BS 1363 three-pin .28rectangular.29 plugs and sockets AC power plugs and sockets: British and related types

1 bs 1363 three-pin (rectangular) plugs , sockets

1.1 history

1.1.1 chronology


1.2 bs 1363-1 rewirable , non-rewirable 13 a fused plugs

1.2.1 nominal dimensions
1.2.2 pin insulation
1.2.3 fuses
1.2.4 other safety features
1.2.5 ratings
1.2.6 counterfeits , non-standard plugs


1.3 bs 1363-2 13 a switched , unswitched socket-outlets

1.3.1 shutters
1.3.2 socket covers


1.4 bs 1363-3 adaptors

1.4.1 shaver adaptors


1.5 bs 1363-4 13 a fused connection units switched , unswitched
1.6 bs 1363-5 13 a fused conversion plugs
1.7 bs 1363 variations

1.7.1 folding plugs
1.7.2 variant pin configurations

bs 1363 three-pin (rectangular) plugs , sockets

left: typical moulded bs 1363 plug, showing fuse access underside of plug. right: typical rewireable plug; large central screw releases cover, allowing access terminals , fuse

bs 1363 british standard specifies common single-phase ac power plugs , sockets used in united kingdom. distinctive characteristics of system shutters on line , neutral socket holes, , fuse in plug. has been adopted in many former british overseas territories. bs 1363 introduced in 1947 1 of new standards electrical wiring in united kingdom used post-war reconstruction. plug corresponds type g in iec table. bs 1363 replaced bs 546 plug , socket (which still found in old installations or in special applications such remotely switched lighting). other exceptions use of bs 1363 plugs , sockets include equipment requiring more 13 a, low-power portable equipment (such shavers , toothbrushes) , mains-operated clocks.

history

bs 1363:1947 fused-plugs , shuttered socket-outlets resulted report post-war building studies no. 11, electrical installations

in 1941 lord reith, minister of works , planning, established committees investigate problems affect post-war rebuilding of britain. 1 of these, electrical installations committee, charged study of aspects of electrical installations in buildings. amongst members dame caroline haslett, president of women s engineering society , expert on safety in home. convened in 1942, committee reported in 1944, producing 1 of set of post war building studies guided reconstruction.

the plug , socket-outlet system defined in bs 1363 result of 1 of report s recommendations. britain had used combination of 2 a, 5 a , 15 a round pin sockets. in appendix main report (july 1944), committee proposed new socket-outlet , fused plug should adopted all-purpose domestic standard. main report listed 8 points consider in deciding design of new standard. first of these stated “to ensure safety of young children of considerable importance contacts of socket-outlet should protected shutters or other means, or inherent design of socket-outlet.” others included flush fitting, no need switch, requirements terminals, bottom entry cable, , contact design. appendix added 5 further points of technical detail including requirements plugs not inserted incorrectly, should easy withdraw, , should include fuse.

this requirement new system of plugs , sockets led publishing in 1947 of british standard 1363:1947 fused-plugs , shuttered socket-outlets .

one of other recommendations in report introduction of ring circuit system (often informally called ring main ). in arrangement cable connected fuse, or circuit breaker, in distribution board wired in sequence number of sockets before being terminated @ distribution board, forming ring final circuit. in ring circuit, each socket-outlet supplied current conductors on both sides of loop. contrasts radial system (which used in uk, in same installation) wherein single cable runs out radially, spoke, distribution board serve number of sockets. since fuse or circuit breaker ring circuit has rated maximum current ring carry (30 a or 32 a breaker), additional protection required @ each socket-plug connection. theoretically, such protection have been designated either within socket or within plug. however, ensure protection has rating matched appliance flexible cord fitted plug, fuse rated between 1 a , 13 a incorporated each plug. wired connections may connected ring, , these required include suitably rated fuse. ring circuit in uk requires use of bs 1363 plugs , sockets, bs 1363 system not limited use ring circuits.

chronology

an mk plug original version of standard. note unsleeved line & neutral pins, , inspection hole purpose of making connection of earth conductor visible cover in place (as required bs 1363:1947 clause 15.)

bs 1363 periodically revised, , supplements , amendments issued between major revisions. bs 1363:1984 , earlier versions dealt 13 a plugs , sockets. 1989 onwards standard rearranged 5 parts follows:

part 1: rewirable , non-rewirable 13 a fused plugs
part 2: 13 a switched , unswitched socket-outlets
part 3: adaptors
part 4: 13 a fused connection units: switched , unswitched
part 5: 13 a fused conversion plugs

the following chronology shows revisions, supplements , significant amendments.

