Measure accuracy (France, 220V single phase)


I’m a brand new user of IoTaWatt, and a bit confused with the accuracy I achieve in the first days of use.

Living in France (single phase, 220V, max. 63A), I’ve plugged a CT (AcuCT-H063-100) around the live wire of the main cable, right before the switchboard.

After a few days however, here are the gaps I have vs the provider counter:

IoTaWatt vs provider, kWh:
Nov. 4: 37.6 vs 64.4
Nov. 3: 25.6 vs 44.3
Nov. 2: 31.3 vs 53.6

Obviously something seems wrong in my current (if I may :-)) setup.
Interestingly it’s around ~57-58% of the provider measures, if it could be a hint.

What do you think about that? Am I missing something obvious?

Thanks a lot in advance :slight_smile:

Could you post screenshots of your inputs configuration and status display please?
Also, a picture of your panel showing the CTs installed would be useful.

Thanks @overeasy for your support.

Let me start first with the software screenshots as it’s easier, picture of panel to come later :slight_smile:

Just realized I didn’t change the Input0 (ref) setting. Just changed it to the actual transformer.

Could this lead to such a difference in the measure?

Anyway I will come back in a few days once I get updated measures & comparison vs those from the energy provider.


Do you mean it was configured as the US 120V JW-95001-NA?
Absolutely. The Calibration for the US adapter is 11.14. Yours is 19.12.
11.14 / 19.12 = 0.58.


Haha should be the reason then :innocent:

Will confirm in a few days, thanks for your help!


And after two days I can confirm, results are precisely the same (~.5% gap).

Thanks @overeasy for your swift support!