The big flaw I see in this what your trying to do, Well the way I look see it, Your feeding your circuit and the current goes higher so the relay turns on and cuts the power then there will be no current flowing so the realy will turn straight back again it would be doing this may be 3 to 4 times a second this could casue the relay to flash and stick, Plus you would need some way of measuring the current which may require a pic-micro, Even if you put a delay before the circuit comes back on but with the inrush current of the circuit been powered up again could cause it to shut down again