The utility model provides a passive insulator flashover fault indicator, is including ability device, fairing, control switch device and the electromagnetism indicator asked for. The utility model has the advantages of utilize distribution network phase to earth fault to allow the long period to last operation and the very little characteristics of trouble zero sequence current, through the ability device of asking for that adopts high -magnetic -permeability, acquire the energy and instruct fast faulty insulator from fault current, minimum need 200mA electric current continuously charges and can accomplish the instruction in 70 seconds, neither need additionally provide the power or dispose the battery, energy saving reduce cost, and work is simple, high practicability and high reliability are realized, the installation is convenient non -maintaining, can bear simultaneously the heavy current long period impact and the count that can move 0.5 second at least more than the 5000A in 0.1 second under minimum 50A electric current, consequently can effectively solve in the distribution network because of the insulator flashover lead to single -phase, the heterogeneous earth fault problem of seeking, and be applicable to the power transmission network, offer help for patrolling the line, practice thrift a large amount of human costs and time.