Three-phase power is a three-wire Alternating Current (A/C) power circuit. Most US commercial buildings use a 3 Phase 4 Wire 208Y/120V power arrangement because of its power density and flexibility. Compared to single-phase, a three-phase power arrangement provides 1.732 (the square root of 3) times more power with the same current and provides (7) power circuits.
At the moment, Sense can only monitor two of the three phases in these panel setups. The most obvious limitation right now is that the hardware only includes two sensors for current monitoring and two voltage monitoring wires. While the workaround is to monitor two of the three phases, it is important to realize that this is not an ideal scenario. There will be one phase that is left entirely unmonitored by Sense and the customer must be OK with this.
A scenario where this works best is if the installation is in a condo or apartment unit. Typically, the main panel for the building is a three-phase, however, each unit’s subpanel is receiving power from only two of the three phases. In this case, the setup would look the same as a split-phase panel setup. Simply make a note of this in the Sense Installer app.