277V is the preferred input power for most non-residential applications. This is because high voltage lighting produces better efficacy and less current, which in turn means less power is lost due to resistance. As a result, more lighting fixtures can be put onto a circuit because there is less of a concern focused on voltage drop. Higher voltage lights are suited to areas with many fixtures installed close together, like warehouses, retail spaces, schools, medical facilities, hotels, restaurants – you get the idea.
Many commercial and industrial facilities receive their power on a 480/277V, 3 phase, 4 wire system. 277V is the phase-to-neutral stage for 480V phase-to-phase. While large industrial equipment generally uses 480V wiring, industrial-scale lighting utilizes 277V wiring to operate. Industrial-type facilities like higher voltage bulbs like 277V because a transformer is not needed to operate them, and as such you will often see 480/277 voltages together. In turn, 277V light bulbs are then used in these facilities given the significant reduction of costs on energy and construction.