I have a 3 phase + N installation in my home. I've been using the Shelly 3EM since 30/06 and yesterday evening (09/07), all of a sudden phase B started showing a negative power consumption. Before the shift I had a total idle consumption of about 175W, which remains about the same.
Phase A idle consumption has changed from 133W to 322W.
Phase B idle consumption has changed from 20W to -195W.
Phase C hasn't changed and still shows an idle consumption of 7W.
It seems the negative consumption on phase B gets offset by a higher consumption on phase A
I have no solar panels or anything else that produces electricity.
What could be the reason for this behavior?