Answer for USA, Canada and countries running a 60 Hz supply service.
Assuming you are using the same fixture, and assuming the fixture can operate on either voltage, you will get fewer amps with 208v than with 277v. However, a fixture designed for 208v will probably burn up on 277v, and a fixture designed for 277v will probably not produce any light on 208v.
The two fixtures in reality are quite different. The 277v fixture is using one leg and neutral of a 277/480v 3 phase 4 wire system and the 208v fixture is using 2 legs of a 120/208v 3 phase 4 wire system.
In commercial and industrial installations the 277v fixture is most common.
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480 Volt
277v light fixtures are more efficient to operate and less expensive to install than a 110v fixture of identical wattage. 277v light fixtures are typically installed when 480V 3 Phase primary electric service supplies a commercial or industrial facility. 277v lighting circuits are single phase circuits using one of the 480v primary phases (A,B & C) to Neutral. The higher voltage allows more fixtures per circuit using smaller conductors and longer runs typically required in warehouse lighting applications. ( Amps = Watts/Volts: 400W/277V Fixture = 1.4 Amps, 400W/110V fixture = 3.6 Amps) With 480V 3 Phase primary service, 110V Single Phase power is created using a Step-down transformer. The voltage transformation process consumes power (kWh) and the 277V fixture will consume less kWh than a 110V fixture if identical wattage, especially in fixtures with ballasts such as fluorescent or High Intensity Discharge (HID), like Sodium, Metal Halide or Mercury Vapor.
no ----------------------------------------------------------------------------------- Stepdown transformer. More expensive than buying the correct light fixture. Y-THINK-Y
No...that's too much voltage, and 277v is normally three-phase power.
That's 277 volts of alternating current. This is typically one phase of a 480v 3 phase system. Don't worry that 3 x 277 adds up to more than 480v. A 277v line is typically one phase of a 480v 3 phase system.