That's actually a fairly recent (1970s) change, prior to that it was a mix of 50 and 60Hz, 110V and 220V, with no national standard. Also, rural household wiri

That's actually a fairly recent (1970s) change, prior to that it was a mix of 50 and 60Hz, 110V and 220V, with no national standard. Also, rural household wiring is often dogshit all around the world with many places having bad earthing.