Negative measured values at low load on one phase

[Boris_3em]

Hello everyone

I have wired the Shelly pro 3EM correctly: The voltage is tapped at the respective phase to which the corresponding clamp is also connected. The direction of the arrow on the clamps was also observed. The phase monitoring of the Shelly does not report any faults. The clamps are installed upstream of the fuses so that the Shelly's own consumption is also measured. The consumption on phases A and B is displayed correctly. If no load is connected on phase C and only the Shelly is supplied with power, the consumption is displayed as negative (approx. -2.3W). If I connect a load (11 W) to phase C, the consumption is correctly displayed as positive (only 11 W), but the Shelly's own consumption, which should actually be added, is then missing. If I switch the load off again, the display reverts to the old pattern (-2.3W).

Does anyone have any ideas as to why this could be?

 

[thgoebel]

Ignore it! In no load condition, low wattages are displayed with no or very small power factors. This is called ‚meter creeping‘.

[Boris_3em]

There is actually a load, namely the shelly's own consumption. I assume the Shelly should actually be able to measure its own consumption correctly, right? Like here for example in 8:28.