NEMA connector – Wikipedia

Power plugs and receptacles used in North America and some other regions
“ Twist-lock connection ” redirects here. For the device used in intermodal transportation, see Twistlock Ungrounded ( L ) and grounded ( R ) office plugs common North american 125 volt receptacles. All accept a 1-15P plug ; the two on the leave besides accept ground 5-15P plugs ; the second from the left besides accepts 5-20P plugs. The NEMA 5-15R device on the far left is most common ; the two rightmost designs are typically seen in older buildings.

NEMA connectors are power plugs and receptacles used for AC mains electricity in North America and early countries that use the standards set by the US National Electrical Manufacturers Association. NEMA electrify devices are made in current ratings from 15 to 60 amperes ( A ), with electric potential ratings from 125 to 600 volts ( V ). different combinations of touch blade widths, shapes, orientations, and dimensions create non-interchangeable connectors that are unique for each combination of voltage, electric current carry capacity, and grounding system. NEMA 1-15P ( two-pole, no land ) and NEMA 5-15P ( two-pole with reason pin ) plugs are used on common domestic electric equipment, and NEMA 5-15R is the criterion 15-ampere electric receptacle ( release ) found in the United States, and under relevant national standards, in Canada ( CSA C22.2 No. 42[1] ), Mexico ( NMX-J-163-ANCE ) and Japan ( JIS C 8303 ). other plug and receptacle types are for particular purposes or for heavy-duty applications. The dimensional standard for electric connectors is ANSI/NEMA WD-6 and is available from the NEMA web site. [ 2 ]

Precedents [edit ]

In the early days of electrification, residential use was about entirely for miniature, with rooms normally having just a single spot in the center. Along with his light bulb, Thomas Edison developed the Edison screw in the early 1880s, for which he received a apparent in 1881. [ 3 ] The Edison prison guard was very successful, and cursorily became the first de facto standard for electric connection. [ 4 ] In the early 1900s, postpone and floor lamps became more popular, and sockets where mounted on walls for secondary connections. One large disadvantage of screw connectors was that the cord inescapably got twisted after being connected to the receptacle .

Harvey Hubbel ‘s inventions [edit ]

In 1903, Harvey Hubbell filled the U.S. Patent 774,250, for a light bulb socket adapter and plug, besides a standalone receptacle. The adapter was screwed into the light bulb socket, leaving a flat grimace with two holes to handily attach the spark plug. The like patent had a moment design, with a wall attachable receptacle, capable of receiving the same fireplug, frankincense being the beginning socket and plug plan patented in the US. Later in 1904, he changed the design to categoric blades ( a design late incorporated in the NEMA 2 series ), filled under the U.S. Patent 774,251 Both these patents were granted in November 1904. In 1910, Hubbel worked on improving his democratic flat blade design, filled U.S. Patent 1,064,833 in 1912. The modern purpose had parallel blades, a more compress plan and was easier to manufacture. This plan was improved once again in 1915, introducing a polarize plug under the U.S. Patent 1,180,648. The flat blade plug who evolved in the subsequent years to become NEMA 1-15 was born .

other american english manufacturers [edit ]

It is worth noting that in accession to Hubbell ‘s organization, circulated a large variety of unlike plugs and receptacles, some of them compatible with Hubbell ‘s, some not. In 1919, Hubbell unsuccessfully tried to prevent other manufacturers from making receptacles and plugs to the dimensions used by Hubbell. The composition of the woo proceedings [ 5 ] includes a comprehensive recapitulation of the development of the art in the US anterior to 1919, based on evidence presented to the Court. dissociable plugs had been available for more than a ten anterior to Hubbell ‘s 1904 design .

NEMA [edit ]

In 1926, the National Electrical Manufacturers Association ( NEMA ) was founded by the amalgamation of the Electric Power Club and the Associated Manufacturers of Electrical Supplies, [ 6 ] and represented manufacture companies of the electric segment in a national floor. NEMA provided a forum between companies for reaching standardization, but it was not until the 1940s that NEMA started to publish standards on receptacles and plugs, way later than UK, [ 7 ] France and Germany. [ 8 ] Since NEMA was a forum between manufacturers and not an governmental body, any decision had to be thoroughly discussed and agreed upon by its members, which well slowed the calibration process .

terminology [edit ]

