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Electrical Distribution Systems

Electrical distribution systems commonly used in Europe and USA


TN 230/400V three phase electrical distribution system

  • 3-Phase, 4-Wire 400Y/230 V
  • used in Europe and others


IT 230V three phase electrical distribution system

  • 3-Phase, 3-Wire 230 V Wye (No neutral)
  • used in Norway

Three Phase Three Wire Delta

three phase delta electrical distribution system

  • used to provide power for three-phase motor loads in industry, and utility power distribution systems
  • voltage typical 240, 400, 480, 600 and higher

277/480V Three Phase Four Wire Wye

277/480V three phase four wire wye electrical distribution system

  • used in larger US facilities with voltage 277/480. 277 volt is used as single phase for lighting and 480 volt is used for larger loads like HVAC systems
  • in western Canada 347/600V is commonly used

120/240V Three Phase Four Wire Delta

120/240V three phase four wire delta high leg electrical distribution system

  • used in older manufacturing facilities with mostly three-phase motor loads and some 120 volt single-phase lighting and plug loads

120/240V Single Phase Three Wire

120/240V single phase three wire electrical distribution system

  • grounded neutral system
  • known as the Edison system, split-phase or center-tapped neutral
  • common as residential service in North America

120/208V Three Phase Four Wire Wye

120/208V three phase four wire wye electrical distribution system

  • grounded neutral system
  • the most common commercial building electric service in North America

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