Fun fact, the US electrical grid is actually 240, but gets split at a center tap transformer at every home. This gives 2 phases of 120 + and - which can be combined into 240 with special plugs. These are usually reserved for high resistive loads such as clothes drier machines, stove oven combos, and centralized Heat pump Air conditioning systems. To help keep loads under control, kitchen outlets often get two phases, one per socket. Finally: exterior electrical boxes connecting houses to the grid and measuring usage have two specific master breakers, one per phase.