A. Three-phase four-wire
B. Three-phase three-wire
C. Single-phase
D. None of the above
Answer: A. Three-phase four-wire
Explanation:
A distributor is a conductor from which tappings are taken for supply to the consumers.
The current through a distributor is not constant because tappings are taken at various places along its length.
A four-wire system allows you to have phase voltages or line-to-ground voltages.
In a 3 phase 4 wire system, neutral wire carries return current in case any fault occurs in the line there is more flexibility to keep the system running since it may only affect one of the phases.