Caz

I have the same issue on my DB board. Sans solar at this house. Power is restored after load shedding and the RCD trips. 50/50 chance that it will not trip. Did the power on dance yesterday evening at 2:00. If I restore it manually no problem. If I trip the other switches and turn them on one by one, no problem... If I trip the main switch and restore it the RCD is happy. BUT when eskom dies and comes back the RCD trips... So RCD checks if the current returning through neutral is the same as the current going out through live right? So maaybe if the house was off for a while there's something that delays the current returning enough that the RCD trips. Maybe my UPS has some weird effect like that... Though actually I expect motors like fridge/freezer to maybe have that inductive kind of effect. But they're so small...I have replaced RCDs in the past that was just too sensitive which fixed the issue at my brother's house.... So I'm also thinking of replacing this one. Could be that your new one is just too sensitive as well. They're apparently not all the same quality... I have had the same problem at another house with the RCD behind the inverter, but that only happened very rarely