Electrical power distribution comprises feeders, distributors, and service mains.
Feeders
The feeder is the electrical conductor that connects the sub-station to the area where power is to be distributed. The current in a feeder remains same since, no tappings are taken from the feeder. While designing a feeder the main consideration is the current carrying capacity. In the figure below feeder is indicated using blue color.
Distributor
A distributor is the electrical conductor from which tapping are taken for supply to the consumers. From a feeder many tappings are taken, due to which current through a distributor is not constant. While designing distributors, power engineers are primarily concerned with voltage drop. Since a voltage variation higher than ± 6% is undesired. In the figure distributor is indicated in green lines.
Service mains
The service mains are small electrical conductor cables that connect the distributor to the consumers’ terminals. In the figure below service mains are indicated in red color. The consumers loads are indicated in golden colors.
