I am making a 3 Phase power meter using a MICROCHIP IC ATM90E36A. They recommend to use neutral wire as a GND reference to measure voltages at 3 hot legs but in my loads (Air Conditioners) there is no neutral wire. We will only have an earth ground.
According to your expertise : is it safe to use GND earth instead of neutral for the reference ? Will I be violating any of the NEC codes?