Shelly 3EM - strange behavior on one phase

Hello,

I have installed the 3EM for 3 phases monitor. I don't have any returned energy (so no solar panels, or something similar), so I guess I should never read some negative value ?

I have 2 issues:

- For phase C (grey wire), most of the time, on "idle" (by idle, I mean no big load plugged, like hoven, iron, etc) I have negative value. When there is load, values are corrects. I assume the wiring is correct since it's working fine when there is load. See a small graph (from home assistant). What could be the problem ?

- For phase A (brown wire), the behavior is quite strange (at least to me). On "idle" the value sounds correct (something like 50W). But when there is load.. it depends. I tried different outlets (outlets are grouped behind "sub breakers", you can see them in the picture: "A", "B", etc) around the house with a vacuum cleaner. Depending on the outlet the vacuum cleaner is plugged, sometimes values are correct (= correct regarding the power AND positive), sometimes, they aren't (=negative value BUT absolute value is correct regarding the power). So for example, I have a 1000w vacuum cleaner plugged on one outlet, the power (from the shelly 3EM) is 1000W for that phase, on another outlet, the power is -1000W. What could cause the problem ?

Here is a picture of where are the clamps (these 3 clamped wires are coming from electricity company box):

Does anybody have any tips for me ?

Thanks,

Thomas

I spent part of the day testing wires. I first thought my electrician didn't follow colour convention and then I discovered that here in Belgium and with 3x330V only, there is no real colour convention..

So first I just "dumbly" follow color to wire the 3EM. I just rewire it following label (L1, L2, and L3) and not color and it worked !