Editing Extension cord (section)

==Regulations==

=== National Electrical Code (US)===
In the United States the domestic voltage is 120&nbsp;V, and the [[National Electrical Code]] (NEC) prohibits the use of extension cords in a 20&nbsp;A circuit unless they are of 16&nbsp;[[American wire gauge|AWG]] or larger diameter (for example, 14&nbsp;AWG or 12&nbsp;AWG).

As with other flexible cords, the NEC also prohibits their use where attached to building surfaces, concealed inside structures (walls, floors, ceilings), above suspended ceilings, or run through holes or other openings (windows, doors) in structures. The NEC does contain exceptions although they are very limited.

{| style="float: right; margin-left: 1em;" border="1" cellspacing="0" cellpadding="5"
|+ U.S. extension cord specifications<ref>Coleman Cable Inc.</ref>
! Conductor<br>[[American wire gauge|gauge]]/wires
! Max<br>current
! colspan=2 | Max<br>length
|-
| rowspan="2" | 16/2
| 13&nbsp;A
| {{convert|50|ft|abbr=on|disp=table}}
|-
| 10&nbsp;A
| {{convert|100|ft|abbr=on|disp=table}}
|-
| rowspan="2" | 16/3
| 13&nbsp;A
| {{convert|50|ft|abbr=on|disp=table}}
|-
| 10&nbsp;A
| {{convert|100|ft|abbr=on|disp=table}}
|-
| rowspan="2" | 14/3
| 15&nbsp;A
| {{convert|50|ft|abbr=on|disp=table}}
|-
| 13&nbsp;A
| {{convert|100|ft|abbr=on|disp=table}}
|-
| 12/3
| 15&nbsp;A
| {{convert|100|ft|abbr=on|disp=table}}
|-
| 10/3
| 15&nbsp;A
| {{convert|100|ft|abbr=on|disp=table}}
|-
|}

[[File:Counterfeit extension cord 06256.jpg|thumb|Cheap extension cord with counterfeit silver [[UL Label]] may be a fire hazard]]
Within the United States, [[Underwriters Laboratories]] certifies extension cords as complying with the NEC.  Key standards are UL 817<ref>{{cite web|title=Standard for Cord Sets and Power-Supply Cords|url=http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=0817.html|access-date=2011-09-26|author=UL 817|date=2001-03-16|archive-url=https://web.archive.org/web/20140201214708/http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=0817.html|archive-date=2014-02-01|url-status=dead}}</ref> for the entire extension cord, and UL 62<ref>{{cite web|title=Flexible Cords and Cables|url=http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=0062.html|access-date=2011-09-26|author=UL 62|date=2010-05-18|archive-url=https://web.archive.org/web/20120314015315/http://ulstandardsinfonet.ul.com/scopes/scopes.asp?fn=0062.html|archive-date=2012-03-14|url-status=dead}}</ref> for the electrical cabling itself.  The United States [[General Services Administration]] also maintains a standard for extension cords, J-C-1270,<ref>{{cite web|title=Cable Assembly, Power, Electrical|url=https://assist.daps.dla.mil/quicksearch/basic_profile.cfm?ident_number=48030|archive-url=https://archive.today/20121212204050/https://assist.daps.dla.mil/quicksearch/basic_profile.cfm?ident_number=48030|url-status=dead|archive-date=2012-12-12|access-date=2011-09-26|author=J-C-1270B|date=1973-10-05}}</ref> that references the UL standards and provides additional criteria.

The NEC tries to reduce potential fire hazards by requiring that there be a receptacle within {{convert|6|ft}} of every point along the wall in residences, reducing the need for extension cords.{{citation needed|date=September 2014}}  However, even in houses with more receptacles than the code requires, there will sometimes be a need for extension cords.

=== Europe===
[[File:A-Power-cord-or-distribution-unit-IMG_0193.jpg|thumb|An extension cord]]
In Europe and elsewhere where the normal domestic voltage is around 230 V there may be less risk of causing fire through overheating of cables for any given power due to the lower current.  However most European extension reel cables now include an automatic current cut-out to avoid misuse of the cable. This requires manual resetting if excess current is drawn through the cable. (American multi-plug cords also include such a device, but single- or triple-outlet cords do not.)