IoTaWatt is probably the only monitor in it's class that can literally be used to monitor any power system.  It is in use in over 60 countries worldwide.  USA split-phase 120V/240V is easy, but also 230V single-phase as in Europe, 230V three-phase as in homes in Australia, Germany and norway to name a few. Most folks only care if it will work in their situation.  The answer is an unqualified yes.

There are also many commercial/industrial users monitoring high voltage three-phase systems including 277V/480V industrial with 600Amp service using several megaWatt-hours per day - more than most households use in a year.  Then there's a site in Uganda measuring voltage and power used to charge rental electric motorcycles using Solar Energy.

This is all possible because IoTaWatt uses simple external sensors that are available for any and all voltage/power combinations.  Just install, plug into the IoTaWatt and select the sensor type from a dropdown menu in the configuration app.

kwh meters