Split-phase electric power
（重定向自Split phase）
![Cutaway of a single-phase transformer. The single-phase primary wire is seen on the right toward the front. Split-phase secondary wires are toward the back of this transformer.](/Images/godic/202502/12/Pole_mounted_single-phase_transformer_cutaway5118.jpg")
![Fig. 1](/Images/godic/202502/12/Split_phase25118.png")
![Fig. 2](/Images/godic/202502/12/Vector_diag_3_wire_single_phase.svg5118.png")
![Fig. 4](/Images/godic/202502/12/3wire_resistive_loads.svg5118.png")
A split-phase or single-phase three-wire system is a type of single-phase electric power distribution. It is the AC equivalent of the original Edison three-wire direct-current system. Its primary advantage is that it saves conductor material over a single-ended single-phase system, while only requiring single phase on the supply side of the distribution transformer.