three-phase and single-phase, they’re connected to the secondary of the distribution electrical device. This way, they get three-phase Star association (3-Phase, four Wire System with Neutral Wire). within the Star association, 3 section Line to Line (Phase to Phase) voltage square measure 415V AC (in US, 208V) and Single section Line to Neutral (Phase to Neutral), there square measure 230V AC (120V within the US).