june 1947: bs 1363:1947 fused-plugs , shuttered socket-outlets published.

may 1950: bs 1363:1947 amendment 3, title changed specification two-pole , earthing-pin fused-plugs , shuttered socket-outlets a.c. circuits 250 volts (not intended use on d.c. circuits) .

january 1957: bs 1363:1947 amendment 5, added clause permitting operation of shutters simultaneous insertion of 2 or more pins (in addition original method using earth pin).

january 1957: bs 1363:1947 supplement no. 1 added specification surface mounted socket-outlets.

1957: complementary standard published, bs 2814:1957 two-pole , earthing-pin flush-mounted 13-amp switch socket-outlets a.c. circuits 250 volts . separate standard specifying switched version of bs 1363 socket-outlet use bs 1363 plugs.

december 1960: bs 1363:1947 supplement no. 2, added specification resilient plugs.

december 1961: bs 2814:1957 amendment 2, title simplified 13 ampere switch socket-outlets .

1962: bs 2814:1957 supplement no. 1 added specification surface mounted switch outlets.

september 1967: bs 1363:1967 specification 13a plugs, switched , unswitched socket-outlets , boxes published. standard superseded both bs 1363:1947 , bs 2814:1957. 3 a , 13 a fuses specified. resilient plugs included.

august 1984: bs 1363:1984 specification 13 a fused plugs switched , unswitched socket-outlets published. standard superseded bs 1363:1967. changes include introduction of sleeved pins on line , neutral, metric dimensions replacing inches, specifications added non-rewirable plugs , portable socket-outlets. standard aligned, possible, proposed iec standard domestic plugs , socket-outlets.

february 1989: bs 1363-3:1989 13 a plugs socket-outlets , adaptors - part 3: specification adaptors published. new standard covers adaptors use bs 1363 socket-outlets , includes conversion adaptors (those accept plugs of different type), multiway adaptors (those accept more 1 plug, may or may not of different type) , shaver adaptors. adaptors (except accepting not more 2 bs 1363 plugs) require fused. sockets, including other standards, must shuttered.

1994: product approval specification, pas 003:1994, non-rewirable 13 a plugs plastic socket shutter opening pins published. pas 003 allowed design , approval of plugs without earthing intended class ii applications only. superseded bs 1363-1:1995 pas not withdrawn until 23 july 2013.

february 1995: bs 1363-1:1995 13 a plugs socket-outlets adaptors , connection units - part 1: specification rewirable , non-rewirable 13 a fused plugs published. standard, bs 1363-2:1995, supersedes bs 1363:1984. provisions of pas 003 incorporated, plastic pin redesignated isod

september 1995: bs 1363-2:1995 13 a plugs socket-outlets adaptors , connection units - part 2: specification 13 a switched , unswitched socket-outlets published.

september 1995: bs 1363-3:1995 13 a plugs socket-outlets adaptors , connection units - part 3: specification adaptors published. supersedes bs 1363-3:1989

november 1995: bs 1363-4:1995 13 a plugs socket-outlets adaptors , connection units - part 4: specification 13 a fused connection units switched , unswitched published. new standard.

august 2008: bs 1363-5:2008 13 a plugs socket-outlets adaptors , connection units - part 5: specification 13 a fused conversion plugs published. new standard.

may 2012: bs 1363-1:1995 +a4:2012 (title unchanged) published. amended standard allows switches incorporated plugs, , introduced new overload tests amongst others. bs 1363-1:1995 remained current until 31 may 2015.

may 2012: bs 1363-2:1995 +a4:2012 (title unchanged) published. amended standard adds requirement shall not possible operate shutter insertion of two-pin europlug, , introduced new temperature rise tests amongst others. bs 1363-2:1995 remained current until 31 may 2015.

may 2012: bs 1363-4:1995 +a4:2012 (title unchanged) published. minor changes bs 1363-4:1995 remained current until 31 may 2015.

november 2012: bs 1363-3:1995 +a4:2012 (title unchanged) published. amended standard adds requirement shall not possible operate shutter insertion of two-pin europlug, , added specifications switched adaptors amongst others. bs 1363-3:1995 remain current until 31 december 2015.

