Why do we need 277 volt light bulbs?

Most residential lighting applications require no more than 120 volt (V) bulbs. What, then, is a 277V light bulb, and what is the point of it?

Let’s start by explaining what voltage is. Voltage, by definition, is an electrical potential difference or the difference in electrical potential between two places, and the unit of measurement for this difference is called the volt. In a nutshell, voltage is basically what makes electrical charges move. It is an electromotive force, or “push”, that causes charges to travel within an electrical conductor.

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.

Vintage voltmeter.

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.

The Compact Fluorescent (CFL) 277 Volt light bulb is one of the most energy efficient bulbs available. These types of CFL bulbs use 75% less power than an incandescent equivalent while producing the same lumens (brightness). Add in the fact that CFL bulbs have an incredibly long lifespan, and you have a great combination for your choice in lighting options. One drawback is that CFL bulbs are not rated for use in enclosed fixtures due to the high heat levels produced. The heat can cause damage to the fixture if there is nowhere for the heat to escape and can drastically reduce the bulb’s life. CFL’s are also not recommended for use with dimmers or sensors due to how fluorescent technology operates.

There are several lighting choices available for 277V bulbs in addition to CFLs, including Linear LEDs, PAR38 LEDs, and A-shape LEDs. GoodBulb offers a range of options in these categories for use with any project requiring 277V input. Check out our catalog or speak with a lighting specialist today for help choosing the right lights for your project.