"Row and column table of NEMA receptacles." NEMA receptacles, with their common US uses listed ( in purple text ) NEMA connectors are named following an alphanumeric code consisting of : prefix “ L ” ( locking types ), numerals, a hyphenate, numerals, suffix “ R ” or “ P ” for “ receptacle ” or “ hack ”. There are two basic classifications of NEMA connectors : straight-blade and locking. The metallic element conductive blades are often informally called “ prongs ” ( as in “ 3-prong plug ” ). Numbers prefixed by ‘ L ‘ are curved-blade, twist-locking connectors. Twist-locking types are used for heavy industrial and commercial equipment, where increased protection against accidental disconnection is required. The numerals preceding the hyphenate encode the number of poles ( current-carrying terminals ) and wires connected to it, the electric potential, and single- or three-phase power. A connection with ground terminal is described as having more wires than poles, e.g. two-pole, three-wire ; or four-pole, five-wire ; etc. A non-grounding device may be two-pole, two-wire ; three-pole, three-wire ; etc. The numerals following the hyphen is the stream rat of the device in amperes. This number is followed by the letter ‘ R ‘ to indicate a receptacle or ‘ P ‘ to indicate a plug. As an case, the 5-15R is the common 125 V two-pole, three-wire receptacle rated for 15 A. The L5-15R, while sharing the same electrical rating, is a locking design that is not physically compatible with the straight-blade 5-15 design. The 5-30R has the same two-pole, three-wire shape and 125 V rating, but is rated for 30 A. Although there are several non-grounding device types in the NEMA standards, only three of them are in far-flung use today. These are the two-pole 1-15, calm in use in millions of buildings built before the 1960s, and the three-pole 10-30 and 10-50. early types of NEMA connectors that do not follow this terminology include : the ML series ( alleged “ Midget Locking ” connectors named for their diminutive size ), TT ( for connecting travel trailers and early recreational vehicles to external power sources ), SS serial ( “ ship-to-shore ” connectors for connecting boats to shore office ) and the FSL series ( used in military and aircraft applications ). The small trap near the end of the ability ( non-ground ) blades of some NEMA plugs is used for convenience in manufacture ; if award, it must be of intend diameter and position. [ 2 ] Small specialized padlocks are available to fit these holes, allowing “ lockout “ of hazardous equipment, by physically preventing interpolation of interlock plugs into a might receptacle. Since at least 1949, numerous receptacle devices have besides been invented to use these holes to hold the prongs inside the receptacle slots, using a match latch or locking mechanism. [ 9 ] The blades of a NEMA connection are identified within the dimensional standard as follows : ‘ G ‘ identifies the ground conductor, ‘ W ‘ identifies the ( grounded ) neutral conductor, and ‘ X ‘, ‘ Y ‘, and ‘ Z ‘ are the “ hot ” line conductors. Single-phase connectors have merely a single concluding identified as ‘ X ‘ or two terminals, ‘ X ‘ and ‘ Y ‘. Three-phase connectors will use ‘ X ‘, ‘ Y ‘ and ‘ Z ‘. [ 2 ] criticism has been aimed [ by whom? ] at the plan leaving a col with expose prongs. This safety flaw has been exploited by a January 2020 Internet phenomenon known as the Outlet challenge, where conductive materials, normally coins or wallpaper clips were dropped into the gap, causing electric sparks, which once led to a build emptying in Westford Academy. [ 10 ] [ 11 ] [ 12 ]

NEMA classes
Pole configuration 120/208/240 V service 277/480 V service 347/600 V service 240/415 V service
Voltage Grounded Voltage Grounded Voltage Grounded Voltage Grounded
no yes no yes no yes no yes
hot-neutral 120 V 1; ML1 5; TT;
SS1 ; ML2
277 V 3 7 347 V 24 240 V 25
hot-hot 240 V (split-phase)
208 V (wye)
2 6 480 V 8 600 V 4 9 415 V
hot-hot-neutral 120/240 V (split-
phase )
120/208 V ( y )
277/480 V 347/600 V 240/415 V
hot-hot-hot 240 V (delta)
208 V (wye)
11 15 480 V 12 16 600 V 13 17 415 V
hot-hot-hot-neutral 120/208 V 18 21 277/480 V 19 22 347/600 V 20 23 240/415 V 26

Non-locking connectors [edit ]

NEMA non-locking connectors all use blades of respective flatcar and fold shapes ( except for the circle pins used on grounding connectors ). The plugs can be detached from the receptacles by pulling back on the punch body. These connection families have been designed so that connectors of differing types can not be by chance intermated. NEMA wall receptacles can be found installed in any orientation. Neither NEMA nor the US National Electrical Code nor the canadian Electrical Code specify a favored orientation, but the National Electrical Contractors Association ‘s National Electrical Installation Standards ( NECA 130-2010 ) specify that the favored location of the ground is on circus tent. When the grind blade of a receptacle is on the bottom, the neutral blade is on the amphetamine left and the hot blade is on the upper correctly. All descriptions below assume this orientation ( i.e. clockwise order is grind, neutral, hot for 120 V receptacle versions ; and counter-clockwise for punch versions ) .

NEMA 1 [edit ]

