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American wire gauge



 
 
American wire gauge (AWG), also known as the Brown & Sharpe
Brown & Sharpe

Brown & Sharpe is today a division of Hexagon Metrology, Inc., a multinational corporation focused mainly on metrology tools and technology. During the 19th and 20th centuries, Brown & Sharpe was one of the most well-known and influential firms in the machine tool industry....
 wire gauge
, is a standardized
Standardization

Standardization is the process of developing and agreeing upon Standard . A standard is a document that establishes uniform engineering or technical specifications, criteria, methods, processes, or practices....
 wire gauge
Wire gauge

Wire gauge is a measurement of how large a wire is, either in diameter or cross section area. This determines the amount of electric current a wire can safety carry, as well as its electrical resistance and weight per Units of measurement of length....
 system used since 1857 predominantly in the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 for the diameters of round, solid, nonferrous, electrically
Electricity

Electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena such as lightning and static electricity, but in addition, less familiar concepts such as the electromagnetic field and electromagnetic induction....
 conducting
Electrical conduction

Electrical conduction is the movement of electric charge particles through a transmission medium . The movement of charge constitutes an Current ....
 wire. The cross-sectional area of each gauge is an important factor for determining its current-carrying capacity
Ampacity

Ampacity, also described as current rating or current-carrying capacity, is the Root mean square electric current which a device can continuously carry while remaining within its temperature rating....
.

The steel industry uses different wire gauges (for example, W&M Wire Gauge or US Steel Wire Gauge, or Music Wire Gauge).






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American wire gauge (AWG), also known as the Brown & Sharpe
Brown & Sharpe

Brown & Sharpe is today a division of Hexagon Metrology, Inc., a multinational corporation focused mainly on metrology tools and technology. During the 19th and 20th centuries, Brown & Sharpe was one of the most well-known and influential firms in the machine tool industry....
 wire gauge
, is a standardized
Standardization

Standardization is the process of developing and agreeing upon Standard . A standard is a document that establishes uniform engineering or technical specifications, criteria, methods, processes, or practices....
 wire gauge
Wire gauge

Wire gauge is a measurement of how large a wire is, either in diameter or cross section area. This determines the amount of electric current a wire can safety carry, as well as its electrical resistance and weight per Units of measurement of length....
 system used since 1857 predominantly in the United States
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 for the diameters of round, solid, nonferrous, electrically
Electricity

Electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena such as lightning and static electricity, but in addition, less familiar concepts such as the electromagnetic field and electromagnetic induction....
 conducting
Electrical conduction

Electrical conduction is the movement of electric charge particles through a transmission medium . The movement of charge constitutes an Current ....
 wire. The cross-sectional area of each gauge is an important factor for determining its current-carrying capacity
Ampacity

Ampacity, also described as current rating or current-carrying capacity, is the Root mean square electric current which a device can continuously carry while remaining within its temperature rating....
.

The steel industry uses different wire gauges (for example, W&M Wire Gauge or US Steel Wire Gauge, or Music Wire Gauge). The table below does not apply to steel wire.

Increasing gauge numbers give decreasing wire diameters, which is similar to many other non-metric
Si

Si, si, or SI may refer to :...
 gauging systems. This gauge system originated in the number of drawing operations
Wire drawing

Wire drawing is a metalworking process used to reduce the diameter of a wire by pulling the wire through a single, or series of, drawing die ....
 used to produce a given gauge of wire. Very fine wire (for example, 30 gauge) requires more passes through the drawing dies
Die (manufacturing)

A die is a specialized tool used in manufacturing industries to cut, shape and form a wide variety of products and components. Like Molding and templates, dies are generally customized and uniquely matched to the product they are used to create....
 than does 0 gauge wire. Manufacturers of wire formerly had proprietary wire gauge systems; the development of standardized wire gauges rationalized selection of wire for a particular purpose.

The AWG tables are for a single, solid, round conductor. The AWG of a stranded wire is determined by the total cross-sectional area of the conductor, which determines its current-carrying capacity and electrical resistance
Electrical resistance

The electrical resistance of an object is a measure of its opposition to the passage of a steady electrical current. An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material....
. Because there are also small gaps between the strands, a stranded wire will always have a slightly larger overall diameter than a solid wire with the same AWG.

