From a 99NEC point of view, these sections seem to support outdoor amd highbay >277V lighting with limitations.
§225-7. Lighting Equipment Installed Outdoors. (d) 600 Volts Between Conductors. Circuits
§210-6. Branch-Circuit Voltage Limitations. (d) 600 Volts Between Conductors.
§250-21. Alternating-Current Systems of 50 Volts to 1000 Volts Not Required to Be Grounded.
§410 Part P Special Provisions…