This “ 2-prong ” blueprint, with two flat parallel non-coplanar blades and slots, is used in most of North America and on the east coast of South America on lamps ; consumer electronics such as clocks, radios, and battery chargers ; and other double-insulated modest appliances that do not require prime ( earthing ). All NEMA 1 devices are two-wire non-grounding devices ( hot-neutral ) rated for 125 V utmost. 1-15P plugs have two latitude compressed blades, 1⁄4 column inch ( 6.4 millimeter ) wide, 0.06 inches ( 1.5 millimeter ) slurred, 5⁄8–23⁄32 inch ( 15.9–18.3 millimeter ) long, and spaced 1⁄2 inch ( 12.7 millimeter ) apart. 1-15R receptacles have been prohibited in newfangled construction in the United States and Canada since 1962, but remain in many older buildings, and this disused invention is still available for compensate use only. Since January 1, 1974, all new exponent outlets are required to have a land connection, using grounded receptacles ( typically 5-15R or 5-20R ) that accept both ground and non-grounded plugs. [ 13 ] Replacement of disused NEMA 1 receptacles requires either rewiring with an extra land conductor for a NEMA 5 receptacle, or a NEMA 5 receptacle complete with a ground demerit circuit interrupter for two-wire non-grounded configurations ( when a land conductor is not available ). Ungrounded NEMA 1 plugs are still popularly used by manufacturers of small appliances and electronic devices because of the design ‘s low cost and compact size, and they are up compatible with modern grounded NEMA 5 receptacles. Standards license ungrounded plugs where the appliance does not require grounding due to low risk of escape stream, such as on double-insulated devices. In older spark plug designs both blades were the lapp width, so the plug could be inserted into the receptacle either way around. many plugs manufactured since 1948 are polarized ; the impersonal blade is 5⁄16 in or 7.9 mm wide, 1⁄16 in or 1.6 mm wider than the line blade, so the fireplug can be inserted only one way. Polarized 1-15P plugs will not fit into unpolarized receptacles, which possess entirely minute slots. Polarized 1-15P plugs will fit 5-15R prime receptacles, which have the lapp wide slot for the neutral blade. Some devices that do not distinguish between achromatic and pipeline, such as internally detached AC adapters, are even produced with unpolarized pin down blades. Cheater ballyhoo adapters allow a “ 3-prong ” grounded 5-15P plug to be mated to a non-grounded 1-15R receptacle. The adapters include a spade lugsail to allow connecting to ground, often via the cover screw used to attach the release faceplate. These adapters are illegal in some jurisdictions, in particular throughout Canada. [ 14 ] There are some disused 1-15R or 1-20R ( 120 V, 15 or 20 A ) receptacles which are mechanically able to accept 1-15P ( 120 V ), 1-20P ( 120 V ), 2-15P ( 240 V ), or 2-20P ( 240 V ) plug. These receptacles are typically found in older residential buildings and are not allowed to be installed under current NEC codes. In addition to the miss of ground, these disused receptacles could allow a connect device to overheat and create a fire gamble if a device designed for the wrong electric potential is connected. These debatable outlets are easily identifiable ascribable to their lack of establish, along with both openings on the receptacle face being a sidelong “ T ” shaped opening that appear to be mirrored on the upright center field line of the face. ascribable to the potential danger of a electric potential mismatch, whenever potential these receptacles should be replaced. Depending on local code, successor with a “ compensate ” approved non-grounded receptacle may be sufficient. The japanese plug and socket with minute insulating faces appear and employment physically identical to NEMA 1-15, and such non-grounded receptacles are still common in Japan ( though grounded 5-15R and 5-20R receptacles are lento becoming more common ). The japanese system incorporates stricter dimensional requirements for the plug housing, unlike marking requirements, and mandate examination and approval by METI or JIS. [ 15 ] NEMA standards exist for 1-15P, 1-20P and 1-30P plugs, and the 1-15R receptacle. There are no 1-20R and 1-30R receptacles, because 1-20P and 1-30P can mate with a corresponding NEMA 5 receptacle .

NEMA 2 [edit ]

All NEMA 2 devices are two-wire non-grounding devices ( hot-hot ) rated for 250 V maximum. Although standards exist for 2-15, 2-20 and 2-30, this series is disused, and only Hubbell still manufactures 2-20 devices ( for rectify purposes ). [ 16 ]

NEMA 3 [edit ]

This serial of devices is specified for 277-volt, two-wire, non-grounding devices. According to NEMA, this is “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured. [ citation needed ]

NEMA 4 [edit ]

This serial of devices is specified for 600-volt, two-wire, non-grounding devices. identically to the NEMA 3 series, this is “ reserved for future configurations ” and no design for this series exist and no devices have been manufactured. [ citation needed ]

NEMA 5 [edit ]

NEMA 5-15P plug and NEMA 5-15R receptacle ( different scales, blade space is 0.5 inches ( 12.7 millimeter ) for both. ) Each receptacle besides accepts an ungrounded plug, whether polarized or unpolarized typical 5-15R residential receptacle 5-20R T-slot receptacle mounted with the hole for the ground pin at the top. The achromatic connection is the wider t-shaped slot on the mighty. All NEMA 5 devices are three-wire ground devices ( hot–neutral–ground ) rated for 125 V utmost, with the 5-15, 5-20 and 5-30 being ground versions of the 1-15, 1-20 and 1-30, respectively. The addition is a 3⁄16-inch ( 4.8 millimeter ) diameter round or u-shaped ground pin, 1⁄8 in ( 3.2 millimeter ) longer than the power blades ( so the device is grounded before the world power is connected ) and located from them by 1⁄4 in ( 6.4 millimeter ) edge-to-edge or 15⁄32 in ( 11.9 millimeter ) center-to-center. Compared to the 5-15P plug, the 5-20P plug has the neutral sword rotated 90° and shifted so its inner border is approximately 1⁄2 in ( 12.7 millimeter ) from the hot blade. The 5-20R receptacle has a t-shaped impersonal hole, to accept both 5-15P and 5-20P plugs. An satisfactory alternate translation of the 5-20R receptacle has a orthogonal slot that will only accept 5-20P plugs. The 5-30 and 5-50 are physically larger, with 1 in ( 25.4 millimeter ) between power pins ; 5-30 besides has an l-shaped impersonal blade. [ 17 ] These larger sizes are rare, as twist-locking plugs are by and large used for high-current applications. The neutral blade on 5-15P plugs is not always wider than the line blade, since the labor pin enforces mutual opposition. The Electrical Safety Foundation International has stated : “ never remove the ground pin ( the third gear prong ) to make a three-prong plug fit a two-prong release ”. [ 18 ] In accession to the dangers of breaking a ground connection, removing the ground pivot to make it fit a 1-15R receptacle or elongation cord, may result in the live–neutral mutual opposition being lost. The 5-15R and 5-20R are by far the most common electric receptacle in North America in buildings built since the mid-twentieth century. It is normally installed in a duplex house configuration ; two receptacles may contribution a common circuit or may each be wired individually, sometimes to a switch. In 46 of the 50 United States [ 19 ] and all of Canada, tamper-resistant receptacles are required in new residential structure as of November 2013. These prevent contact by objects like keys or newspaper clips inserted into the socket. [ 20 ] This is accomplished by an mesh mechanism that requires hot and neutral blades inserted simultaneously to release the little doors blocking the slots. The grounding slot is not blocked by a door. In stage lighting for film and theater, this connection is sometimes colloquially known as PBG ( Parallel Blade with Ground ), U-ground, Edison or Hubbell, the name of a common manufacturer. [ 21 ] ( The name “ Hubbell ” can be confusing as several different connectors share this name depending on the company, diligence, and use. ) In the motion photograph and television receiver production industries, an elongation cord that uses this type of connection ( normally with 12 AWG or 10 AWG telegram ) [ 22 ] is called a “ stinger ”. [ citation needed ] Generally, lighting technicians use these propagation cords to deliver office to lights rated at 2,000 watts or less. [ 23 ] internationally, the NEMA 5-15P plug and NEMA 5-15R receptacle are the basis for the International Electrotechnical Commission ‘s IEC 60906-2 standard IEC system of plugs and sockets-outlets for household and similar purposes – Part 2: Plugs and socket-outlets 15 A 125 V a.c. and 20 A 125 V a.c. [ 24 ]