The AWG size is one of the essential specifications that are printed on data cables. For instance, an AWG of 24 is common for network cables such as a Category 5
Category 5 cable

Category 5 cable, is a twisted pair high signal integrity cable type often refered to as "Cat5". Many such cables are shield but some are shielded....
 UTP, and an AWG of 26 is the norm for Serial ATA
Serial ATA

The Serial ATA computer bus is a storage-interface for connecting Host adapter to mass storage devices .Conceptually, SATA is a 'wire replacement' for the older AT Attachment standard ....
 cables.

AWG is also commonly used to specify body piercing
Body piercing

Body piercing is the practice of puncturing or cutting a part of the human body, creating an opening in which body piercing jewelry may be worn....
 jewelry sizes, especially smaller sizes.

Formula

By definition, No. 36 AWG is 0.0050 inches in diameter, and No. 0000 is 0.4600 inches in diameter. The ratio of these diameters is 92, and there are 40 gauge sizes from No. 36 to No. 0000, or 39 steps. Using this common ratio, wire gauge sizes vary geometrically according to the following formula: The diameter of a No. n AWG wire is

the gauge can be calculated from the diameter using



and the cross-section area is .

Sizes with multiple zeros are successively larger than No. 0 and can be denoted using "number of zeros/0", for example 4/0 for 0000. For an m/0 AWG wire, use n = −(m−1) = 1−m in the above formulas. For instance, for No. 0000 or 4/0, use n = -3.

The ASTM B 258-02 standard defines the ratio between successive sizes to be the 39th root of 92, or approximately 1.1229322. ASTM B 258-02 also dictates that wire diameters should be tabulated with no more than 4 significant figures, with a resolution of no more than 0.0001 inches (0.1 mils) for wires larger than No. 44 AWG, and 0.00001 inches (0.01 mils) for wires No. 45 AWG and smaller.

Rules of Thumb

The sixth power of this ratio is very close to 2, which leads to the following rules of thumb:
  • When the diameter of a wire is doubled, the AWG will decrease by 6. (e.g. No. 2 AWG is about twice the diameter of No. 8 AWG.)
  • When the cross-sectional
    Cross section (geometry)

    In geometry, a cross-section is the intersection of a body in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc....
     area
    of a wire is doubled, the AWG will decrease by 3. (e.g. Two No. 14 AWG wires have about the same cross-sectional area as a single No. 11 AWG wire.)


Additionally, a decrease of ten gauge numbers, for example from No. 10 to 1/0, multiplies the area and weight by approximately 10 and reduces the resistance by approximately 10.

Table of AWG wire sizes

The table below shows various data including both the resistance of the various wire gauges and the allowable current (ampacity
Ampacity

Ampacity, also described as current rating or current-carrying capacity, is the Root mean square electric current which a device can continuously carry while remaining within its temperature rating....
) based on plastic insulation. The diameter information in the table applies to solid wires. Stranded wires are calculated by calculating the equivalent cross sectional
Cross section (geometry)

In geometry, a cross-section is the intersection of a body in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc....
 copper area
Area

Area is a quantity expressing the two-dimensional size of a defined part of a surface, typically a region bounded by a closed curve. The term surface area refers to the total area of the exposed surface of a 3-dimensional solid, such as the sum of the areas of the exposed sides of a polyhedron....
. The table below assumes DC
Direct current

Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as battery , thermocouples, solar cells, and commutator-type electric machines of the dynamo type....
, or AC
Alternating current

In alternating current the movement of electric charge periodically reverses direction. An electric charge would for instance move forward, then backward, then forward, then backward, over and over again....
 frequencies equal to or less than 60 Hz, and does not take skin effect
Skin effect

The skin effect is the tendency of an alternating current to distribute itself within a Conductor so that the current density near the surface of the conductor is greater than that at its core....
 into account. Turns of wire is on a best-case scenario when winding tightly packed coils with no insulation.

AWG Diameter Turns of wire Area Copper
Copper

Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity....

resistance
Electrical resistance

The electrical resistance of an object is a measure of its opposition to the passage of a steady electrical current. An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material....
 
