Misplaced Pages

#854145

98-590: The National Emergency Alarm Repeater (NEAR) was a civilian emergency warning device in the United States. It was a 2–3" (5–7.5 cm) square box designed to plug into a standard power outlet to receive a special signal sent over the electric power transmission lines. Research and testing for the NEAR program was developed in 1956 during the Cold War to supplement the existing siren warning systems and radio broadcasts in

196-528: A fuse rated to protect its flexible cord from overload and consequent fire risk. Modern appliances may only be sold with a fuse of the appropriate size pre-installed. The United Kingdom, Ireland, and Malta use the BS ;4573 two-pin plug and socket for electric shavers and toothbrushes. The plug has insulated sleeves on the pins. Although similar to the Europlug Type ;C, the diameter and spacing of

294-507: A single connector body, for mating with a complementary connector with opposite gender pins in corresponding positions. For example, CEE 7/5 sockets have a male Ground pin. In these unusual cases, gender is often defined by the shape of the connector body , rather than the mixed-gender connector pins and sockets . These types of connectors are not strictly speaking hermaphroditic, since mating connectors are not freely interchangeable. An informal term that has been used for these connectors

392-551: A (non-compliant) variant of IEC 60906-1 as the national standard in 1998 under specification NBR 14136 (revised in 2002). These are used for both 220-volt and 127-volt regions of the country, despite the IEC ;60906-2 recommendation that NEMA 5-15 be used for 120 V connections. There are two types of sockets and plugs in NBR ;14136: one for 10 A, with a 4.0 mm pin diameter, and another for 20 A, with

490-468: A 10 A plug will fit all sockets but a 20 A plug will fit only 20, 25 and 32 A sockets. In New Zealand, PDL 940 "tap-on" or "piggy-back" plugs are available which allow a second 10 A plug to be fitted to the rear of the plug. In Australia these piggy-back plugs are now available only on pre-made extension leads. Australia's standard plug/socket system was originally codified as standard C112 (floated provisionally in 1937, and adopted as

588-524: A 20 A version, the original motivation to use the NEMA ;10-20 plug has ceased to exist. This Australian/New Zealand standard is used in Australia, New Zealand, Fiji, Tonga, Solomon Islands, and Papua New Guinea. It defines a plug with an earthing pin, and two flat current-carrying pins which form an inverted V-shape. The flat pins measure 6.5 by 1.6 mm (0.256 by 0.063 in) and are set at 30° to

686-523: A 4.8 mm pin diameter. This differs from IEC 60906-1 which specifies a pin diameter of 4.5 mm and a rating of 16 A. NBR 14136 does not require shutters on the apertures, a further aspect of non-compliance with IEC 60906-1. NBR 14136 was not enforced in that country until 2007, when its adoption was made optional for manufacturers. It became compulsory on 1 January 2010. Few private houses in Brazil have an earthed supply, so even if

784-432: A detachable power cord (mains flex lead) and appropriate plug in order to avoid manufacturing whole appliances, with the only difference being the type of plug. Alternatively, the plug itself can often be swappable using standard or proprietary connectors. Adaptors between standards are not included in most standards, and as a result they have no formal quality criteria defined. Physical compatibility does not ensure that

882-442: A fire when plugged into an extension cord with a current rating lower than necessary. Sometimes the cords used to plug in dual voltage 120 V / 240 V equipment are rated only for 125 V, so care must be taken by travellers to use only cords with an appropriate voltage rating. Various methods can be used to increase the number or reach of sockets. Extension cords (extension leads) are used for temporary connections when

980-441: A fixed location is a "jack", and a moveable connector is a "plug". The distinction is relative, so a portable radio is considered stationary compared to the cable from the headphones; the radio has a jack, and the headphone cable has a plug. Where the relationship is equal, such as when two flexible cables are connected (an "inline" connection), each is considered a plug. Jacks use the reference designator prefix of J and plugs use

1078-414: A formal standard in 1938), which was based on a design patented by Harvey Hubbell and was superseded by AS 3112 in 1990. The requirement for insulated pins was introduced in the 2004 revision. The current version is AS/NZS 3112:2011, Approval and test specification – Plugs and socket-outlets . Brazil, which had been using mostly Europlugs, and NEMA 1-15 and NEMA 5-15 standards, adopted

SECTION 10

#1733085303855

1176-661: A headphone lead. In Romania, female connectors are known as mamă ("mother") and male connectors are tată ("father"). The standard letters "M" and "F" are commonly used in part numbers to designate connector gender. For example, in Switchcraft XLR microphone or hydrophone connectors, the part numbers are denoted as follows: The terms plug , pin , and prong are also often used for "male" connectors, and receptacle , socket , and slot are used for "female" connectors. In many cases these terms are more common than male and female , especially in documentation intended for

