240v Outlet Best Offer power is used in the US and parts of the world. In the US 120 / 240V 1 Phase 3 Wire is the standard for homes and 240V 3 Phase Open Delta is the standard for small buildings with large loads. In parts of the world 240V Single Phase 2 Wire is the standard for homes. Actual power company voltage varies (220v / 230v / 240v) by region, but to simplify we’re going to focus on 240V. In the US, 240V Power is provided to homes and small buildings as a 120/240V 1P3W power circuit. It provides 120V for light loads (lights, TV, etc.) and 240V for medium loads (Water Heaters, AC Compressors, etc.). In the US, 240V Power is provided to small buildings with large loads as 240V 3 Phase Open Delta. It’s like 120 / 240V but also provides 240V 3 Phase for large loads (Machinery, etc.). It’s often called “Wild Leg” of “High Leg” Delta because one leg (Phase B) is different.