I didn't know AC power was 50 Hz in the UK.,(reply>), +calculon000 Most of the world uses 50 Hz and &gt;200V. 60Hz tends to be for countries using 100-120V, including almost all of North &amp; South America. In the early days it was known that high frequency makes transmission over distance inefficient but low frequency makes lights (especially arc lamps) look horrible. 50-60Hz was the happy medium. Just depends on which business grew to dominate in which location. Standardising it isn't worth the bother.