1274-420: A lengthy hose and reverse it because it has the wrong gender to connect to another hose. Some military fiber optical cables also have hermaphroditic connectors to prevent "wrong gender" connector problems in field deployments. In a similar fashion, railcars are usually equipped with hermaphroditic railway coupling mechanisms that allow either end of the vehicle to be connected to a train without having to turn

1372-633: A list of approved plug and socket technical standards used in the member countries. The plug and socket system used in Class ;1 applications in Argentina is defined by IRAM standards. These two standards are; IRAM 2073 "Two pole plugs with earthing contact for domestic and similar purposes, rated 10 A and 20 A, 250 V AC" and IRAM 2071 "Two pole socket – outlets with earthing contact for 10 A and 20 A, 250 V AC., for fixed installations." The plug and socket system

1470-413: A part of the electronic device accepting the power). Although the plug is female, with a partially recessed center contact, it is still possible for casual accidental contact with a metallic object to short-circuit the power source. Depending on the design of the power adapter, it may react to a short circuit by shutting down temporarily, or instead by blowing out an internal safety fuse . In this example,

1568-468: A receptacle for impurity, for use as s'chach 18th-century dictionaries and encyclopedias mention male and female screws or cochleae. A 1736 builder's manual mentions screw genders as metaphors for convex and concave shapes: If the furrowed surface be convex, 'tis called a Male Screw ; if concave, a Female ; and where Motion is to be generated, the Male and Female are always join'd. In mechanical design,

1666-475: A rubber gasket to make the final connection. Downspouts (also called downpipes, rain conductors, or leaders) are used to convey rainwater from roof gutters to the ground through hollow pipes or tubes. These tubes usually come in sections, joined by inserting the male end (often crimped with a special tool to slightly reduce its size) into the female end of the next section. These connections are usually not sealed or caulked, instead relying on gravity to move

1764-482: A single system. When an enforced sense of unidirectionality or "one-way flow" is required for safety or other reasons (for example, AC electrical power connections), a strict assignment of connector genders is implemented to prevent undesired configurations, and gender changers are banned. Some commonly seen examples of hermaphroditic connectors include the SAE connector for 12 V DC power , jackhammer air hose connectors, and

1862-528: A size 1 shell can be named DE9M or DE9P; a female standard-density D-sub with a size 2 shell can be named DA15F or DA15S; a male high-density D-sub with a size 3 shell can be named DB44M or DB44P; and so forth. Electronic designers often select female jack connectors for fixed mounting on electronic equipment they design. This is usually done because female connectors are more resistant to damage or contamination, by virtue of their concealed or recessed electrical contacts. A damaged motherboard connector can result in

1960-430: A socket is not within convenient reach of an appliance's power lead. This may be in the form of a single socket on a flexible cable or a power strip with multiple sockets. A power strip may also have switches, surge voltage protection, or overcurrent protection. Multisocket adaptors (or "splitters") allow the connection of two or more plugs to a single socket. They are manufactured in various configurations, depending on

2058-567: A special male IEC 60320 C14 connector (see the gallery above), which is recessed below the surface of a mounting panel, providing the desired physical protection while conforming to safety regulations. In the case of consumer-level AC power, connector gender is used to implicitly enforce safe use of power connectors. Because of this consideration, it is illegal under electrical code to make or use any gender changers to connect AC line power to consumer-level equipment. A double-ended male connector for utility-supplied ("mains") electrical power

SECTION 20

#1733085303855

2156-421: A standard connector, for example a female RP-TNC connector has a solid innermost pin. Another ambiguous situation arises with the connectors used for USB , FireWire (IEEE-1394), HDMI , and Thunderbolt serial data bus connections. Close examination of these connectors reveals that the contact "pins" are not actually pins, but instead are conductive surfaces that slide past each other when they mate. Therefore,

2254-570: A switch for the selection of voltage. The plugs and sockets used in a given area are regulated by local governments. The International Electrotechnical Commission (IEC) maintains a guide with letter designations for generally compatible types of plugs, which expands on earlier guides published by the United States Department of Commerce . This is a de facto naming standard and guide to travellers. Some letter types correspond to several current ratings or different technical standards, so

2352-467: A third pin for a safety connection to earth ground. The plug is a male connector, usually with protruding pins that match the openings and female contacts in a socket. Some plugs also have a female contact, used only for the earth ground connection . Typically no energy is supplied to any exposed pins or terminals on the socket. In addition to the recessed contacts of the energised socket, plug and socket systems often have other safety features to reduce

