A wire tracker is used to locate and identify wires and cables, find circuit breakers, and detect faults in electrical systems. It consists of a transmitter that sends a signal down a wire and a receiver that detects that signal, allowing electricians and technicians to trace wires in walls, floors, or bundles without cutting into them. Other uses include testing network cable continuity and checking for shorts, and locating buried lines like water or gas pipes with the help of a tracer wire.