Three-phase alternating current

This is the basic AC voltage used for power transmission and distribution, consisting of three phases with waveforms shifted by 120°C from each other. Because it is the most efficient method for transmitting electricity over long distances from power plants to consumers, it has been the mainstream system from the inception of power transmission and distribution systems to the present. When the transmission distance is long, high voltages such as extra-high voltage are used to reduce line losses. Three wires (four when a neutral wire is included) are used, with loads connected to each phase, and it is necessary to balance the load across each phase.