Schematic Volt

Bridge D4-D7 can only provide  the coil voltage for Ret when  the current through D1-D2 exceeds a certain level, because then series capacitor Ci passes the alternating mains 4 current.
Capacitor C1 may need to be dimensioned otherwise than shown to suit the sensitivity of the relay coil. This is readily effected by connecting  capacitors in parallel until the  coil voltage is high enough for  the relay to operate reliably.   

Over Current Monitor Circuit Diagram