An electric horizontal directional drilling machine. The purchase and distribution of media by these methods and systems are not only secure but also controlled. The open loop transfer function for the feedback loop contains only one pole; because no phase-locked loop or other complex circuit introducing multiple poles within the feedback loop are employed, the time constant tuning filter is intrinsically stable. Alternatively, units associated with the premises power distribution lines may be arranged in a master-slave configuration, with a first unit configured to verify the functioning of two-way communication with the second unit. Additionally, registering the user can comprise registering the user’s mobile device, for example, to provide multi-factor authentication. In addition, an inner corrugated tube 27 is formed so as to be inserted from one end to the other end of the outer corrugated tube 26 with the high voltage cable 22 accommodated therein.