the load, or power draw, is roughly the same on both sides. An unbalanced load occurs when there is significantly more power drawn on one side of the panel than the other. This can lead to overheating of electrical components and possibly overloading the panel.
source : Balancing Electrical Loads
Balancing really does not do a lot as when you build a house or even add an addition you never really know what people will use at one time. Sure it makes sense not to put the washing machine, microwave, 120VAC EV charger and other large users all on one leg, but those are only some of the items you can plan for. You never know what teenage kids are going to use blow driers and hair straighteners and Irons and space heaters all on one leg at once no matter what you pre-plan.
Maybe also report it as an attribute in the data export - L1, L2 and L1L2 for devices that that are connected to both legs.
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When Sense is reporting a new device, it would useful to know if it is a 240V or 120V device.
It would also possibly be useful knowing what phase of the 120V the device is powered from (less important).
I think you know this, since you are monitoring the mains feed and should be able to tell if one, the other, or both have a common current.
Just a thought.
Sorry for spamming this, but I just noticed there is already a product suggestion for the same idea. Great minds and all that…
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I really dig this suggestion to see how balanced I am. Tanks.
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This raises another question. Let’s say that I have a 120 volt device such as a vacuum cleaner that’s moved from room to room frequently. Once sense identifies it on one particular 120 volt leg will it still be identified and appear as the same device when it’s plugged in to a wall receptacle that’s wired on the other 120 volt leg?
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My history says no. I have a dehumidifier that was identified. I moved it to another room in the basement which is on a different branch circuit on the other side of the panel. For the week it was there, it was never picked up. I moved it to yet another room, but one that’s circuits were on the same half of the panel as the first spot. It picked it up the same day after a few on/off cycles.
That makes me think that the models are looking at phase. Or maybe there was something else going on that made it not identifiable in the second location.
Without knowing for sure what circuit I’m on, I have a vacuum that is tracked everywhere I plug it in. In my case, chances are it’s tracking on both legs as one device.
With sense already seeing the voltage and wattage for each phase, can that be an option to graph as well on the screen or on a seperate screen? I ask this because I noticed the loads are not evened out on our panen and to see this could help better distribute them. This is also useful because it appears like we have some minor voltage drops and I would like to correlate these with evens in the house. For example: With LED lights on a dimmer and they are set low, I notice they will blink off occasionally, which leads me to believe the input voltage has dropped and the circuitry can not make use of it when the voltage is below a certain amount.
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click in a day, im logging the voltage but not per phase
I agree it’d be a useful feature. I don’t believe it samples nearly as fast at the CT clamps though, someone may know more.
If you didn’t know, you can see voltage/current and frequency in the app right now. Settings > My Home > Sense Monitor.
Thank you, I am aware of the instant readings for the voltage and wattage for each leg, which is part of the reason I know it shouldn’t be difficult to implement. Also I saw an episode of Ask This Old House, and they went to the sense HQ, while there, the employees were showing some of the data and on the screen was usage for each leg.
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That’s a cool system for solar sharing of data 
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@rich2871
How far “out of balance” between legs does it appear to be?
The reason I ask is because one leg pulling up 0-1800 watts more than the other would be as balanced as you can get.
The way double pole 240 volt breakers and panels are designed pretty much already balances the load. A 240 double pulls from both sides equally, no matter what side of the panel the breaker is inserted.
I have seen it almost 1500W from one to the other. I understand that the 240V breakers should balance between legs, its a combination of all the circuits being used that would be nice to even them out more. Im sure its really not a big deal as its been like this for many years, but more it is my pickiness, or OCDish to get things as good as I can.
Example, many always on loads are on 1 leg, and the heavy current draw appliances are on the other. This would be what I would want to change. I do not know this is the case for sure, just an example of something that could be gathered.
I know there are other devices that can monitor individual breakers and then you can do it , but this is a good starting spot if we could see the history for each leg separately.
I see how doing some balanceing with always on being on one side may help. If you know which breaker are and are not being used, you can swap sides with 2 of them. One will take the others place.
The only reason I wouldn’t do it now is sense will lose detections.
There are very few times a panel is out of balance just because the way they are made. As long as the slots aren’t full on one side and near empty on the other. It really doesn’t matter anyway as a KWH cost the same and there aren’t any safety issues as long as code was followed.