NEC copper wire
ampacity
Ampacity

Ampacity, also described as current rating or current-carrying capacity, is the Root mean square electric current which a device can continuously carry while remaining within its temperature rating....
 with 60/75/
90°C insulation (A)
Approximate
stranded metric
equivalents
(inch)(mm) (per inch) (per cm) (kcmil
Circular mil

A circular mil is a Units of measurement of area, equal to the area of a circle with a diameter of one Thou . A mil is one thousandth of an inch....
)
(mm˛)(O/km) (O/kFT)
0000 (4/0) 0.4600 11.684 2.17 0.856 212 107 0.1608 0.04901 195 / 230 / 260  
000 (3/0) 0.4096 10.404 2.44 0.961 168 85.0 0.2028 0.06180 165 / 200 / 225  
00 (2/0) 0.3648 9.266 2.74 1.08 133 67.4 0.2557 0.07793 145 / 175 / 195  
0 (1/0) 0.3249 8.252 3.08 1.21 106 53.5 0.3224 0.09827 125 / 150 / 170  
1 0.2893 7.348 3.46 1.36 83.7 42.4 0.4066 0.1239 110 / 130 / 150  
2 0.2576 6.544 3.88 1.53 66.4 33.6 0.5127 0.1563 95 / 115 / 130  
3 0.2294 5.827 4.36 1.72 52.6 26.7 0.6465 0.1970 85 / 100 / 110 196/0.4
4 0.2043 5.189 4.89 1.93 41.7 21.2 0.8152 0.2485 70 / 85 / 95  
5 0.1819 4.621 5.50 2.16 33.1 16.8 1.028 0.3133 126/0.4
6 0.1620 4.115 6.17 2.43 26.3 13.3 1.296 0.3951 55 / 65 / 75  
7 0.1443 3.665 6.93 2.73 20.8 10.5 1.634 0.4982 80/0.4
8 0.1285 3.264 7.78 3.06 16.5 8.37 2.061 0.6282 40 / 50 / 55  
9 0.1144 2.906 8.74 3.44 13.1 6.63 2.599 0.7921 84/0.3
10 0.1019 2.588 9.81 3.86 10.4 5.26 3.277 0.9989 30 / 35 / 40
11 0.0907 2.305 11.0 4.34 8.23 4.17 4.132 1.260 56/0.3
12 0.0808 2.053 12.4 4.87 6.53 3.31 5.211 1.588 25 / 25 / 30 (20)  
13 0.0720 1.828 13.9 5.47 5.18 2.62 6.571 2.003 50/0.25
14 0.0641 1.628 15.6 6.14 4.11 2.08 8.286 2.525 20 / 20 / 25 (15)  
15 0.0571 1.450 17.5 6.90 3.26 1.65 10.45 3.184 30/0.25
16 0.0508 1.291 19.7 7.75 2.58 1.31 13.17 4.016 — / — / 18 (10)
17 0.0453 1.150 22.1 8.70 2.05 1.04 16.61 5.064 32/0.2
18 0.0403 1.024 24.8 9.77 1.62 0.823 20.95 6.385 — / — / 14 (7) 24/0.2
19 0.0359 0.912 27.9 11.0 1.29 0.653 26.42 8.051  
20 0.0320 0.812 31.3 12.3 1.02 0.518 33.31 10.15 16/0.2
21 0.0285 0.723 35.1 13.8 0.810 0.410 42.00 12.80  
22 0.0253 0.644 39.5 15.5 0.642 0.326 52.96 16.14 7/0.25
23 0.0226 0.573 44.3 17.4 0.509 0.258 66.79 20.36  
24 0.0201 0.511 49.7 19.6 0.404 0.205 84.22 25.67 1/0.5, 7/0.2, 30/0.1
25 0.0179 0.455 55.9 22.0 0.320 0.162 106.2 32.37  
26 0.0159 0.405 62.7 24.7 0.254 0.129 133.9 40.81 7/0.15
27 0.0142 0.361 70.4 27.7 0.202 0.102 168.9 51.47  
28 0.0126 0.321 79.1 31.1 0.160 0.0810 212.9 64.90  
29 0.0113 0.286 88.8 35.0 0.127 0.0642 268.5 81.84  
30 0.0100 0.255 99.7 39.3 0.101 0.0509 338.6 103.2 1/0.25, 7/0.1
31 0.00893 0.227 112 44.1 0.0797 0.0404 426.9 130.1  
32 0.00795 0.202 126 49.5 0.0632 0.0320 538.3 164.1 1/0.2, 7/0.08
33 0.00708 0.180 141 55.6 0.0501 0.0254 678.8 206.9  
34 0.00630 0.160 159 62.4 0.0398 0.0201 856.0 260.9  
35 0.00561 0.143 178 70.1 0.0315 0.0160 1079 329.0  
36 0.00500 0.127 200 78.7 0.0250 0.0127 1361 414.8  
37 0.00445 0.113 225 88.4 0.0198 0.0100 1716 523.1  
38 0.00397 0.101 252 99.3 0.0157 0.00797 2164 659.6  
39 0.00353 0.0897 283 111 0.0125 0.00632 2729 831.8  
40 0.00314 0.0799 318 125 0.00989 0.00501 3441 1049  


