ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades "Esoteric" countries and their wiring practices?

It does in those rare cases where the voltage is at the high or low end of the allowed interval. 220 +/-10% means that the low voltage is 198V. Enough to destroy 240V motors. 240 +/-10% means a high voltage is 264V, which is enough to overheat and destroy 220V ballasts and electronics. If it's poorly designed, it can catch fire. Therefore, the nominal voltage and the tolerances do matter.

(Side note: Australia and the UK had 240V +/- 6%, and the US and Canada also have very tight tolerances. However, there is little point in having tight tolerances if other countries don't. Appliances will then have be made to accomodate the wider tolerances anyway)