Editing AC power plugs and sockets (section)

=== North America, Central America and IEC 60906-2<span class="anchor" id="NEMA"></span>  ===
{{Main|NEMA connector}}
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File:Domestic AC Type B USA.jpg|'''Left:''' NEMA&nbsp;5-15 plug. '''Right:''' "Decora"-style duplex socket, with ground-pin up orientation specified in NECA&nbsp;130-2010, centre. Photos are different scale – parallel blades are on {{convert|1/2|in|adj=on|1}} centres.
File:NEMA 5-15 Outlet 120V-15A.jpg|Ordinary duplex socket mounted in ground-pin down orientation.
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Most of North America and Central America, and some of South America, use connectors standardized by the [[National Electrical Manufacturers Association]] (NEMA). The devices are named using the format NEMA n-mmX, where ''n'' is an identifier for the configuration of pins and blades, ''mm'' is the maximum current rating, and ''X'' is either P for plug or R for receptacle. For example, NEMA&nbsp;5-15R is a configuration type&nbsp;5 receptacle supporting 15&nbsp;A. Corresponding ''P'' and ''R'' versions are designed to be mated. Within the series, the arrangement and size of pins will differ, to prevent accidental mating of devices with a higher current draw than the receptacle can support.
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==== NEMA 1-15 ungrounded (Type A) <span class="anchor" id="Type A"></span> ====
[[File:NEMA-1 plug polarized.agr.jpg|NEMA&nbsp;1-15 polarised plug|thumb|upright=0.9]]
[[File:A plug.jpg|NEMA&nbsp;1-15 unpolarised plug|thumb|upright=0.9]]
NEMA-1 plugs have two parallel blades and are rated 15&nbsp;A at 125&nbsp;volts. They provide no ground connection but will fit into a grounding NEMA&nbsp;5-15 receptacle. Early versions were not polarised, but most plugs are polarised today via a wider neutral blade. (Unpolarised [[AC adapter|AC&nbsp;adaptor]]s are a common exception.)

[[Harvey Hubbell]] patented a parallel blade plug in 1913, where the blades were equal width ({{US patent|1064833}}). In 1916 Hubbell received a patent for a polarised version where one blade was both longer and wider than the other ({{US patent|1180648}}), in the polarised version of NEMA&nbsp;1-15, introduced in the 1950s, both blades are the same length, only the width varies.

Ungrounded NEMA-1 outlets are not permitted in new construction in the [[United States]] and [[Canada]], but can still be found in older buildings.

==== NEMA 5-15 grounded (Type B) <span class="anchor" id="Type B"></span> ====
[[File:NEMA-AC-Power-Plugs.jpg|thumb|upright=0.9|Ungrounded vs grounded NEMA plugs]]

The NEMA&nbsp;5-15 plug has two flat parallel blades like NEMA&nbsp;1-15, and a ground (earth) pin.<ref name="NEMA">{{Citation |type =standard |url=http://www.nema.org/stds/wd6.cfm |publisher=NEMA |title=WD6, Dimensional requirements for plugs and receptacles |date=14 April 2016}}</ref> It is rated 15&nbsp;A at 125&nbsp;volts. The ground pin is longer than the live and neutral blades, such that an inserted plug connects to ground before power. The ground hole is officially D-shaped, although some round holes exist and many plugs have round ground pins. Both current-carrying blades on grounding plugs may be narrow, since the ground pin enforces polarity, but outlets have a wider opening for the neutral blade to prevent ungrounded polarized plugs from being put in backwards. This socket is recommended in IEC standard 60906-2 for 120-volt 60&nbsp;Hz installations.

The [[National Electrical Contractors Association]]'s National Electrical Installation Standards (NECA&nbsp;130-2010) recommends that sockets be mounted ''with the ground hole up'', such that an object falling on a partially inserted connector contacts the ground pin first. However, the inverted orientation (with ground pin downwards) is more commonly used. The ground-down orientation has been called the "sad socket", "dismayed face", or "shocked face" by some.<ref>''E.g.'',[https://www.gettyimages.com/photos/sad-socket Sad socket], Getty Images; accessed 2023.09.17. Ernie Smith, '[https://tedium.co/2022/08/19/unusual-electrical-socket-history/ This is my shocked face]', Tedium; accessed 2023.09.17.</ref>

Tamper-resistant sockets may be required in new residential construction, with shutters on the power blade sockets to prevent contact by objects inserted into the socket.<ref>{{Citation |url=http://www.childoutletsafety.org/ |title=Child outlet safety |access-date=21 January 2009 |archive-url=https://web.archive.org/web/20090122051010/http://www.childoutletsafety.org/ |archive-date=22 January 2009 |url-status=live}}</ref>

In [[stage lighting]], this connector is sometimes known as ''PBG'' for ''Parallel Blade with Ground'', ''Edison'' or ''Hubbell'', the name of a common manufacturer.<ref>Drew Campbell ''Technical Film and TV for Nontechnical People'', Skyhorse Publishing Inc., 2002 {{ISBN|1581159986}} Chapter&nbsp;9</ref>

==== NEMA 5-20 ====
[[File:Electrical outlet with label.jpg|thumb|upright=0.6|5-20RA (Canada) or 5-20R (US) T-slot socket mounted with the earth hole up. The neutral connection is the wider T-shaped slot on the right.]]

