Electrical Distribution Systems

Electrical distribution systems commonly used in Europe and USA

System TypeConfigurationVoltageRegion/UsageDescription
TN3-Phase, 4-Wire 400Y/230 V230/400VEurope and othersStandard European distribution system with neutral conductor
IT3-Phase, 3-Wire 230 V Wye (No neutral)230VNorwayThree-phase system without neutral conductor
Three Phase Three Wire Delta3-Phase, 3-Wire Delta240/400/480/600V+Industrial and utilityUsed for three-phase motor loads in industry and utility power distribution
277/480V Three Phase Four Wire Wye3-Phase, 4-Wire Wye277/480VLarger U.S. facilities (347/600V in western Canada)277V for lighting, 480V for larger loads like HVAC systems
120/240V Three Phase Four Wire Delta3-Phase, 4-Wire Delta120/240VOlder U.S. manufacturing facilitiesDesigned for mostly three-phase motor loads with some single-phase lighting and plug loads
120/240V Single Phase Three WireSingle Phase, 3-Wire120/240VNorth America (residential)Grounded neutral system, Edison system or split-phase, common residential service
120/208V Three Phase Four Wire Wye3-Phase, 4-Wire Wye120/208VNorth America (commercial)Grounded neutral system, most common commercial building electric service in North America