I have a three phase derived setup here with my IoTaWatt, and when I compare the cumulative kWh readings in IoTa, they are much lower than what I see on my utility meter. I have checked all three phases are correct, when I change phase B or C to a different phase the reading drops down quite a bit, and even goes negative, so I am sure those are set correctly. I am using the PowerTech MP-3027 A/C adaptor, which is configured correctly in the IoTa setup, and the CTs are the 100A 16mm units. I plan to install the IoTa with a full three phase reference system using three reference transformers, but that will be down down the track.
To troubleshoot further, I will borrow my eletrician mates RMS meter with it’s own CT clamp, and compare the current readings between IoTa and the Fluke meter, then verify the voltage readings in IoTa match the Fluke as well.
I haven’t had the IoTa for a full billing cycle yet, which is three months, so I will confirm it once I have enough data to compare, but in the meantime, is there anything obvious that I should check? Rough calculations show the IoTa is reading somewhere around half the kWh of the utility meters (780kWh vs ~1500kWh)