2450-674: A three-pin socket is present it is not safe to assume that all three terminals are actually connected. Most large domestic appliances were sold with the option to fit a flying earth tail to be locally earthed, but many consumers were unsure how to use this and so did not connect it. The new standard has an earth pin, which in theory eliminates the need for the flying earth tail. BS 546, "Two-pole and earthing-pin plugs, socket-outlets and socket-outlet adaptors for AC (50-60 Hz) circuits up to 250 V" describes four sizes of plug rated at 2 A, 5 A (Type D), 15 A (Type M) and 30 A. The plugs have three round pins arranged in

2548-594: A triangle, with the larger top pin being the earthing pin. The plugs are polarised and unfused. Plugs are non-interchangeable between current ratings. Introduced in 1934, the BS 546 type has mostly been displaced in the UK by the BS 1363 standard. According to the IEC, some 40 countries use Type D and 15 countries use Type M. Some, such as India and South Africa, use standards based on BS 546. BS 1363 "13 A plugs, socket-outlets, adaptors and connection units"

2646-401: A very simple form of genderless connections. Kapla or KEVA planks are extremely simple genderless systems interconnected only by gravity. Mathematicians have begun to classify well-known construction sets using group theory to study the combinatoric possibilities of structures that can be built. In plumbing fittings, the "M" or "F" usually comes at the beginning rather than the end of

2744-582: A voltage sufficient to cause electrical shock, the semi-exposed center contact of the female plug would be considered unacceptably hazardous, requiring a different choice of connector. Some electrical connectors are hermaphroditic because they include both male and female elements in a single unit intended to interconnect freely, without regard for gender. See the discussion of genderless connectors in this article for more detailed information. As an additional complication, certain electronic connector designs may incorporate combinations of male and female pins in

2842-429: Is desired, it is implemented through other means (e.g. air gaps or one-way check valves ), and not through male-female gender schemes. The Talmud describes arrow heads and mating shafts as potentially being either male or female, depending on their construction, i.e. a prong on a male arrow head fits into a hollowed out shaft and vice versa. This is owing to a prohibition on a female shaft, from its susceptibility as

2940-408: Is "bisexual", in addition to the more official terminology, mixed-gender . Thus, for example, one can have a mixed-gender female plug that connects to a mixed-gender male jack (though a reversed gender assignment of connectors would be a more typical design choice in this example). Male connector pins are often protected by a shell (also called a shroud , surround , or shield ), which may envelop

3038-426: Is a registered trademark of a German association established to own the term). The socket has a circular recess with two round holes and two earthing clips that engage before live pin contact is made. The pins are 4.8 by 19 mm (0.189 by 0.748 in). The Schuko system is unpolarised, allowing live and neutral to be reversed. The socket accepts Europlugs and CEE 7/17 plugs and also includes CEE 7/7. It

National Emergency Alarm Repeater - Misplaced Pages Continue

3136-422: Is an example where male and female connectors have been deliberately designed and assigned to physically enforce a safe network topology. In other contexts, such as plumbing, one-way flow is not enforced through connector gender assignment. Flows through piping networks can be bidirectional, as in underground water distribution networks which have designed-in redundancy . In plumbing situations where one-way flow

3234-529: Is centred between the apertures, offset by 10 mm (0.394 in). The plug has two round pins measuring 4.8 by 19 mm (0.189 by 0.748 in), spaced 19 mm (0.748 in) apart and with an aperture for the socket's projecting earth pin. This standard is also used in Belgium , Poland , the Czech Republic , Slovakia and some other countries. Although the plug is polarised, CEE 7 does not define

3332-561: Is considered best practice to use "male" and "female" for connector gender , and "plug" and "jack" for connector function or mobility . In the United Kingdom, many Commonwealth countries , and some non-English-speaking countries such as France, the word "jack" may refer to the plug on the end of a removable cable. These connectors were originally referred to as "jack plugs", or plugs intended to be mated with fixed receptacles, or sockets (which North Americans would call "jacks"), but

3430-442: Is extremely dangerous, and sometimes is called a suicide cable or widowmaker cord . Some hardware shops explicitly refuse to make or sell them when asked by customers who have mistakenly hung a string of Christmas lights backwards and wish to connect the socket end to a wall socket, or who intend to connect a generator or inverter to their home's electrical circuit in the event of a utility power outage. The exposed prongs on

3528-403: Is implemented to enhance safety or ensure proper functionality by preventing unsafe or non-functional configurations from being set up. In terms of mathematical graph theory , an electrical power distribution network made up of plugs and sockets is a directed tree , with the directionality arrows corresponding to the female-to-male transfer of electrical power through each mated connection. This

3626-528: Is more obvious with ring crimp lug connectors which are placed around a screw post, but again with spade or split ring crimp lug connectors the end alone is not obviously female. Further confusion can be caused by the term " jack ", which is used for both female and male connectors and typically refers to the fixed (panel) side of a connector pair. IEEE STD 100, IEEE-315-1975 and IEEE 200-1975 (replaced by ASME Y14.44-2008 ) define " plug " and " jack " by location or mobility, rather than gender. A connector in

