Editing Electric power distribution (section)

=== Regional variations ===

====220–240 volt systems====
Most of the world uses 50&nbsp;Hz 220 or 230 V single phase, or  400&nbsp;V three-phase for residential and light industrial services. In this system, the primary distribution network supplies a few substations per area, and the 230&nbsp;V / 400&nbsp;V  power from each substation is directly distributed to end users over a region of normally less than 1&nbsp;km radius. Three [[live wire (electricity)|live (hot) wire]]s and the [[neutral wire|neutral]] are connected to the building for a three phase service. Single-phase distribution, with one live wire and the neutral is used domestically where total loads are light. In Europe, electricity is normally distributed for industry and domestic use by the three-phase, four wire system. This gives a phase-to-phase voltage of {{nowrap|400 volts}} [[Three-phase electric power#Three-wire and four-wire circuits|wye]] service and a single-phase voltage of {{nowrap|230 volts}} between any one phase and neutral.  In the UK a typical urban or suburban low-voltage substation would normally be rated between 150&nbsp;kVA and 1&nbsp;MVA and supply a whole neighbourhood of a few hundred houses. Transformers are typically sized on an average load of 1 to 2&nbsp;kW per household, and the service fuses and cable is sized to allow any one property to draw a peak load of perhaps ten times this.
For industrial customers, 3-phase {{nowrap|690 / 400 volt}} is also available, or may be generated locally.<ref>{{cite web  | url = https://www.en-powered.com/blog/the-bumpy-road-to-energy-deregulation  | title = The Bumpy Road to Energy Deregulation  | publisher = EnPowered  | date = 2016-03-28  | access-date = 2017-04-07  | archive-date = 2017-04-07  | archive-url = https://web.archive.org/web/20170407145323/https://www.en-powered.com/blog/the-bumpy-road-to-energy-deregulation  | url-status = dead  }}</ref> 
Large industrial customers have their own transformer(s) with an input from 11 kV to 220 kV.

==== 100–120 volt systems ====
Most of the Americas use 60&nbsp;Hz AC, the 120/240 volt [[Split-phase electric power|split-phase]] system domestically and three phase for larger installations. North American transformers usually power homes at 240 volts, similar to Europe's 230 volts. It is the split-phase that allows use of 120 volts in the home.

[[File:Power Grid of Japan.svg|thumb|Japan's utility frequencies are {{nowrap|50 Hz}} and {{nowrap|60 Hz}}.]]

In the [[electricity sector in Japan]], the standard voltage is 100&nbsp;V, with both 50 and 60&nbsp;Hz AC frequencies being used. Parts of the country use 50&nbsp;Hz, while other parts use 60&nbsp;Hz.<ref name="JapanTimes20110719">{{Cite news|url=http://www.japantimes.co.jp/news/2011/07/19/reference/japans-incompatible-power-grids/|title=Japan's incompatible power grids|last1=Gordenker|first1=Alice|date=2011-07-19|newspaper=The Japan Times Online|language=en-US|issn=0447-5763|access-date=2016-03-12}}</ref> This is a relic from the 1890s. Some local providers in [[Tokyo]] imported 50&nbsp;Hz German equipment, while the local power providers in [[Osaka]] brought in 60&nbsp;Hz generators from the United States. The grids grew until eventually the entire country was wired. Today the frequency is 50&nbsp;Hz in Eastern Japan (including Tokyo, [[Yokohama]], [[Tōhoku region|Tohoku]], and [[Hokkaido]]) and 60&nbsp;Hz in Western Japan (including [[Nagoya]], [[Osaka]], [[Kyoto]], [[Hiroshima]], [[Shikokuchūō|Shikoku]], and [[Kyushu]]).<ref>{{Cite web|url=http://www.japan-guide.com/e/e2225.html|title=Electricity in Japan|website=Japan-Guide.com|access-date=2016-03-12}}</ref>

Most household appliances are made to work on either frequency. The problem of incompatibility came into the public eye when the [[2011 Tōhoku earthquake and tsunami]] knocked out about a third of the east's capacity, and power in the west could not be fully shared with the east since the country does not have a common frequency.<ref name="JapanTimes20110719" />

There are four [[high-voltage direct current]] (HVDC) converter stations that move power across Japan's AC frequency border. [[Shin Shinano]] is a [[Back-to-back connection#Power transmission|back-to-back]] HVDC facility in [[Japan]] which forms one of four [[frequency changer]] stations that link Japan's western and eastern power grids. The other three are at [[Higashi-Shimizu Frequency Converter|Higashi-Shimizu]], [[Minami-Fukumitsu]] and [[Sakuma Dam#HVDC frequency converter|Sakuma Dam]]. Together they can move up to 1.2 GW of power east or west.<ref>{{Cite web|url=https://spectrum.ieee.org/why-japans-fragmented-grid-cant-cope|title=Why Japan's Fragmented Grid Can't Cope|website=Spectrum.IEEE.org|date=6 April 2011 |access-date=2016-03-12}}</ref>

==== 240 volt systems and 120 volt outlets ====
Most modern North American homes are wired to receive 240 volts from the transformer, and through the use of [[Split-phase electric power|split-phase electrical power]], can have both 120 volt receptacles and 240 volt receptacles. The 120 volts is typically used for lighting and most [[AC power plugs and sockets|wall outlets]]. The 240 volt circuits are typically used for appliances requiring high watt heat output such as ovens and heaters. They may also be used to supply an [[electric car]] charger.