NEMA 6 [edit ]

All NEMA 6 devices are three-wire establish devices ( hot-hot-ground ) used for 208 and 240 V circuits and rated for 250 V maximal, with the 6-15, 6-20 and 6-30 being grounding versions of the 2-15, 2-20 and 2-30, respectively. The 6-15 resembles the 5-15, but with collinear horizontal pins, spaced 23⁄32 in ( 18.3 millimeter ) center-to-center. The 20 A plug has a blade rotated 90° ( opposite blade from what would be the “ line ” blade on a 2-15 or 5-15 plug. This prevents accidental interpolation of plugs into outlets that use different voltages ), and the 6-20R receptacle has a t-shaped hole to accept both 6-15P and 6-20P plugs ( similar to the 5-20R receptacle accepting 5-15P and 5-20P plugs ). 6-15R and 6-20R receptacles are normally manufactured on the lapp assembly line as “ Industrial ” or “ commercial ” grade 5-15R and 5-20R receptacles, with all 4 receptacles sharing the same “ treble rub ” T contacts behind the varying faceplates. The faceplate bonded onto the receptacle determines the final examination configuration of the receptacle. [ citation needed ] The 30 A plug and receptacle look similar to the 15 A one but larger. The higher-current versions are rare, with twist-locking plugs such as L6-30 or direct cable more common. by and large 6-series non-locking plugs are used for such appliances as large room air travel conditioners, commercial kitchen equipment, and the occasional dwelling bow welder. Single-phase 6-50 is normally used on farms for silo unloaders, and is used with a 6-gauge flexible exponent cord up to 200 foot ( 61 molarity ) long. The 6-50 is besides used on arch welders. [ 25 ] Some manufacturers of electric vehicle charging stations equip their 30-40 A Level 2 EVSEs with a 6-50 plug on a short cord, though it is becoming less common, with manufacturers now favoring the more common 14-50 hack. [ citation needed ] NEMA 6 devices, while specified as 250 V, may be used for either 208 or 240 V circuits, broadly depending on whether the building has a three-phase or split-phase exponent issue, respectively. The NEMA 6-20R or 6-30R found in many hotel and motel rooms is typically supplied with either split-phase or two phases of three-phase 208 V .

NEMA 7 [edit ]

NEMA 7 devices are 2-pole and prime connectors rated at 277 V. The 15 A 7-15 plug has the crowsfoot current carrying pins of the Type I plug, but with a u-shaped earth pin. The 7-20 translation has an enlarged line/hot fall. 7-30 is a larger diameter connection, with an l-shaped neutral, while the 7-50 has an hypertrophied neutral fall, compared with the hot .

NEMA 8 [edit ]

NEMA 8 devices are specified for three-wire, two-pole, ground devices for 480 volts. According to NEMA, this is “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured .

NEMA 9 [edit ]

NEMA 9 devices are specified for three-wire, two-pole, ground devices for 600 volts. According to NEMA, this is “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured .

NEMA 10 [edit ]

The now- deprecate NEMA 10-30 has a achromatic trap ( at top of photograph ), but does not have a dedicated safety grounding peg. NEMA 10 connectors are a now deprecated type that had once been popular in the United States for use with high-octane electric clothes dryers, kitchen ranges, and other high-octane equipment. NEMA 14-30R and -50R connectors have by and large replaced NEMA 10 equipment for these applications. NEMA 10s are classified as 125/250 V non-grounding ( hot-hot-neutral ), and were designed to be used in a manner that indirectly grounds the appliance skeletal system to the inert, which was common before the prerequisite of a separate condom grind was incorporated in the National Electrical Code. As normally used, 10-30 and 10-50 plugs required the frame of the appliance to be indirectly grounded via a strap connecting to the impersonal blade. condom operation relied on the impersonal conductor in turn being connected to system ground at the circuit breaker or blend box. If the impersonal conductor were to break, disconnect, or develop high electric resistance, the appliance ensnare could become stimulate to dangerous voltages. Modern practice is to require a freestanding guard grounding conductor whose only determination is to divert dangerous voltages, and which does not carry significant current during normal operation. Relying on the neutral conductor was a legal ground method for electric ranges and clothes dryers, under the National Electrical Code from the 1947 to the 1993 editions ( banned in 1996 edition ). Since north american english dryers and ranges have certain components ( timers, lights, fans, etc. ) that run on 120 V, this means that the neutral wire indirectly used for grounding would besides carry stream, even under non-fault conditions. Although this is adverse to modern grounding practice, such “ grandfathered “ installations remain coarse in older homes in the United States. [ 26 ]

NEMA 11 [edit ]

NEMA 11 series devices are three-wire, three-pole, non-grounding devices for 3 phase 250 volt equipment and designs for 20 adenosine monophosphate ( 11-20 ), 30 adenosine monophosphate ( 11-30 ), and 50 adenosine monophosphate ( 11-50 ) parts are specified by NEMA. [ citation needed ]

NEMA 12 [edit ]

NEMA 12 serial devices are three-wire, three-pole, non-grounding devices for 3 phase, 480 volt equipment. According to NEMA, this is “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured .

