|
AC power plugs and sockets are devices that allow electrically operated equipment to be connected to the primary alternating current (AC) power supply in a building. Electrical plugs and sockets differ in voltage and current rating, shape, size and type of connectors. The types used in each country are set by national standards, some of which are listed in the IEC technical report TR 60083, ''Plugs and socket-outlets for domestic and similar general use standardized in member countries of IEC''. Plugs and sockets for portable appliances started becoming available in the 1880s, to replace connections to light sockets with easier to use wall-mounted outlets. A proliferation of types developed to address the issues of convenience and protection from electric shock. Today there are approximately 20 types in common use around the world, and many obsolete socket types are still found in older buildings. Co-ordination of technical standards has allowed some types of plugs to be used over wide 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 different types of plugs; improvised or unapproved adapters between incompatible sockets and plugs may not provide the full safety and performance of an approved socket and plug combination. ==Concepts and terminology== Generally the plug is the movable connector attached to an electrically operated device's mains cable, and the socket is fixed on equipment or a building structure and connected to an energised electrical circuit. The plug has protruding prongs, blades, or pins (referred to as ''male'') that fit into matching slots or holes (called ''female'') in the sockets. Sockets are designed to prevent exposure of bare energised contacts. Sockets may also have protruding exposed contacts, but these are used exclusively for earthing (grounding). To reduce the risk of users accidentally touching energized conductors and thereby experiencing electric shock, plug and socket systems often incorporate safety features in addition to the recessed slots or holes of the energized socket. These may include plugs with insulated sleeves, recessed sockets, sockets with blocking shutters, and sockets designed to accept only compatible plugs inserted in the correct orientation. The term ''plug'' is in general and technical use in all forms of English, common alternatives being ''power plug'',〔(), For Dummies, Charlie Scott, John Wiley & Sons, 2004, p.227 (retrieved 1 March 2013 from Google Books)〕 ''electric plug'',〔(), Physics for AQA, Patrick Fullick, Heinemann, 2001, p.16 (retrieved 1 March 2013 from Google Books)〕 and (in the UK) ''plug top''.〔(), Trevor Linsley, Routledge, 2008, p.37 (retrieved 2 March 2013 from Google Books)〕 The normal technical term (in both British and International English) for an AC power socket is ''socket-outlet'',〔(), IEC/TR 60083 Ed. 6.0, IEC, 2009 (retrieved 1 March 2013 from Techstreet)〕 but in non-technical common use a number of other terms are used. In British English the general term is ''socket,'' but there are numerous common alternatives, including ''power point'', ''plug socket'',〔(), Building Surveys and Reports, James Douglas, John Wiley & Sons, 2010, p.254 (retrieved 1 March 2013 from Google Books)〕 ''wall socket'',〔(), Computer Networking First-Step, Wendell Odom, Cisco Press, 2004, p.38 (retrieved 1 March 2013 from Google Books)〕 and ''wall plug''.〔(), Building Technology: Mechanical and Electrical Systems, Benjamin Stein, John Wiley & Sons, 1997, p.723 (retrieved 1 March 2013 from Google Books)〕 In American English ''receptacle'' and ''outlet'' are common, sometimes with qualifiers such as ''wall outlet'', ''electrical outlet'' and ''electrical receptacle'', all of these sometimes to be found in the same document.〔(), Tamper Resistant Receptacles, Electrical Safety Foundation International, 2009, (retrieved 1 March 2013 from ESFI)〕 A socket may be surrounded by a decorative or protective cover called a ''wall plate'', ''face plate'', ''outlet cover'',〔(''Smart Guide Wiring: step-by-step projects'' ), Fran J. Donegan, Creative Homeowner Press, 2004, p.74 (retrieved 2 February 2012 from Google Books)〕 ''socket cover'', or ''wall cover''. In some designs this is an integral piece with the socket itself, bought and installed as a single unit. Electrical sockets for single phase domestic, commercial and light industrial purposes generally provide either two or three electrical connections to the supply conductors. Two pin sockets normally provide neutral〔(), Electropedia, IEC,(retrieved 1 September 2015)〕 and line〔(), Electropedia, IEC,(retrieved 1 September 2015)〕 connections, both of which carry current and are defined as live parts.〔()''Electrical Inspection Manual, 2011 Edition''], Noel Williams & Jeffrey S Sargent, Jones & Bartlett Publishers, 2012, p.249 (retrieved 3 March 2013 from Google Books)〕〔()''17th Edition IEE Wiring Regulations: Explained and Illustrated''], Brian Scaddan, Routledge, 2011, p.18 (retrieved 6 March 2013 from Google Books)〕 Neutral is usually very near to earth potential, usually being earthed either at the distribution board or at the substation. Line (also known as ''phase'' or ''hot'', and commonly, but technically incorrectly, as ''live'') carries the full supply voltage relative to the neutral (and to earth). Three pin sockets provide, in addition, a ''protective earth''〔()''Electrical Product Safety''], Dave Holland, M.B, Jimmy Tzimenakis, Newnes, 1999, p.58 (retrieved 3 March 2013 from Google Books)〕 connection for exposed metal parts of an appliance. If internal insulation should fail, a short-circuit to the earthed exposed metal parts will hold them at a low potential, and should operate fuses or circuit breakers to isolate the faulty appliance from the supply. Depending on the supply system, some sockets may have two line connections, each at significant voltage to earth and without a neutral pin; for example, a split phase system may have 240 V between line connections each at 120 V with respect to earth ground; but a single-phase receptacle connected to a three-phase system may have, for example, 208 V between contacts and only 120 V between each contact and earth ground. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「AC power plugs and sockets」の詳細全文を読む スポンサード リンク
|