3724-405: Is neither applicable nor permitted on plugs and sockets. CEE 7/1 unearthed sockets accept CEE 7/2 round plugs with 4.8 by 19 mm (0.189 by 0.748 in) pins. Because they have no earth connections they have been or are being phased out in most countries. Some countries still permit their use in dry areas, while others allow their sale for replacements only. Older sockets are so shallow that it

3822-445: Is often designed so that the earth ground contact connects before the energized circuit contacts. The assigned IEC appliance class is governed by the requirement for earthing or equivalent protection. Class I equipment requires an earth contact in the plug and socket, while Class II equipment is unearthed and protects the user with double insulation . Where a " neutral " conductor exists in supply wiring, polarisation of

3920-449: Is possible to accidentally touch the live pins of a plug. CEE 7/1 sockets also accept CEE 7/4, CEE 7/6 and CEE 7/7 plugs without providing an earth connection. The earthed CEE 7/3 and CEE 7/5 sockets do not allow insertion of CEE 7/2 unearthed round plugs. The CEE 7/3 socket and CEE 7/4 plug are commonly called Schuko , an abbreviation for Schutzkontakt , Protective contact to earth ("Schuko" itself

4018-686: Is rated at 16 A. The current German standards are DIN  49441 and DIN 49440. The standard is used in Germany and several other European countries and on other continents. Some countries require child-proof socket shutters; the DIN ;49440 standard does not have this requirement. The plug is used in most or many countries of Europe, Asia, and Africa, as well as in the countries of South Korea , Peru , Chile and Uruguay. The few European countries not using it at all are Belgium , Czech Republic , Cyprus , Ireland , Liechtenstein , Switzerland , and

National Emergency Alarm Repeater - Misplaced Pages Continue

4116-479: Is similar in appearance to the Australian and Chinese plugs. It has an earthing pin and two flat current-carrying pins forming an inverted V-shape (120°). The flat pins for the 10 A version measure 6.25 by 1.55 mm (0.246 by 0.061 in) and 8.0 by 1.9 mm (0.315 by 0.075 in) for the 20 A version, and are set at 30° to the vertical at a nominal pitch of 7.92 mm (0.312 in). The pin length

4214-461: Is sufficient to cause injury , the part permanently connected to the power source is invariably female, with concealed contacts, to prevent inadvertent touching of live conductors by people or animals, or by conductive items that may cause a short circuit . A male plug, with fully exposed protruding contacts, is installed on the cord of (or directly onto) the device receiving the power. Devices that need to be robust against mechanical damage may use

4312-503: Is the stackable connector for electronics, which typically has male pins on one surface and complementary female sockets on the opposite surface, allowing multiple units to be stacked up like plastic milk crates . Examples of this include stackable banana plugs, and interconnect cables specified for the IEEE-488 instrumentation bus. Stackable mezzanine bus connectors are used on some modular microcomputer accessory boards for systems such as

4410-423: Is the connector attached to an electrically-operated device, often via a cable. A socket (also known as a receptacle or outlet ) is fixed in place, often on the internal walls of buildings, and is connected to an AC electrical circuit. Inserting ("plugging in") the plug into the socket allows the device to draw power from this circuit. Plugs and wall-mounted sockets for portable appliances became available in

4508-475: Is the main plug and socket type used in the United Kingdom. According to the IEC it is also used in over 50 countries worldwide. Some of these countries have national standards based on BS 1363, including: Bahrain , Hong Kong , Ireland , Cyprus , Malaysia , Malta , Saudi Arabia , Singapore , Sri Lanka , and UAE . This plug has three rectangular pins forming an isosceles triangle. The BS 1363 plug has

4606-515: Is the same as in the Chinese version. The earthing pin length is 21.4 mm (0.843 in) for the 10 A version and 21.8 mm (0.858 in) for the 20 A version. On the plugs, the pole length is 18.2 mm (0.717 in) for the 10 A version and 17.8 mm (0.701 in) for the 20 A version. The most important difference from the Australian plug is that the Argentine plug

4704-422: Is usually loosely adhered to for simplicity of design, and to reduce the number of gender changer fittings required, but exceptions are made whenever expedient. Although the gender of tubing and plumbing fittings is usually obvious, this may not be true of electrical connectors because of their more complex and varying constructions. Instead, connector gender is conventionalized and thus can be somewhat obscure to

4802-502: Is wired with the live and neutral contacts reversed. In Brazil, similar plugs and sockets are still commonly used in old installations for high-power appliances like air conditioners, dishwashers, and household ovens. Although being often called "Argentine plug," it is actually based on the American NEMA ;10-20 standard, and is incompatible with Argentine IRAM plugs. Since Brazil adopted the NBR 14136 standard which includes

