This paper presents a prototype of equipment used to detect faults in conductor cables employed in power transmission lines. It is able to do visual inspection of the external condition of the conductors and to detect internal faults in its magnetic material core (ACSR cables). The equipment is composed by a mobile unit -a robot -which moves on the line conductor, and by a control unit -a notebook -communicating with each other through radio-frequency transceivers. The equipment design takes electromagnetic (EMI) and radio-frequency (RFI) interference into account, allowing it to be used in live lines, in no energized lines and in ground wires.To verify the equipment's behavior under different situations, several tests have been performed: in laboratory under both no-energized and energized conditions, and in a real live power transmission line. The results obtained are presented. 1