Which statement about low-voltage systems is accurate?

• A. Only up to 120 V are considered LV
• B. LV excludes 277/480 V
• C. LV is generally up to 600 V, and 277/480 V are common in commercial/industrial lighting and distribution
• D. LV includes high-voltage overhead lines

Answer: (C)

Low voltage is defined by the maximum working voltage used by the system, which for most building and industrial wiring is up to 600 volts. Within that range, 480 V three-phase and the 277 V line-to-neutral values (from a 480Y/277 V system) are common in commercial and industrial lighting and distribution. So, this setup is still considered low voltage because all voltages involved stay at or below 600 V, even though 480 V is higher than typical residential voltages. The idea is that voltages well above 600 V are categorized as medium or high voltage and require different equipment and safety standards.