4900-558: The Arduino add-on daughterboards called "shields". The older PC/104 embedded PC modules use a similar stackable format for interconnection. Stackable connectors are not classified as hermaphroditic in the strictest sense, but are often described as such in looser usage. The hermaphroditic design is useful when multiple complex or lengthy components must be arbitrarily connected in various combinations. For example, if hoses have hermaphroditic fittings, they can be connected without having to pull

4998-527: The UK , or not using it predominantly are Denmark , Faroe Island , France , Italy , Monaco , San Marino , Slovakia . French standard NF C 61-314 defines the CEE ;7/5 socket and CEE 7/6 plug, (and also includes CEE 7/7, 7/16 and 7/17 plugs). The socket has a circular recess with two round holes. The round earth pin projecting from the socket connects before the energized contacts touch. The earth pin

SECTION 50

#1733085303855

5096-462: The reference designator prefix of P. It is common practice to use female connectors for jacks, so the informal gender-based usage often happens to agree with the functional description of the technical standards. However, this is not always the case; often-seen exceptions include a computer's AC Power Inlet and EIA232 DE9 Serial Port, or the male coaxial power jacks for connecting external power adapters to portable equipment. To summarize, it

5194-545: The 1880s, to replace connections to light sockets. A proliferation of types were subsequently developed for both convenience and protection from electrical injury . 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, and many obsolete socket types are still found in older buildings. Coordination of technical standards has allowed some types of plug to be used across large regions to facilitate

5292-509: The United States Army, and a manufacturer of sockets point out a number of safety issues with universal socket and adaptors, including voltage mismatch, exposure of live pins, lack of proper earth ground connection, or lack of protection from overload or short circuit. Universal sockets may not meet technical standards for durability, plug retention force, temperature rise of components, or other performance requirements, as they are outside

5390-575: The abbreviated designation. For example: A short length of pipe having an MIP thread at both ends is sometimes called a nipple . A short pipe fitting having an FIP thread at both ends is sometimes called a coupling . Hermaphroditic connections, which may include both male and female elements in a single unit, are used for some specialized tubing fittings, such as Storz fire hose connectors. A picture of such fittings appears in § Genderless (hermaphroditic) , below. Interchangeable garden hose fittings made by GEKA are also hermaphroditic, relying on

5488-418: The appliance and socket match in frequency or voltage. Adaptors allow travellers to connect devices to foreign sockets, but do not change voltage or frequency. A voltage converter is required for electrical compatibility in places with a different voltage than the device is designed for. Mismatch in frequency between supply and appliances may still cause problems even at the correct voltage. Some appliances have

5586-410: The canonical LEGO plastic blocks have "female" indentations on the lower surface, and "male" bosses or protrusions on the upper surfaces. Meccano and Erector have many gendered connections, starting with the nut-and-bolt fasteners they use frequently. Stickle bricks , using interlocking plastic protrusions, are effectively genderless (while nonetheless maintaining an asymmetry). Lincoln logs use

5684-401: The common "patch cables" used for Ethernet (and the similar cords used for telephones ) typically have male modular plugs on both ends, to connect to jacks on equipment or mounted in walls. An example of a design tradeoff in power connector selection is a coaxial power connector , which is usually set up so that power is fed from the female plug into the male jack (which is typically

5782-439: The country and the region in which they are used, with various ratings. This allows connecting more than one electrical consumer item to one single socket and is mainly used for low power devices (TV sets, table lamps, computers, etc.). They are usually rated at 6 A 250 V, 10 A 250 V, or 16 A 250 V. This is the general rating of the adaptor, and indicates the maximum total load in amps, regardless of

5880-401: The entire female connector when mated. RF connectors often have multiple layers of interlocking shells to properly connect the shields of coaxial and triaxial cable . In such cases, the gender is assigned based on the innermost connecting point. With the exception of reverse polarity BNC or TNC, where the outer shell determines the gender and the innermost connecting points are opposite to

5978-558: The event of a nuclear attack. The advent of the radio Emergency Broadcast System rendered NEAR obsolete, although a severe disadvantage inherent in the Emergency Broadcast System was that it required a television or radio to be turned on for a household to receive the emergency alarm, whereas NEAR did not. Despite this advantage, upon the introduction of the Emergency Broadcast System, stockpiled NEAR repeaters were destroyed by their respective manufacturers. A similar program

