What is the minimum size conductor allowed in commercial buildings for branch circuits up to 2000 volts?

The minimum size conductor allowed in commercial buildings for branch circuits up to 2000 volts is indeed 14 AWG. This gauge is generally accepted for conducting electrical current in residential and commercial settings, especially for general-purpose circuits that are not subjected to significant overload.

The National Electrical Code (NEC) outlines standards for conductor sizes based on factors such as circuit load, length, and application. For branch circuits that carry 15 or 20 amperes, which are common in commercial settings, 14 AWG is sufficient to handle the current effectively without posing a risk of overheating or voltage drop under standard conditions.

While larger gauges like 12 AWG and 10 AWG can handle higher currents and are sometimes used for specific applications, the minimum requirement allows for 14 AWG in these general circumstances. Lower gauges, such as 16 AWG, may not safely carry the current loads typically expected in commercial environments, which is why they are not acceptable for this application.