Editing Extension cord (section)

{{Short description|Type of electrical power cable}}
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[[File:Extension cord.JPG|thumb|right|Yellow [[NEMA connector#NEMA 5|NEMA 5-15]] extension cord]]
[[File:NEMA-1 extension cord.jpg|thumb|NEMA-1 extension cord, common in the United States]]
[[File:Verlengsnoer op haspel (extension cord).jpg|thumb|upright|Extension cord reel (Germany)]]
An '''extension cord''' (US), '''extension cable''', '''power extender''', '''drop cord''', or '''extension lead''' (UK) is a length of flexible electrical [[power cable]] (flex) with a [[AC power plugs and sockets|plug]] on one end and one or more sockets on the other end (usually of the same type as the plug). The term usually refers to [[mains electricity|mains (household AC)]] extensions but is also used to refer to extensions for other types of cabling. If the plug and power outlet are of different types, the term "adapter cord" may be used.  Most extension cords range from around {{Convert|2 to 30|ft}} in length although they are made up to {{Convert|300|ft|4=2}} in length.

The term "extension cord" has been in use since at least 1925.<ref>Addams Stratton McAllister, ''National Directory of Commodity Specifications: Classified and Alphabetical Lists and Brief Descriptions of Existing Commodity Specifications, Issue 65''
 National Bureau of Standards, United States. Bureau of Foreign and Domestic Commerce,	U.S. Government Printing Office, 1925 page 230</ref>

Extension cords come in various colors, lengths, thicknesses and service duties. In general, the more power needed by the appliance, the thicker the cord needs to be (meaning larger [[Electrical conductor|wires]] inside). Cords which will be used outdoors, in wet areas, around oils, or exposed to sunlight for long periods of time should be selected for such specific conditions.
An extension [[reel]] is an extension lead that rolls up, usually into the socket end, which in some cases has more than one socket on it (often 2 or 4). Another type of extension reel hangs near the plug end and permits the user to draw the cord out by grasping the socket end.

Some extension cords also incorporate safety features such as a polarized plug and receptacle, [[ground (power)|grounded]] terminals, a "power-on" indicator, a [[fuse (electrical)|fusible link]], or even a [[residual-current device]] (also known as a ground-fault circuit interrupter or GFCI).

Some cords contain multiple female connectors in close proximity of one another; others have female connectors spaced along the length of the cord. Cords generally contain either grounded or ungrounded connectors. While a grounded male connector can be forced into an ungrounded female socket, this is unsafe.