page_title: AC power plugs and sockets
section_title: JIS C 8303, Class II unearthed
hierarchical_section_title: AC power plugs and sockets / Types in present use / North American and IEC 60906-2 / JIS C 8303, Class II unearthed
context_page_description: AC power plugs and sockets connect electric equipment to the alternating current power supply in buildings and at other sites. Electrical plugs and sockets differ from one another in voltage and current rating, shape, size, and connector type. Different standard systems of plugs and sockets are used around the world.
  Plugs and sockets for portable appliances became available in the 1880s, to replace connections to light sockets with wall-mounted outlets. A proliferation of types developed for both convenience and protection from electrical injury. Today there are about 20 types in common use around the world, and many obsolete socket types are found in older buildings. Coordination of technical standards has allowed some types of plug to be used across large regions to facilitate trade in electrical appliances, and for the convenience of travellers and consumers of imported electrical goods.
  Some multi-standard sockets allow use of several types of plug; improvised or unapproved adaptors between incompatible sockets and plugs may not provide the full safety and performance of an approved socket-plug combination.
context_section_description: The Japanese plug and socket appear physically identical to NEMA 1-15. The Japanese system incorporates stricter dimensional requirements for the plug housing, different marking requirements, and mandatory testing and approval by METI or JIS.
  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 V, and the frequency is either 50 Hz (East Japan) or 60 Hz (West Japan) depending on whether the customer is located on the Osaka or Tokyo grid. Therefore, some North American devices which can be physically plugged into Japanese sockets may not function properly.
caption: Japanese socket with earth post, for a washing machine
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