august 2016: bs 1363-1:2016 (title unchanged) published. added requirements incorporated electronic components , electric vehicle charging. bs 1363-1:1995 +a4:2012 remain current until 31 august 2019.

august 2016: bs 1363-2:2016 (title unchanged) published. added requirements incorporated electronic components , electric vehicle charging. bs 1363-2:1995 +a4:2012 remain current until 31 august 2019.

august 2016: bs 1363-3:2016 (title unchanged) published. added requirements incorporated electronic components. bs 1363-3:1995 +a4:2012 remain current until 31 august 2019.

august 2016: bs 1363-4:2016 (title unchanged) published. minor changes only. bs 1363-4:1995 +a4:2012 remain current until 31 august 2019.

august 2016: bs 1363-5:2016 (title unchanged) published. minor changes only. bs 1363-5:2008 remain current until 31 august 2019.

bs 1363-1 rewirable , non-rewirable 13 a fused plugs

bs 1363 plug, plastic pin insulated shutter opening device (isod) , sleeved pins.

a bs 1363 plug has 2 horizontal, rectangular pins line , neutral, , above these pins, larger, vertical pin earth connection. note, both line , neutral carry current , defined live parts. earth pin serves operate basic shutter mechanism used in many sockets. correct polarity established position of earth pin relative other 2 pins, ensuring line pin connected correct terminal in socket-outlet. moulded plugs unearthed, double-insulated appliances may instead have non-conductive plastic pin (an insulated shutter opening device or isod) same size , shape earth pin, open shutters. when looking @ plug pins earth uppermost lower left pin line, , lower right neutral.

uk consumer protection legislation requires domestic electrical goods sold must provided fitted plugs bs 1363-1. these usually, not necessarily, non-rewirable. rewirable plugs hand-wiring screwdriver commonly available , must provided instructions.

nominal dimensions

bs 1363-1 specifies dimensions of plug pins , disposition respect each other in precise, absolute terms. line , neutral pins have rectangular cross section 6.4 mm 4.0 mm, 17.7 mm long , centres 22.2 mm apart. protective-earth pin rectangular cross section 8.0 mm 4.0 mm, 22.3 mm long , centre line 22.2 mm line/neutral pin centre line. dimensions specified in decimal inches asymmetric tolerances , redefined minimum , maximum metric dimensions in bs 1363:1984.

dimensions chosen provide safe clearance live parts. distance part of line , neutral pins periphery of plug base must not less 9.5 mm. ensures nothing can inserted alongside pin when plug in use, , helps keep fingers away pins. longer earth pin ensures earth path connected before live pins, , remains connected after live pins removed. earth pin large inserted line or neutral sockets mistake.

pin insulation

initially, bs 1363 did not require line , neutral pins have insulating sleeves. plugs made recent revisions of standard have insulated sleeves prevent finger contact pins, , stop metal objects (for example, fallen window blind slats) becoming live if lodged between wall , partly pulled out plug. length of sleeves prevents live contacts being exposed while plug being inserted or removed. method of sleeving pins involving spring-loaded sleeves described in 1967 british patent gb1067870. method adopted described in 1972 british patent gb1292991. plugs such pins available in 1970s, southern electricity/rospa safety pamphlet 1978 encourages use. sleeved pins became required standard in 1984.

fuses

bs 1362 fuses (for bs 1363 plugs)

there 2 common misconceptions purpose of fuse in bs 1363 plug, 1 protects appliance connected plug, , other protects against overloading. in fact fuse there protect flexible cord between plug , appliance under fault conditions (typical british ring circuits can deliver more current appliance flexible power cords can handle). bs 1363 plugs required carry cartridge fuse, must conform bs 1362. post-war building studies no. 11, electrical installations included recommendation provision should made in plug accommodation of cartridge type of fuse 13 amps., , alternatively, 3 amps. fuses of these ratings should interchangeable , readily identified. original bs 1363:1947 specified fuse ratings of 3 a, 7 a , 13 a. current version of fuse standard, bs 1362:1973, allows fuse rating 13 a, 3 a (coloured red) , 13 a (coloured brown) preferred (but not mandated) values when used in plug. other ratings coloured black.

plugs, when supplied separately appliance, should available either 3 a or 13 a fuse fitted. fuses mechanically interchangeable; end user or appliance manufacturer install appropriate rating.