SECTION 60

#1733085303855

6076-616: The false impression that it is hermaphroditic. However, a physical attempt to mate two USB "Type A" cables with each other reveals the fact that the connectors will not interconnect. Classifying according to mathematical graph theory , USB buses are directed trees , whereas FireWire buses have a true bus network topology. This difference is reflected in the bus connectors used, in that USB cables are asymmetrical (one end Type A, other end Type B) while FireWire cables may have identical connectors at both ends. The more-recent USB-C cables may also have identical connectors on both ends (in which case

6174-441: The first three-pin earthed (grounded) plugs appeared. Over time other safety improvements were gradually introduced to the market. The earliest national standard for plug and wall socket forms was set in 1915. Designs of plugs and sockets have gradually developed to reduce the risk of electric shock and fire. Plugs are shaped to prevent bodily contact with live parts. Sockets may be recessed and plugs designed to fit closely within

6272-412: The hot blade, so it can only be inserted one way. Wiring systems where both circuit conductors have a significant potential with respect to earth do not benefit from polarised plugs. Plugs and power cords have a rated voltage and current assigned to them by the manufacturer. Using a plug or power cord that is inappropriate for the load may be a safety hazard. For example, high-current equipment can cause

6370-480: The imposed current would be generated by special generators and would be at 270 Hz at 3 volts RMS for 50,000 cycles ( U.S. patent 3,284,791 ), approximately three minutes. The indoor buzzers would be supplemented with outdoor warning sirens. An episode of the PBS television program History Detectives suggested that problems with NEAR might have included limited instructions on what to do when an alert

6468-428: The letter does not uniquely identify a plug and socket within the type family, nor guarantee compatibility. Physical compatibility of the plug and socket does not ensure correct voltage, frequency, or current capacity. Not all plug and socket families have letters in the IEC guide, but those that have are noted in this article, as are some additional letters commonly used by retail vendors. In Europe, CENELEC publishes

6566-442: The live end of the cable pose serious electrical shock and fire hazards, and when improperly used in a generator setup may cause the equipment to burn out when utility power is restored. It can also backfeed power into the grid, potentially damaging utility equipment or even electrocuting linemen attempting to restore power. Similarly, an exposed connection on a jumper cable for a 12V automotive battery can be hazardous, because of

6664-522: The live wires in the wall behind it. Some also have an integrated cover (e.g. a hinged flap) covering the socket itself when not in use, or a switch to turn off the socket. Some plugs have a built-in fuse which breaks the circuit if too much current is passed. A third contact for a connection to earth is intended to protect against insulation failure of the connected device. Some early unearthed plug and socket types were revised to include an earthing pin or phased out in favour of earthed types. The plug

6762-476: The logical A and B ends are negotiated between the attached devices rather than being directly indicated by the plugs). An example of a connector where the contacts themselves are hermaphroditic is the ELCO Varicon, wherein the contacts are bifurcated in recessed cross-shaped wells, and mate with one another axially at a 90 degree rotation. In this example, the plugs have the contacts oriented transversely and

6860-439: The marginal reliability of the connector choice was deemed to be acceptable by the equipment designer, since the power adapter supplies low voltage that does not pose an electric shock hazard. The potential fire hazard from accidental short-circuiting is addressed by the internal safety fuse, although this requires that a failed power adapter be completely replaced. In a different design, if the power adapter were intended to supply

6958-408: The non-specialist. These nearly synonymous terms can cause a fair amount of confusion when the designations are shortened in labels. For example, a female high-density D-subminiature connector with a size 1 shell can be named DE15F or DE15S (see accompanying pictures). Both terms mean the same thing but could be construed to be completely different items. Similarly, a male standard-density D-sub with

7056-805: The number of sockets used (for example, if a 16 A 250 V adaptor has four sockets, it would be fine to plug four different devices into it that each consume 2 A as this represents a total load of only 8 A, whereas if only two devices were plugged into it that each consumed 10 A, the combined 20 A load would overload the circuit). In some countries these adaptors are banned and are not available in shops, as they may lead to fires due to overloading them or can cause excessive mechanical stress to wall-mounted sockets. Adaptors can be made with ceramic, Bakelite, or other plastic bodies. "Universal" or "multi-standard" sockets are intended to accommodate plugs of various types. In some jurisdictions, they violate safety standards for sockets. Safety advocates,

7154-419: The other, being designated female . Extension of the analogy results in the verb to mate being used to describe the process of connecting two corresponding parts together. In some cases (notably electrical power connectors), the gender of connectors is selected according to rigid rules, to enforce a sense of one-way directionality (e.g. a flow of power from one device to another). This gender distinction

7252-522: The pins are slightly different and hence it will not fit into a Schuko socket. There are, however, two-pin sockets and adaptors which will accept both BS 4573 and Europlugs. The International Commission on the Rules for the Approval of Electrical Equipment ( IECEE ) was a standards body which published Specification for plugs and socket-outlets for domestic and similar purposes as CEE Publication 7 in 1951. It

