Which of the following is NOT a common distribution system?

The choice indicating 100/200 V, 3 phase, 2 wire is not a common distribution system primarily due to the configuration and voltage level. Standard three-phase systems typically have a neutral conductor, which is represented by four wires in configurations like 120/208 V or 277/480 V. In a three-phase system, the presence of a two-wire configuration does not facilitate the common distribution of power effectively, as three-phase loads require a balanced distribution that a two-wire system cannot provide.

Additionally, typical voltage levels for three-phase systems are higher and generally include voltages like 208 V, 400 V, or 480 V in commercial and industrial settings. The specified voltage levels of 100/200 V fall outside recognized standards, contributing to the characterization of this choice as uncommon or improper for standard distribution networks. Hence, this option stands out as not aligning with typical distribution system designs used in electrical installations.