The transmitter can accept up to 3 different current sensing clamps.
The signals from those current sensors will be added together inside the Transmitter and the monitor will reflect the total sensed usage.
To monitor ALL 3 Phases separately will require 3 Separate units or an OWL Intuition-lc system.
The Voltage setting required for the OWL +USB when being used with 3 Phases will depend on the installation being monitored.
If the Power is being used L-N as 3 Separate Power supplies then each will be 230V
If the Power is being used in Delta format connection 3 Phase then set to 230V
If the Power is being used in Star Formation 3 Phases then the Voltage needs to be 400V