Which of the following voltages is a common low-voltage value used in commercial/industrial contexts?

• A. 277 V
• B. 13,800 V
• C. 2,400 V
• D. 4,160 V

Answer: (A)

In commercial and industrial settings, a common low-voltage setup is a 480Y/277 V three-phase system, where each line to neutral is 277 volts. This makes 277 V a standard voltage for lighting circuits and many control devices, because fixtures and ballasts are designed to run directly off that line-to-neutral voltage from the building’s distribution. The other voltages listed are either much higher-voltage distribution (like 13,800 V) or, while they exist in some equipment, not the typical low-voltage level used inside buildings for general lighting and control. So 277 V is the standard low-voltage value most commonly encountered in commercial/industrial contexts.