The US, Canada, part of Japan, Taiwan, Cetral America and a few other countries here and there use 110~120 V; 60 Hz as their standard single phase voltage. The 3 phase industrial voltage is 440~480 V. Canada also uses 550~600 V for industries
The rest of the world use 220~240 V; 50 Hz for single phase voltage and 380~415 V for industry.
What is the history of this difference? What is the advantage/disadvantage of one over the other?
What about sockets and plugs? What are the advantages/disadvantages of round pin vs. flatpin?
