OP
platty1005
Hi llandrillo you are talking about an RCBO it trips on overcurrent like an MCB and on earth fault like an RCD. Don't concentrate on earth leakage it could be an insulation fault on the final circuit
I suggest start from scratch R1+R2, IR, polarity, Zs then function of the RCBO
Once you are convinced final circuit is OK then look upstream
I suggest start from scratch R1+R2, IR, polarity, Zs then function of the RCBO
Once you are convinced final circuit is OK then look upstream