The device is suitable for phase comparison of systems to be connected on live MV networks. The device set consists of a transmitter and a receiver unit with radio frequency communication. The receiver unit gives information via different light and sound signals whether the phase detected is the same or differs from the one detected by the transmitter. The comparison is continuous, there is no time limit. The communication distance of the two units is 15-20 m. The devices shall be used with the appropriate manipulating rods tested for the given voltage levels.