Since 2005 there have been 2 updates to the NEC code. The latest update was in 2008 which states that a deck must have at least 1 outlet if the deck is at least 20 sf. The outlet has to be no more than 6.5 feet higher that the floor of the deck.
The receptacle must be water protected by a weatherproof cover at all times and have a GFIC trip button.
NEC adopted the new rules because of the extensive use of extension cords to power electrical appliances.
Extension cords are known to cause property damage due electrical fires. They can cause personal injury due to people tripping on the cord and electrical shock and shorts due to overloading the extension cords wires gauge.
Henry, do you have a question?
I think it was meant for the student section.