Explain the comparison between dc 2 wire system and ac single phase 2 wire system and ac 3 phase 3 wire system and ac 3 phase 4 wire system?

Answer 1

of all of dem 3 phase 3 wire is most economical as it uses less conductor dan in 4 wire system, 3 phase 3 wire is used in transmission and 4 wire in distribution as it has 3 live and one neutral wire.

3 phase needs lesser conductor size than 2 phase 4 wire for the same power.

3 wire dc feeder is more economical than 2 wire dc feeder for the same power.

that was all i cud get..... hope u find it a lil helpful.