NEMA 13 [edit ]

NEMA 13 serial devices are three-wire, three-pole, non-grounding devices for 3 phase, 600 volt equipment. According to NEMA, this is “ reserved for future configurations ”, so no invention for this serial exist and no devices have been manufactured .

NEMA 14 [edit ]

The NEMA 14 devices are four-wire ground devices ( hot-hot-neutral-ground ) available in ratings from 15 to 60 A. The voltage military rank is 250 V. Of the straight-blade NEMA 14 devices, only the 14-30 and 14-50 are in common use. The 14-30 is used for electric clothes dryers, the 14-50 is used for electric cook ranges, and either may besides be used for home charge of electric vehicles. The NEMA 14 connectors are basically the replacements for the older NEMA 10 connectors described above, but with the addition of a dedicate anchor connection. All NEMA 14 devices offer two hots, a neutral, and a ground, allowing for both 120 and 240 V when supplied by split-phase power, or 120 and 208 V if the issue is three-phase. The 14-30 has a fink of 30 A, and an l-shaped inert blade. The 14-50 has a rate of 50 A, and a true impersonal blade sized thus that it does not mate with 14-30 connectors. NEMA 14-50 devices are frequently found in RV parks, since they are used for “ shore power “ connections of larger amateur vehicles. besides, it was once common to connect mobile homes to utility exponent via a 14-50 device. Newer applications include Tesla ‘s Mobile Connector for vehicle charge, which once recommended the initiation of a 14-50 receptacle for home use. [ 27 ]

NEMA 15 [edit ]

NEMA 15 are three-pole and land connectors rated for 208 V. Intended for delta three-phase circuits with earth and no neutral. The straight blades all carry one of the three phases. [ citation needed ]

NEMA 20 [edit ]

NEMA 20 series devices are specified for 347/600Y three-pole, four-wire, non-grounding devices. According to NEMA, this is “ reserved for future configurations ”, so no design for this serial exist and no devices have been manufactured. [ citation needed ]

NEMA 21 [edit ]

NEMA 21 series devices are specified for three-pole plus inert, five-wire ground devices for 3 phase 120/208Y supplies. According to NEMA, NEMA 21 straight-blade devices are “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured. There are however NEMA L21 series locking devices for 20 and 30 ampere devices specified and available for these applications. [ citation needed ]

NEMA 22 [edit ]

NEMA 22 serial devices are specified for three-pole plus neutral, five-wire ground devices for 3 phase 277/480Y supplies. According to NEMA, NEMA 22 straight-blade devices are “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured. There are however NEMA L22 series locking devices for 20 and 30 adenosine monophosphate devices specified and available for these applications. [ citation needed ]

NEMA 23 [edit ]

NEMA 23 series devices are specified for three-pole plus achromatic, five-wire ground devices for 3 phase 347/600Y supplies. According to NEMA, NEMA 23 straight-blade devices are “ reserved for future configurations ”, so no design for this series exist and no devices have been manufactured. There are however NEMA L23 series locking devices for 20 and 30 ampere devices specified and available for these applications. [ citation needed ]

NEMA TT-30 [edit ]

NEMA TT-30 spark plug and receptacle. ( The center hole on the receptacle is not a contact. ) The NEMA TT-30 ( TT stands for Travel Trailer ) connection is a 120 V 30 A recreational vehicle standard ( hot-neutral-ground ), besides known as RV 30. The TT-30R receptacle is normally available in closely all RV parks in the United States and Canada, and all but the largest recreational vehicle manufactured since the 1970s use this plug to connect to power feeds. The appearance of this plug is sometimes confused with a NEMA 10 connection, rated for 240 V, but the NEMA TT-30 is a 120 V device. The hot and neutral blades are angled at 45° from upright and 90° to each other, unlike NEMA 10 devices ( where the angles are 30° and 60° respectively ), besides the plug is slenderly smaller than a NEMA 10 and larger than ordinary 5-15P plugs. The footing pin is round, like those on straight-blade NEMA ground devices. Referring to the mental picture, the orientation is the same as the NEMA 5 plug and receptacle, with the achromatic sword on the lower right. Adapters are available with the TT-30P spark plug on one side and a 5-15R or 5-20R receptacle on the early side. When a power prey cord is detachable from an RV, an L5-30P is normally used on the RV end of the cord .

Twist-locking connectors [edit ]

Twist-locking connectors were foremost invented by Harvey Hubbell III in 1938 and “ Twist-Lock ” remains a record trademark of Hubbell Incorporated, [ 28 ] [ 29 ] although the terminus is used generically to refer to NEMA locking connectors manufactured by any caller. Locking connectors use curved blades. once pushed into the receptacle, the plug is twisted and its now-rotated blades latch into the receptacle. To unlatch the chew, the rotation is reversed. The locking couple makes for a more dependable connection in commercial and industrial settings, where oscillation or attendant impact could disconnect a non-locking connection. Locking connectors come in a variety show of standardized configurations that follow the same cosmopolitan naming system except that the designations include an “ L ” for “ locking ”. Locking connectors are designed so that unlike voltages and stream ratings can not be by chance intermated. [ 30 ] Many specific types exist ; entirely a few are listed below. early types include limited purpose connectors for boats, 400 Hz circuits such as used for aircraft, and direct-current applications. One apparent disadvantage of twist-lock connectors is that in the event that the cable is by chance pulled besides hard, rather than the spark plug falling out of the receptacle, exposed conductors may come out of the chew, causing dangerous shorts or shock hazards if the circuit is live. This is resolved in most cases by the connection having a robust integral strain easing .

milliliter [edit ]

ML-series “ Midget Locking ” connectors are for 15 A applications where a larger lock connection would not fit. [ 31 ]

  • ML-1 connectors are two-pole, no ground, rated for 125 V.
  • ML-2 connectors are two-pole with ground, rated for 125 V.
  • ML-3 connectors are for three-pole no ground (hot-neutral-hot) rated for 125/250 V.

sulfur [edit ]

SS-series “ Ship-to-shore ” connectors are for 50 A marine shore-power applications .

