If you want the whole house, you’ll need to crack the box to get at the phase split as it comes in.
If you want to track individual circuits, you should be able to do it outside the box. It will work with single phase at least,but not sure about dual-phase; but those are usually reserved for heavy appliances like stoves and dryers.
Do it in the winter.
Watch 12 hours of movies, have 8 hours of sleep, go outside for the 4 hours of sun.