277 volt
- Thread starter domnic
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Well, 120V as a standard goes all the way back to the beginning of electric lighting, starting with Edison using 110VDC, then Westinghouse/Tesla using 110VAC so that people could continue using Edison's bulbs. How it got from 110 to 120V is just cream age from standardization as time went on and electricity use expanded.
277V is just because of the convenience in an industrial facility that uses 480V from a Wye transformer, because 480V line to neutral is 277. So if your plant is already using 480V for motors, you run a line and neutral to the lighting and you don't have to go buy another transformer. Lower current than 120V too, so less voltage drop with the long distances of a factory or warehouse.
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