  • SS1-50 connectors are two-pole with ground, rated for 125 V.
  • SS2-50 connectors are three-pole with ground (hot-neutral-hot) rated for 125/250 V.

NEMA L1 [edit ]

NEMA L1 series devices are single-pole plus achromatic, two-wire, non-grounding devices for 125 volts single phase. Designs and devices for 15 ampere devices ( L1-15 ) exist .

NEMA L2 [edit ]

NEMA L2 series devices are two-pole, two-wire, non-grounding devices for 250 volts single-phase. Designs and devices for 20 ampere devices ( L2-20 ) exist .

NEMA L3 and L4 [edit ]

These devices would have been for 277 and 600 volt two-pole, two-wire non-grounding devices exchangeable to the straight-blade NEMA 3 and 4 families, but were never specified by NEMA .

NEMA L5 [edit ]

NEMA L5 connectors are a series of two-pole and ground locking connectors rated for 125 V. L5-30R receptacles are common at marinas that provide office to docked boats. They are besides found on some RVs for connecting to shore power. RVs in the US are equipped for 120 V 30 A or 240 V 50 A service, and use a cord to connect to a receptacle at the campsite, normally on a ability base with one or more receptacles providing 120 V 30 A ( TT30R ), 240 V 50 A ( 14-50R ), or 120 V 15/20 A ( 5-20R ) service. Locking receptacles appropriate for the electric potential and current are used on the RV goal of the cord, along with non-locking plugs on the conclusion connect to the base .

NEMA L6 [edit ]

NEMA L6 connectors are rated for a utmost of 250 volts. They are intended for two-pole, three telegram, line-line-earth ( or hot-hot-ground ) circuits with a nominal add electric potential of 208 or 240 volts, depending on phase shape. The L6 connection does not provide a neutral connection. L6-20 connectors provide a utmost of 20 amps and are normally found in power distribution units ( PDUs ) used in the information technology sector. Most often, these connectors can be found in server rooms and datum centers where the connectors are used to power equipment such as servers, backing systems and UPS units. L6-30 connectors provide a maximum of 30 amps and tend to be used in heavy-industry sectors. For example, welders and other fabrication machinery where industrial equipment or bombastic might tools are commonplace .

NEMA L7 [edit ]

NEMA L7 are two-pole and grate connectors rated for 277 V. Typically, these connectors are found in commercial or industrial lighting circuits, particularly where metallic element halide lamps are park .

NEMA L8 [edit ]

NEMA L8 are two-pole and ground connectors rated for 480 V. Intended for three-wire hot-hot-ground circuits .

NEMA L9 [edit ]

NEMA L9 are two-pole and footing connectors rated for 600 V. Intended for three-wire hot-hot-ground circuits .

NEMA L10 [edit ]

NEMA L10 series devices are two-pole plus impersonal, three-wire, non-grounding devices for 125/250 volts single-phase. These are deprecated due to the miss of grounding but L10-20 and L10-30 devices are specified by NEMA and are commercially available .

NEMA L11 [edit ]

NEMA L11 series devices are three-pole, three-wire, non-grounding devices for three-phase 250 volt devices. Designs exist for 15 adenosine monophosphate ( L11-15 ), 20 ampere ( L11-20 ), and 30 adenosine monophosphate ( L11-30 ) devices, and L11-20 and L11-30 devices were commercially available from at least one manufacturer ( Bryant Electric ) .

NEMA L12 [edit ]

NEMA L12 series devices are three-pole, three-wire, non-grounding devices for three-phase 480 volt devices. Designs exist for 20 ampere ( L12-20 ), and 30 adenosine monophosphate ( L12-30 ) devices, and L12-20 and L12-30 devices were commercially available from at least one manufacturer ( Bryant Electric ) .

NEMA L13 [edit ]

NEMA L13 series devices are three-pole, three-wire, non-grounding devices for three-phase 600 volt devices. Designs exist for 30 adenosine monophosphate ( L13-30 ) devices and L13-30 devices were commercially available from at least one manufacturer ( Bryant Electric ) .

NEMA L14 [edit ]

NEMA L14 are three-pole and grind connectors rated for 125/250 V. Intended for three-pole, four-wire hot-hot-neutral-ground circuits with a nominal provide voltages of 240 or 208 V hot-to-hot and 120 V hot-to-neutral. These connectors are common on family accompaniment generators, and on racks of power amplifiers in large audio systems .

NEMA L15 [edit ]

NEMA L15 are three-pole and ground connectors rated for 250 V. Intended for three-phase circuits .

NEMA L16 [edit ]

NEMA L16 are three-pole and ground connectors rated for 480 V. Intended for three-phase circuits .

NEMA L17 [edit ]

NEMA L17 are three-pole and ground connectors rated for 600 V. Intended for three-phase circuits .

NEMA L18 [edit ]

NEMA L18 are four-pole no grate connectors rated for 120/208 V. Intended for y three-phase circuits .

