From the FAQ:
Will the Vue work in countries outside the US?
The Vue is designed to work with 60Hz 120V/240V split-phase electrical systems. If your system differs from this, the Vue will still work. However, our wattage conversions will not be appropriate since we assume the system operates at 120V. Therefore, the usage displayed in the app will be off by a factor of the difference in voltage. Additionally, the Vue ships with a 120V to 12V power supply. Connecting it to voltages higher than 120V will likely cause the power supply to fail.