bs 1362 specifies sand-filled ceramic-bodied cylindrical fuses, 1 (25.4 mm) in length, 2 metallic end caps of 1/4 (6.3 mm) diameter , 1/5 long. standard specifies breaking time versus current characteristics 3 a or 13 a fuses.

for 3 a fuses: 0.02–80 s @ 9 a, < 0.1 s @ 20 a , < 0.03 s @ 30 a.
for 13 a fuses: 1–400 s @ 30 a, 0.1–20 s @ 50 a , 0.01–0.2 s @ 100 a.

other safety features

internal wiring.

the plug sides shaped improve grip , make easier remove plug socket-outlet. plug polarised, fuse in line side of supply. flexible cord enters plug bottom, discouraging removal tugging on cable, can damage cable. rewireable plugs must designed can wired in manner prevents strain earth connection before line , neutral connection in event of failure of cord anchorage.

ratings

bs 1363 plugs , sockets rated use @ maximum of 250 v ac , 13 a, exception of non-rewirable plugs have current rating according type of cable connected them , fuse fitted. rating must marked on plug, , in case of non-rewirable plugs marking must value of fuse fitted plug manufacturer in accordance table 2 of standard. typical ratings non-rewirable plugs 3 a, 5 a, 10 a , 13 a.

counterfeits , non-standard plugs

plugs not meet bs 1363 find way uk. of these legal in country manufactured in, not meet bs 1363 - these can brought uk unsuspecting travellers, or people purchasing electrical goods online. can purchased through many uk electrical component distributors. there counterfeit plugs appear meet standards (and marked such) not in fact comply. legislation introduced, last revision in 1994, require plugs sold meet technical standard. counterfeit products regularly seized when found, enforce safety standards , protect approval marks , trademarks of imitated manufacturers. pressure group plugsafe reported in march 2014 since august 2011 thousands of listings of products including illegal plugs had been removed uk websites ebay.co.uk , amazon.co.uk. uk electrical safety council expressed shock @ magnitude of problem , published video showing plug exploding due counterfeit bs 1362 fuse. institution of engineering , technology published information on extent of problem on-line retailers, many advertising replacement cord sets, mobile device chargers, , travel adaptors fraudulently marked bs 1363, , mentioning same sites.

bs 1363-2 13 a switched , unswitched socket-outlets

bs 1363 type electrical socket-outlet. closed shutters block entry of foreign objects

bs 1363 sockets commonly supplied integral switches convenience, switches optional , did not form part of bs 1363 until 1967.

sockets required mate correctly bs 1363 plugs (as opposed dimensions of socket contacts being specified). checked means of use of various gauges specified in standard; these gauges ensure socket contacts correctly positioned , make effective , secure contact plug pins. there no provision establishing interchangeability other device having plug pins incorporated, not covered bs 1363 (for example charger or socket cover) unless device conforms precisely plug pin dimensions specified. insertion of non-compliant plugs may damage sockets. important socket dimensions standard specify are: minimum insertion of 9.6 mm face of socket-outlet first point of contact live part, minimum distance of 9.5 mm line , neutral apertures periphery of socket face, , not exceed dimensions apertures of 7.2 mm x 4.8 mm (line , neutral) , 8.8 mm x 4.8 mm (earth).

when looking @ front of socket earth aperture uppermost (as mounted) lower left aperture neutral contact, , lower right line contact.

shutters

bs 1363 sockets must have shutters on line , neutral contacts prevent insertion of foreign object socket. many sockets use original method of shutters opened earth pin (or plastic isod), longer other pins , hence opening shutters before other pins engage, alone. alternatively, shutters may opened simultaneous insertion of line , neutral pins. later designs require 3 pins inserted simultaneously. use of automatic shutters protection dates @ least 1927. other countries, example usa, gradually requiring sockets protected shutters also.

there specific requirement in standard ensure europlugs , other two-pin plugs may not used bs 1363 sockets shall not possible operate shutter inserting 2-pin plug 3-pin socket-outlet. however, many extension sockets allow plug inserted upside down, i.e. earth pin, defeating shutter mechanism. method used allow europlug (with 2 small round pins , no earth pin) forced open line , neutral ports. uk electrical safety council has drawn attention fire risk associated forcing europlugs bs 1363 sockets.