NEMA L19 [edit ]

NEMA L19 series devices are three-pole, four-wire, non-grounding devices for three-phase 277/480 volt devices. Designs exist for 20 adenosine monophosphate ( L19-20 ), and 30 adenosine monophosphate ( L19-30 ) devices, and L19-20 and L19-30 devices were commercially available from at least one manufacturer ( Bryant Electric ) .

NEMA L20 [edit ]

NEMA L20 series devices are three-pole, four-wire, non-grounding devices for three-phase 347/600 volt devices. Designs exist for 20 ampere ( L12-20 ), and 30 ampere ( L20-30 ) devices, and L20-20 and L20-30 devices were commercially available from at least one manufacturer ( Bryant Electric ) .

NEMA L21 [edit ]

L21-30 plug and receptacle NEMA L21 are four-pole and ground connectors rated for 120/208 V. Intended for y three-phase circuits with both impersonal and prime. The peg in the middle is land, and the blade with a right angle on the check is achromatic. These connectors are common in hot event power distribution. many event production companies use power distributors with camlock connectors for feeder cable, and 12 or more L21-30 connectors which can each be broken out to three individual 120 V circuits via the use of a stringer box. [ citation needed ]

NEMA L22 [edit ]

NEMA L22 are four-pole and labor connectors rated for 277/480 V. Intended for y three-phase circuits with both neutral and land. The pin in the middle is land, and the blade with a right angle on the yellow journalism is achromatic .

NEMA L23 [edit ]

NEMA L23 are four-pole and ground connectors rated for 347/600 V. Intended for y three-phase circuits with both neutral and ground. The pin in the center is ground, and the blade with a correct slant on the tab key is neutral .

Additional condom features [edit ]



 in (16 mm) drywall instead of



 in (13 mm), or by slightly-misplaced device box housings. A north american NEMA-5 receptacle halfway through a corrective re-installation. The fluorescent green spacers, which securely attach the receptacle to the metallic sub-structure, are made necessity by usingin ( 16 millimeter ) wallboard rather ofin ( 13 millimeter ), or by slightly-misplaced device box housings. Over fourth dimension, electrical codes in the US and Canada began to require extra base hit features in the basic NEMA 5-15R and 5-20R configurations to address specific electric shock luck concerns. The guard features listed below are not mutually single ; for case, tamper-resistant GFCI receptacles are available. [ 32 ]

ground blame circuit interrupter ( GFCI ) receptacles [edit ]

Tamper-resistant GFCI duplex receptacle type 5-20RA, which can take 5-15 and 5-20 ground plugs and 1-15 ungrounded plugs These versions of the 5-15R or 5-20R receptacle are residual-current devices, and have “ Test ” and “ Reset ” buttons ( and sometimes an index unaccented which may be normally on or normally off per the seller ‘s design ). In the US and Canada, GFCI protection is required for receptacles in many potentially wet locations, including outside outlets, bathrooms, and some places in kitchens, basements, and crawl spaces. This is an expedient way to provide that protection at the receptacle itself. [ 33 ] These safety devices work by comparing the currents flowing in the exist and neutral conductors, and disconnect the circuit if their remainder exceeds 4 to 6 milliamperes. Installing a single receptacle is much cheaper or more convenient than providing this GFCI protection at the circuit breaker. In addition, a trip GFCI receptacle may be more well noticed and reset, as compared to a trip GFCI located in a distant circuit surf dialog box far from the point of custom. Like most current interrupt devices, a GFCI receptacle can optionally be wired to feed extra “ downriver ” outlets ; correctly installing one GFCI receptacle in a circuit can protect all the plugs, lights, switches, and wiring which receive world power from it. This allows for cost-efficient retrofits on older installations where branch circuits were frequently daisy-chain between wet and dry locations. A GFCI receptacle may be installed indoors where it is sheltered from damp and corrosion, while still protecting an outdoors receptacle wire downriver. GFCIs are besides recommended for ability tool outlets and any locations where children might insert conductive objects into the receptacles, although this guard measure does not substitute for extra requirements for tamper-resistant receptacles. [ 33 ]

Tamper-resistant receptacles [edit ]

Starting with the 2008 National Electrical Code [ 34 ] and the 2009 canadian Electrical Code, [ 35 ] listed tamper-resistant receptacles that address electric shock hazards to children must now be installed in about all areas of fresh or renovate dwellings. According to statistics cited by the NFPA, the code change adds lone $ 40 to the cost of building an modal, 75-receptacle home in the US. [ citation needed ] This safety measure reduces shock hazards to a child that attempts to insert a single conductive aim into the receptacle. Inserting a normal, two-blade electric plug applies coincident atmospheric pressure on both sides of the receptacle to open an internal, spring-loaded shutter, but a alien object fails to do so and therefore can not make contact with the live electric contacts. [ 36 ] however, the device can still be defeated by inserting two objects simultaneously. Despite its weaknesses, the tamper-resistant receptacle is superior to protective fictile release caps which must be individually installed on each receptacle ( and are a choking hazard when removed ), and to sliding covers that children easily learn to defeat. [ 34 ]

AFCI receptacles [edit ]

The National Electrical Code has been updated for 2014 to address the use of Outlet Branch Circuit ( OBC ) Arc Fault Circuit Interrupter ( AFCI ) receptacles as an alternative to traditional circuit breakers when used for modifications, extensions, refilling receptacles, or in new construction. AFCI receptacles reduce the dangers associated with potentially-hazardous arcing conditions ( parallel discharge and serial bow ), by interrupting power to arcing devices ( e.g. a damaged appliance cord ) that might otherwise not draw enough current to slip the primary lap protection device. AFCI protective covering is mandated by the 2014 Code in residential family rooms, dining rooms, living rooms, kitchens, parlors, libraries, dens, bedrooms, laundry rooms, sunrooms, refreshment rooms, closets, hallways or similar rooms. [ citation needed ] It is besides required in dormitory units. AFCI receptacles look alike to GFCI receptacles in that they have a “ screen ” and “ Reset ” button on the confront of the device for localize test. This saves a homeowner a stumble to the surf panel, should the device slip. Unlike AFCI breakers, AFCI receptacles can be used on any wire organization, careless of the dialog box. [ citation needed ] When installed as the first gear receptacle on a arm lap, AFCI receptacles can provide series discharge protection for the stallion outgrowth circuit. They besides provide parallel bow protection for the arm racing circuit downriver of the AFCI receptacle .