7350-476: The placement of the live and neutral, and different countries have conflicting standards for that. For example, the French standard NF C 15-100 requires live to be on the right side, while Czech standard ČSN 33 2180 requires live to be on the left side of a socket. Thus, a French plug when plugged into a Czech socket (or a Czech plug when plugged into a French socket) will always have its polarity reversed, with no way for

7448-410: The plug can improve safety by preserving the distinction in the equipment. For example, appliances may ensure that switches interrupt the line side of the circuit, or can connect the shell of a screw-base lampholder to neutral to reduce electric shock hazard. In some designs, polarised plugs cannot be mated with non-polarised sockets. In NEMA 1 plugs, for example, the neutral blade is slightly wider than

7546-490: The population within 30 seconds after a signal is given by the national civil-defense center in Colorado Springs . The device is a buzzer installed into ordinary electrical outlets. The devices would be set off in an emergency by altering the regular AC signal being generated and transmitted by the local power companies. This would be done by having a specific alternating current of a specific frequency superimposed upon it;

7644-407: The potentially high current and energy involved. Accidental shorting of the wire to vehicle ground can cause sparks, rapid heating, or even a battery explosion. In low-voltage use such as for data communications , electrical shock hazard is not an issue, and male or female connectors are used based on other engineering factors such as convenience of use, cost, or ease of manufacturing. For example,

7742-399: The production and import of electrical appliances and for the convenience of travellers. Some multi-standard sockets allow use of several types of plug. Incompatible sockets and plugs may be used with the help of adaptors, though these may not always provide full safety and performance. Single-phase sockets have two current-carrying connections to the power supply circuit, and may also have

7840-718: The prototypical "male" component is a threaded bolt, but an alignment post, a mounting boss , or a sheet metal tab connector can also be considered as male. Correspondingly, a threaded nut, an alignment hole, a mounting recess, or sheet metal slot connector is considered to be female. While some mechanical designs are "one-off" custom setups not intended to be repeated, there is an entire fastener industry devoted to manufacturing mass-produced or semi-custom components. To avoid unnecessary confusion, conventional definitions of fastener gender have been defined and agreed upon. Several common construction toys embody gendered (and in some cases, genderless) mechanical interconnections. For example,

7938-618: The railcar around first. For the same reason, several spacecraft docking mechanisms are designed to be "androgynous", including the Androgynous Peripheral Attach System , the NASA Docking System , and Chinese Docking Mechanism . In the absence of genderless connectors, gender changer fittings might be used to enable certain connections. The designer of a connection system may use one or both schemes to allow arbitrary connectivity, or even combine both schemes into

8036-596: The rainwater from the male end and into the receiving female connection located directly below. Sheet metal ductwork for conveying air in HVAC systems typically uses gendered connections. Typically, the airflow through a ductwork connection is from male to female. However, since one-way flow is implemented by forced-air fans or blowers, "backwards" gendered connections can be seen frequently in some systems, since all connections are typically sealed with duct sealing mastic or tape to prevent leakage anyway. The flow convention

8134-401: The recess to reduce risk of a user contacting the live pins. Contact pins may be sheathed with insulation over part of their length, so as to reduce exposure of energized metal during insertion or removal of the plug. Sockets may have automatic shutters to stop foreign objects from being inserted into energized contacts. Sockets are often set into a surround which prevents accidental contact with

8232-463: The risk of electric shock or damage to appliances. When commercial electric power was first introduced in the 1880s, it was used primarily for lighting. Other portable appliances (such as vacuum cleaners, electric fans, smoothing irons, and curling-tong heaters) were connected to light-bulb sockets. As early as 1885 a two-pin plug and wall socket format was available on the British market. By about 1910

8330-463: The round earthing pin permanently mounted in the socket; CEE 7/6 plugs are not compatible with Schuko sockets due to the presence of indentations on the side of the recess, as well as the earth clips. CEE 7/7 plugs have been designed to solve this incompatibility by being able to fit in either type of socket. Sales and installations of 7/5 sockets are legally permitted in Denmark since 2008, but

8428-881: The scope of national and international technical standards. A technical standard may include compatibility of a socket with more than one form of plug. The Thai dual socket is specified in figure 4 of TIS 166-2549 and is designed to accept Thai plugs, and also Type A, B, and C plugs. Chinese dual sockets have both an unearthed socket complying with figure 5 of GB 1002-2008 (both flat pin and 4.8 mm round pin), and an earthed socket complying with figure 4 of GB 1002-2008. Both Thai and Chinese dual sockets also physically accept plugs normally fitted to 120 V appliances (e.g. 120 V rated NEMA 1-15 ungrounded plugs). This can cause an electrical incompatibility, since both states normally supply residential power only at 220 V. Commonly, manufacturers provide an IEC 60320 inlet on an appliance, with

