The utility model discloses a single-core wire tracker for a power cable. The single-core wire tracker comprises a power supply, a trigger switch and a relay, wherein the relay comprises a normally closed node and a normally open node. One end of the normally closed node is connected with the anode of the power supply, and the other end of the normally closed node is connected with the trigger switch. When a core is not electrified, the normally closed node is not operated, and when the core is electrified, the normally closed node is opened. One end of the normally open node is connected with the anode of the power supply, and the other end of the normally open node is connected with the cathode of the power supply. When the core is not electrified, the normally open node is not operated, and when the normally open node is electrified, the normally open node is closed. One end of the trigger switch is connected with the cathode of the power supply, and the other end of the trigger switch is connected with the normally closed node. The single-core wire tracker can prevent the core from being directly grounded during wire inspection, and improves security of wire inspection.