Surge protective receptacles [edit ]

Surge protective devices are designed to reduce the random energy surges of voltage transients and electric randomness on the power supply line, which can damage sensible electronics such as TVs, computers, and bright appliances. They are available for 120 V, 15/20 A applications, in different form factors such as rush protective receptacles in one, duplex house, four-in-one, and six receptacle configurations, angstrom well as surge-protective ability strips. These devices provide point-of-use protection and are the last line of defense in a whole-house surge protection network .

Weather-resistant receptacles [edit ]

Weather-resistant ( WR ) receptacles are made with ultraviolet-resistant isolate materials having excellent cold-temperature affect resistance to withstand longterm photograph to weather and maltreatment. metallic components are required to be immune to corrosion. Mandated by the 2008 National Electrical Code in outdoor muffle or wet locations, WR receptacles are required in patio, deck, and pond areas. [ citation needed ] They are available in a variety of variations, including GFCI and tamper-resistant. For added protection, WR receptacles should be shielded by “ Extra-Duty While In-Use ” or “ Weather-Resistant ” covers. [ citation needed ] These covers are ruggedly constructed to keep out moisture ( either dripping or condensing ), dust, debris, and insects, while providing easy entree to receptacles to allow their use with office tools, trimmers, sprinkler systems, and pumps .

Leak-current detection and break ( LCDI ) cordsets [edit ]

Damaged office cords of portable breeze conditioners have caused many electric fires, and about 350 deaths per year. [ citation needed ] To combat this, the 2017 NEC [ 37 ] requires each portable atmosphere conditioner sold in the United States to have either a escape current detector interrupter ( LCDI ) or a ground-fault racing circuit interrupter ( GFCI ) protective device built into its ability cord. The device can be integral with the baron plug, or a divide module within 12 inches of the fireplug. The protection device is equipped with “ Test ” and “ Reset ” buttons on the house. An LCDI cord has a fine telegram engage around the conductors, and circuitry to detect current leak from the conductors to the mesh, which would happen if the cord were damaged or frayed. The plugs are normal NEMA 5-15, 5-20, 6-15, 6-20, or 6-30 plugs, depending on the air conditioner invention, and are typically molded-on designs .

color code [edit ]

The color of a device neither identifies its electric potential class nor power organization. Because the colors are not specified by NEMA standards, the purpose of color-coding a receptacle may be set by the build owner, who may select embrown, ivory, white, almond, grey, or black receptacles in the 5-15 configuration to blend with the interior decoration of a room.

however, although colors are not standardized by NEMA, some industries utilize colors for certain applications, following de facto standards :

  • A receptacle with a green dot is a so-called “hospital grade” device; The primary reason to use a hospital-grade receptacle at a patient bed location is to ensure that a receptacle with a greater contact tension is provided to minimize possibilities that an attachment plug supplying medical or life support equipment may be disconnected because the attachment plug slipped out of the receptacle. Also such devices are tested to survive harder use while limiting electrical leakage, compared to wiring devices intended for residential or commercial purposes.
  • Per UL Standard ANSI/UL 498, a receptacle (any color) with an orange triangle, is an isolated ground (IG) device, where the grounding pin of the receptacle is connected to ground independently of the frame of the receptacle and wiring outlet box. This is also a requirement of the National Electrical Code (NFPA 70), Article 406. While neither UL nor the CSA require the face of the receptacle to be a specific color, most IG receptacles are orange.[38]
  • A blue receptacle may indicate built-in surge suppressors.
  • A red receptacle may indicate a special-service outlet such as one connected to an emergency standby power source. The Canadian Electrical Code requires that “essential” receptacles in hospitals, connected to emergency power systems, must be red.[39]
  • At least one manufacturer makes a yellow receptacle, which identifies it as corrosion-resistant.

Break-away tab [edit ]

Most duplex house receptacles have metal tabs connecting the lead and bottom receptacles. These tabs can be broken off to allow the top and penetrate receptacles to be wired onto separate circuits. [ 40 ] This may allow for one switch over receptacle for a lamp, or for two disjoined issue circuits when arduous loads are anticipated. Two arm circuits may optionally share a common neutral cable terminating on duplex apartment receptacles, a discipline sometimes referred to as “ split-wiring ”, “ split-receptacle ”, [ 41 ] or “ half-split ” .

refer standards [edit ]

The dimensions and configurations for NEMA connectors are given in ANSI/NEMA standard WD-6. [ 2 ] Underwriters Laboratories maintains UL Standard 498, [ 42 ] which specifies construction operation ( e.g. lastingness, electric guard, and fire-resistance ) for NEMA connectors. These extra requirements allow connectors to be manufactured to be compliant with the National Electrical Code. The Defense Logistics Agency and General Services Administration maintain Federal Specification W-C-596 [ 43 ] and its consociate specification sheets. This stipulation references WD-6 and UL 498, and provides extra lastingness and electrical base hit performance criteria for connectors intended for military habit .

See besides [edit ]

References [edit ]

source :
Category : Tutorial

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