8526-490: The scrapping of an expensive piece of electronic equipment. The risk of damage is reduced by relegating the more exposed male contacts to connecting cables, which can be repaired or replaced at lower cost. For example, in an RS-232 serial port , the male connector is more mechanically fragile than the female connector. Cost and reliability considerations probably drove the design decision to use female jack connectors on many computer terminals (and some personal computers) for

8624-559: The second word was dropped. This variant usage is in direct contradiction to common usage and official standards in North America. For example, in the UK, the connector on the end of a headphone lead is known as a "jack", that plugs into a socket on the main unit. The same usage also generally occurs in Italy, where the English word "jack" is commonly used to indicate the connector on the end of

8722-497: The serial port, despite being in direct violation of the connector gender convention explicitly specified in the RS-232 standard for "DTE" ( data terminal equipment ) connections. This confusing reversal of the RS-232 connector gender convention has caused many hours of frustration for ill-informed end users, as they tried to troubleshoot non-functional serial port equipment connections. In electrical connections where voltage or current

8820-888: The sockets are arranged longitudinally. By definition, a hermaphroditic connector includes mating surfaces having simultaneous male and female aspects, involving complementary paired identical parts each containing both protrusions and indentations. These mating surfaces are mounted into identical fittings which can freely mate with any other, without regard for gender (provided that the size and type are already matched). Alternative names include hermaphrodite , androgynous , genderless , sexless , combination (or combo ), two-in-one , two-way , and other descriptive terms. Several of these latter alternate names are ambiguous in meaning, and should not be used unless carefully defined in context. True hermaphroditic connectors should not be confused with mixed gender connectors, which are described elsewhere in this article. Another closely related type

8918-400: The sockets are hard to find in physical stores, and installation is exceedingly rarely performed. Gender of connectors and fasteners The assignment is a direct analogy with male and female genitalia , the part bearing one or more protrusions or which fits inside the other being designated male , in contrast to the part containing the corresponding indentations, or fitting outside

9016-415: The traditional pin and socket nomenclature is not applicable. Instead, most computer hardware people fall back to referring to the wrap-around metal shield on the plug connector as if it were a connector pin . By this convention, the connectors on serial bus cables are "male plugs", and the corresponding connectors on equipment are "female jacks". A casual glance at a USB "Type A" plug connector may give

9114-494: The uninitiated. For example, the female D-subminiature connector body projects outward from the mounting plane of the chassis, and this protrusion could be erroneously construed as male. Instead, the "maleness" of the D-subminiature connectors is defined by specific presence of male pins , rather than by the protrusion of the connector (this is also true for many other pin-based connectors like XLR ). The male/female distinction

9212-476: The user to remedy this situation apart from rewiring the plug. One approach for resolving this situation is taken in Poland, where CEE 7/5 sockets are typically installed in pairs, the upper (upside-down) one having the "French" polarity and the lower one having the "Czech" polarity, so that the user can choose what to plug where. CEE 7/4 (Schuko) plugs are not compatible with the CEE 7/5 socket because of

9310-639: The vertical at a nominal pitch of 13.7 mm (0.539 in). Australian and New Zealand wall sockets (locally often referred to as power points ) almost always have switches on them for extra safety, as in the UK. An unearthed version of this plug with two angled power pins but no earthing pin is used with double-insulated appliances, but the sockets always include an earth contact. There are several AS/NZS 3112 plug variants, including ones with larger or differently shaped pins used for devices drawing 15, 20, 25 and 32  A . These sockets accept plugs of equal or lower current rating, but not higher. For example,

9408-702: Was last updated by Modification 4 in March 1983. CEE 7 consists of general specifications and standard sheets for specific connectors. Standard plugs and sockets based on two round pins with centres spaced at 19 mm are in use in Europe, most of which are listed in IEC/TR ;60083 "Plugs and socket-outlets for domestic and similar general use standardized in member countries of IEC." EU countries each have their own regulations and national standards; for example, some require child-resistant shutters, while others do not. CE marking

9506-471: Was proposed in the United Kingdom during the 1960s. A Time magazine article in the 14 November 1960 issue outlined a new program supplementing the then "basically unsound" warning system consisting of localized sirens and the CONELRAD radio-alert system. The United States Army argued that in the age of intercontinental ballistic missiles a civil-defense warning system should be capable of warning 90% of

9604-419: Was received and the device's inability to provide information on what exactly was happening. EMP effects of a high-altitude nuclear detonation could have disabled the system. After a decade of federal support for testing and development, the program was terminated. Power outlet#NEMA 1-15 AC power plugs and sockets connect devices to mains electricity to supply them with electrical power . A plug

#854145