The "Approximate stranded metric equivalents" column lists commonly available cables in the format "number of strands / diameter of individual strand (mm)" which is the common nomenclature describing cable construction within an overall cross-sectional area. Some common cables are midway between two AWG sizes. Cables sold in Europe are normally labeled according to the combined cross section of all strands in mm˛, which can be compared directly with the Area column.

In the North American electrical industry, conductors larger than 4/0 AWG are generally identified by the area in thousands of circular mils (kcmil), where 1 kcmil = 0.5067 mm˛. A circular mil
Circular mil

A circular mil is a Units of measurement of area, equal to the area of a circle with a diameter of one Thou . A mil is one thousandth of an inch....
 is the area of a wire one mil
Thou (unit of length)

A thou, also known as a mil or point, is a Units of measurement of length equal to 0.001 inch . It is sometimes used in engineering and in the specification of:...
 in diameter. One million circular mils is the area of a cylinder with 1000 mil = 1 inch diameter. An older abbreviation for one thousand circular mils is MCM.

Outside North America, wire sizes for electrical purposes are usually given as the cross sectional area in square millimeters. International standard
International standard

International standards are standards developed by international standards organisations. International standards are available for consideration and use, worldwide....
 manufacturing sizes for conductors in electrical cables are defined in IEC 60228
IEC 60228

IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables.Among other things, it defines a set of standard wire cross-sectional areas:...
.

Note that the area in mm˛ may differ somewhat from the numbers given in the table, depending on number of strands etc.

Pronunciation

AWG is colloquially referred to as gauge and the zeros in large wire sizes are referred to as aught . Wire sized 1 AWG is referred to as "one gauge"; similarly, smaller diameters are pronounced "x gauge", where x is the positive integer AWG number. Larger wire (#0 and up) is referred to as "one aught", "two aught" etc, depending on how many zeros are in the AWG rating.

See also

  • IEC 60228
    IEC 60228

    IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables.Among other things, it defines a set of standard wire cross-sectional areas:...
     for international standard wire sizes
  • British Standard Gauge
    Standard wire gauge

    Great Britain Standard Wire Gauge is a set of wire sizes given by BS 3737:1964, and is generally abbreviated to SWG. Use of SWG sizes has fallen greatly in popularity, but is still in use....
  • A chart comparing all known wire gauges
  • Number 8 wire
    Number 8 wire

    Number 8 wire is a gauge of wire on the American wire gauge that has entered into the cultural lexicon of New ZealandNumber 8 wire is often used inventively and practically for applications other than for fencing....
    , a term used in the New Zealand vernacular


Further reading

  • Donald G. Fink and H. Wayne Beaty, Standard Handbook for Electrical Engineers, Eleventh Edition,McGraw-Hill, New York, 1978, ISBN 0-07-020974-X, page 4-18 and table 4-11.


External links

  • - Online calculator converts gauge to diameter or diameter to gauge for any wire size.