Two-phase system for a smart house?
'2-phase' just means a split 240V feed with a neutral. These feeds are normally called out as L1, L2 and of course N for neutral. Neutral is tied to earth ground at the panel, L1 and L2 are 120V with respect to that neutral and 240V to each other.
Why a split feed? Early light bulbs worked on 110V; ones that ran on 220-240V didn't come until slightly later. So to work around the problem, both Edison and Westinghouse offered split-feed systems, using 110V for lighting and light appliances, and 220V for heavier loads.
This split approach stuck in the US, while Europe, coming on line later than the US, took advantage of newer metal filament bulbs that could run on the higher 220V.
More here: https://electronics360.globalspec.com/article/10511/how-the-u-s-came-to-adapt-120v-while-others-are-using-230v
Virtually all US houses have a split-feed system. The breakers in the panel are divided up between L1 and L2. The breakers alternate legs as they go down the panel.
Some appliances use both L1 and L2, other use only one. High-power feeds like A/C units and dryers use both legs L1 and L2, and will use a linked set of adjacent breakers that pick up L1 and L2 as a pair. Wall plugs and lighting on the other hand only get one leg and a neutral.
You can accurately measure the 240V current by taking the sum of the currents on L1 and L2. Below is an example:

From here: https://help.ekmmetering.com/support/solutions/articles/6000081677-single-phase-3-wire-120-240v-or-120-208v-metering