What is a main line distribution circuit composed of?

A main line distribution circuit is primarily designed to deliver electrical power from the substation to various local distribution points and can serve both residential and industrial consumers. It typically consists of three-phase systems, which allow for a balanced load and efficient power distribution. The presence of a neutral wire in addition to the three phases helps to complete the circuit and provide a return path for current, catering to single-phase loads as well.

The configuration of three phases provides several benefits, including improved voltage stability and reduced conductor size for the same power load when compared to single-phase systems. Using just three-phase configurations is common, especially in industrial applications, as they can efficiently manage higher power demands.

In summary, the correct answer reflects the standard design of main line distribution circuits, emphasizing the incorporation of three phases and the option for a neutral or just three-phase configurations to effectively serve diverse electrical loads.