socket covers

in countries using other socket-outlet types, socket covers sold protect children electrocution inserting objects otherwise unprotected sockets. such covers sold in uk, shutters of bs 1363 socket-outlet make these unnecessary. institution of engineering , technology published article on socket covers mark coles, technical regulations manager, in journal wiring matters . article concludes that: socket-outlets bs 1363 safest in world , have been since first designed in 1940s. socket protectors not regulated safety, therefore, using non-standard system protect long established safe system not sensible. uk government not collect statistics of injury or accidents related use of socket covers.

a uk-based group called fatallyflawed notes none of available socket covers made bs 1363 dimensions , can introduce hazards, either damaging socket contacts or allowing foreign objects inserted live openings. fatallyflawed website displays statement socket-outlet manufacturer mk electric, mk goes great lengths ensure bs 1363 plugs , sockets safe. inserting incorrectly dimensioned products socket-outlet can both damage socket , reduce safety .

as of 30 june 2016 use of socket covers has been banned in premises controlled national health service (nhs) in united kingdom. in october 2016 uk department education confirmed in written answer parliamentary question have brought department of health’s recent alert on dangers associated use of electrical socket covers attention of years providers in england. ‘action children’ has published notice, via foundation years website, use of electrical socket covers in years provision in england. available at: www.foundationyears.org.uk/2016/10/dfe-note-on-the-use-of-electrical-plug-socket-coversinserts-in-early-years-provision-in-england

beama (british electrotechnical , allied manufacturers association) published following statement in june 2017: “beama advises against use of socket-outlet ‘protective’ covers.”

bs 1363-3 adaptors

tripler (left) , doubler (right). tripler has red fuse carrier visible.

plug adaptors permit 2 or more plugs share 1 socket-outlet, or allow use of plug of different type. there several common types, including double- , triple-socket blocks, shaver adaptors, , multi-socket strips. adaptors allow use of non-bs 1363 plugs, or more 2 bs 1363 plugs, must fused. appliances designed not draw more power plug rated for; use of such adaptors, , multi-socketed extension leads, makes possible several appliances connected through single outlet, potential cause dangerous overloads.

shaver adaptors

shaver adaptor

the purpose of these adaptors accept 2 pin plugs of shavers, required marked such. shaver adaptors must have 1 a bs 646 fuse. must accept uk shaver plugs complying bs 4573 , europlugs , american two-pin plugs.

bs 1363-4 13 a fused connection units switched , unswitched

switched , unswitched fused connection units, without sockets, use bs 1362 fuses connection of permanently wired appliances socket-outlet circuit. used in other situations fuse or switch (or both) required, such when feeding lighting off socket-outlet circuit, protect spurs off ring circuit more 1 socket-outlet, , switch feeds otherwise concealed sockets kitchen appliances.

bs 1363-5 13 a fused conversion plugs

conversion plug suitable europlug, empty, europlug inserted , closed

a conversion plug special type of plug suitable connection of non-bs 1363 type plugs (to recognized standard) to bs 1363 sockets. example class 2 appliances mainland europe fitted moulded europlugs. similar converters available variety of other plug types. unlike temporary travel adaptor, conversion plugs, when closed, resemble normal plugs, although larger , squarer. non-bs 1363 plug inserted contacts, , hinged body of conversion plug closed , fixed shut grip plug. there must accessible fuse. conversion plugs may non-reusable (permanently closed) or reusable, in case must impossible open conversion plug without using tool.

the plugs , sockets, etc. (safety) regulations 1994 permit domestic appliances fitted non-bs 1363 plugs supplied in uk conversion plugs fitted, not conversion plugs supplied fitting consumer.

bs 1363 variations
folding plugs

due size of bs 1363 plug, attempts have been made develop compatible folding plug. of july 2014 2 folding plugs have been certified under specially developed asta standards. slimplug complies asta as153 , thinplug complies asta as158. slimplug available part of complete power lead terminating in iec 60320 c7 unpolarized (figure-of-eight) connector. in 2009 thinplug received red dot award product design, first product, power lead terminating in iec 60320 c7 unpolarized (figure-of-eight) connector became available in 2011.

folding plugs

























variant pin configurations

several manufacturers have made deliberately incompatible variants use connection standard plugs not acceptable. common uses include filtered supplies computer equipment , cleaners supplies in public buildings , areas (to prevent visitors plugging in unauthorised equipment). examples 1 design made mk has t-shaped earth pin, , walsall gauge 13 a plug, has each pin rotated 90°, latter being in use on parts of london underground 110 v ac supply. , in british rail offices filtered computer supplies.

variant plugs