A mains power plug is a mechanical connector that fits into a power point or electrical socket. It has male features, usually brass and often tin or nickel plated, that interface mechanically and electrically to the mains. Such plugs have live, neutral and an optional earth contact. Large appliances with higher voltages use three-phase current and have phase 1, phase 2, phase 3, neutral and an optional earth contact. The reason why we now have over a dozen different styles of plugs and wall outlets is because many countries preferred to develop plug designs of their own, instead of adopting a common standard. In many countries, there is no single standard, with multiple plug designs in use, creating extra complexity and potential safety problems for users.

Read the rest of this article: http://en.wikipedia.org/wiki/Mains_power_plug

Today's selected anniversaries:

* 1813 - The Battle of Lake Erie is fought between the United States and Great Britain. (http://en.wikipedia.org/wiki/Battle_of_Lake_Erie)

* 1960 - Mickey Mantle hit what is thought to be the Major League's longest home run an estimated 643 feet. (http://en.wikipedia.org/wiki/Mickey_Mantle)

* 1974 - Guinea-Bissau's independence from Portugal is officially recognized. (http://en.wikipedia.org/wiki/Guinea-Bissau)

* 2003 - Anna Lindh, the foreign minister of Sweden was stabbed and died of the wounds on September 11. (http://en.wikipedia.org/wiki/Anna_Lindh)

Wikiquote of the day: "The earth is rude, silent, incomprehensible at first; Be not discouraged— keep on— there are divine things, well envelop'd; I swear to you there are divine things more beautiful than words can tell." -- Walt Whitman in Leaves of Grass (http://en.wikiquote.org/wiki/Walt_Whitman)