I think this is your only practical option and it could work (AFAIK) but with caveats:
- Sense is calibrating (to 208V/120deg phases in my case, as @kevin1 quoted ) based on your input voltage across both legs (although only powered from one), right @JustinAtSense?
- The panels are going to have a mix of use of the three phases, 120V on any given phase for single phase circuits (devices/breakers); 208V for dual-phase. And let’s assume you don’t have any 3-phase motors or gear … or do you? Anyway, detection on any X-Z or Y-Z phase is not going to happen.
If you’re OK with just clocking the watts it could work (inelegantly) but, thinking out loud, there is a way to perhaps do that more efficiently, using Sense, if you can be “upstream” on the panel feed wires, where you can physically clamp multiple wires … current and wire gauge-permitting you could use 4 Senses for a total of 8 “dedicated” (Flex) CTs. Clamp the CT around the 3 (live) wires in each panel. You’d probably want to create a dedicated kind of “passthrough” panel for all that with the Senses in it and so you’re looking at some tricky “local electrical code” issues! I’d go on about using the Main CTs for redundancy or selective detection but you get the idea.
FYI: A Fluke 435 is a nice tool and something an electrician might use to temporarily log and balance phases and whatnot. That’s not something most can afford to leave “dedicated” but at some point in all the fiddle there are situations where a Fluke 1736 or 1738 could interesting.
I agree with @pswired, you have more commercial options.
Monnit, as @ben points out, is a possibility and I use their sensors (very effectively) in a number of building monitoring situations but not for current/energy monitoring due to expense and limited capability. That said, if you care about heat/fire/water they are my go-to: e.g. I’ve got temperature and humidity sensors in racks and panels and water sensors in electrical rooms. Typically these are redundant with sensors that are often built into commercial gear. If you are dealing with a bunch of expensive and/or critical gear and NOT doing redundant monitoring then you are probably doing something wrong. Sensors tend to pay for themselves by saving during a single “event”.