A: Yes, it uses a shunt resistor (Class 1 accuracy, +/- 1%). It is accurate enough for billing estimation but not for revenue-grade metering.
To configure your TOMZN TOVPD1-60-EC, press and hold the button for 3 seconds. Once the screen begins to flash, use the UP and DOWN keys to adjust the parameters. Press SET briefly to move to the next "Step." 1. Over-Voltage Protection (A1) Display: A1 Range: 230V–300V (Default: 270V) tomzn tovpd1-60-ec manual
Look for the technical support email on the TOMZN official store page (AliExpress or Amazon). Provide them with the "TOVPD1-60-EC" model and your firmware version (found in the Smart Life app under "Device Information"). A: Yes, it uses a shunt resistor (Class 1 accuracy, +/- 1%)