The NEMA 5-20&nbsp;AP variant has blades perpendicular to each other. The receptacle has a T-slot for the neutral blade which accepts either 15&nbsp;A parallel-blade plugs or 20&nbsp;A plugs.

==== NEMA 14-50 ====
[[File:NEMA 14-50 outlet.jpg|thumb|upright=0.75|NEMA&nbsp;14-50 outlet|left]]

NEMA 14-50 devices are frequently found in [[RV&nbsp;park]]s, since they are used for "[[shore power]]" connections of larger [[recreational vehicle]]s. Also, it was formerly common to connect [[mobile home]]s to utility power via a 14-50 device. Newer applications include [[Tesla, Inc.|Tesla]]'s Mobile Connector for vehicle charging, which formally recommended the installation of a 14-50 receptacle for home use.

==== Other NEMA types ====
240&nbsp;V 20-, 30- and 50-amp rated sockets are often used for high-current appliances such as air conditioners, clothes dryers and electric stoves, respectively.
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==== JIS C 8303, Class II unearthed<span class="anchor" id="Japan"></span> ====
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File:OutletPlug.jpg|Japanese Class&nbsp;II polarized sockets with earth post, for a washing machine (similar to NEMA&nbsp;1-15)
File:Japanese air conditioner electrical outlet.jpg|Japanese 20&nbsp;A socket with earth post and earth connector, for an air conditioner (similar to NEMA&nbsp;5-20)
File:Japanese air conditioner electrical outlet 200v.jpg|Japanese 200&nbsp;V socket with earth slot, for an air conditioner  (similar to NEMA&nbsp;6-20)
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The Japanese Class II plug and socket appear physically identical to NEMA&nbsp;1-15 and also carries 15&nbsp;A. The relevant [[Japanese Industrial Standards]], JIS&nbsp;C&nbsp;8303,<ref name= JIS>{{Citation |title=JIS C 8303-1993, Plugs and Receptacles for Domestic and Similar General Use |publisher=Japanese Standards Association |year=1993}}</ref> imposes stricter dimensional requirements for the plug housing, different marking requirements, and mandatory testing and [[type approval]].

Older Japanese sockets and multi-plug adaptors are unpolarised—the slots in the sockets are the same size—and will accept only unpolarised plugs. Japanese plugs generally fit into most North American sockets without modification, but polarised North American plugs may require adaptors or replacement non-polarised plugs to connect to older Japanese sockets. In Japan the voltage is 100&nbsp;V, and the frequency is either 50&nbsp;Hz (Eastern Japan: Tokyo, Yokohama, Tohoku, Kawasaki, Sapporo, Sendai and Hokkaido) or 60&nbsp;Hz (Western Japan: Osaka, Kyoto, Nagoya, Shikoku, Kyushu and Hiroshima) depending on whether the customer is located on the Osaka or Tokyo grid.<ref>{{cite web |url=https://www.worldstandards.eu/electricity/plug-voltage-by-country/japan/ |title=Power plug, socket & mains voltage in Japan |website=WorldStandards.eu |year=2024 |access-date=6 December 2024}}</ref> Therefore, some North American devices which can be physically plugged into Japanese sockets may not function properly.

==== JIS C 8303, Class I earthed<span class="anchor" id="Japan earthed"></span> ====
Japan also uses a grounded plug similar to the North American NEMA&nbsp;5-15.<ref name=JIS/> However, it is less common than its NEMA&nbsp;1-15 equivalent. Since 2005, new Japanese homes are required to have class&nbsp;I grounded sockets for connecting domestic appliances. This rule does not apply for sockets not intended to be used for domestic appliances, but it is strongly advised to have class I sockets throughout the home.<ref>{{cite web |title=内線規程 改訂のポイントの解説ページ |url=http://www2.panasonic.biz/es/densetsu/naisen_k/wiring1.html |archive-url=https://web.archive.org/web/20120124153041/http://www2.panasonic.biz/es/densetsu/naisen_k/wiring1.html |archive-date=24 January 2012}}</ref>
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