text: why some countries in the world use 220 volts 50 hz while some 115 volts 60 hz? why some countries in the world use 220 volts 50 hz while some 115 volts 60 hz? e.g. india use former and usa us later for home electricity why there is no universal standardization for it? "the choice of supply voltage is governed more by tradition than by optimization of the distribution system".  see the link below.