Identify Service Amperage and Voltage

What happens here

The discussion shifts to the characteristics of the electrical service. The apprentice correctly identifies it as a 400-amp service, which is visually indicated by the large 4-inch conduit feeding the main panel. The master electrician then points out that the service voltage is 120/208 volts. He remarks that this voltage configuration is unusual for a commercial service of this size, as typically, commercial installations would utilize a higher voltage, such as 480 volts, for greater efficiency and capacity.

Goal: Determine the service amperage and voltage based on visual cues (conduit size) and electrical standards.