View source for American wire gauge

{{short description|North American standard for electrical wire diameters}}
{{redirect|AWG}}
[[File:Wire_gauge_(PSF).png | thumb | right | alt=An image of a standard wire gauge.  | A standard wire gauge]]
'''American Wire Gauge''' ('''AWG''') is a [[logarithm]]ic [[Step function|stepped]] [[Standardization|standardized]] [[wire gauge]] system used since 1857, predominantly in [[North America]], for the diameters of round, solid, nonferrous, [[Electrical resistivity and conductivity|electrically conducting]] [[Electrical wiring|wire]]. Dimensions of the wires are given in [[ASTM International|ASTM]] standard B 258.<ref name="astmb258" /> The cross-sectional area of each gauge is an important factor for determining its [[Ampacity|current-carrying capacity]].

== Origin ==
The AWG originated in the number of [[Wire drawing|drawing operations]] used to produce a given gauge of wire. Very fine wire (for example, 30&nbsp;gauge) required more passes through the [[Draw plate|drawing dies]] than 0&nbsp;gauge wire did. Manufacturers of wire formerly had proprietary wire gauge systems; the development of standardized wire gauges rationalized selection of wire for a particular purpose.

While the AWG is essentially identical to the Brown & Sharpe (B&S) sheet metal gauge, the B&S gauge was designed for use with sheet metals. These are functionally interchangeable, but the use of B&S in relation to wire gauges, rather than sheet metal gauges, is technically improper.

== Specifications ==
Increasing gauge numbers denote [[Logarithmic scale|logarithmically]] decreasing wire diameters, which is similar to many other [[International System of Units|non-metric]] gauging systems such as British [[Standard wire gauge|Standard Wire Gauge]] (SWG). However, AWG is dissimilar to [[IEC 60228]], the [[metric system|metric]] wire-size standard used in most parts of the world, based directly on the wire cross-section area (in square millimetres, mm<sup>2</sup>).

The AWG tables are for a single, solid and round conductor. The AWG of a stranded wire is determined by the cross-sectional area of the equivalent solid conductor. 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.

{{Anchor|body_jewelry}}
=== Formulae ===
By definition, 36 AWG is 0.005 inches in diameter, and 0000 AWG is 0.46&nbsp;inches in diameter. The ratio of these diameters is 1:92, and there are 40 gauge sizes from 36 to 0000, or 39 steps. Because each successive gauge number increases cross sectional area by a constant multiple, diameters [[Geometric progression|vary geometrically]]. Any two successive gauges (e.g., {{var|A}} and {{var|B}}) have diameters whose ratio {{nowrap|(dia. {{var|B}} ÷ dia. {{var|A}})}} is <math>\sqrt [39]{92}</math> (approximately 1.12293), while for gauges two steps apart (e.g., {{var|A}}, {{var|B}}, and {{var|C}}), the ratio of the {{var|C}} to {{var|A}} is about 1.12293<sup>2</sup> ≈ 1.26098. Similarly for gauges ''n'' steps apart the ratio of the first to last gauges is about 1.12293<sup>''n''</sup>.

The diameter of an AWG wire is determined according to the following formula:
:<math qid=Q120635143>d_n = 0.005~\mathrm{inch} \times 92^{(36 - n)/39} = 0.127~\mathrm{mm} \times 92^{(36 - n)/39}</math>

(where {{Var|n}} is the AWG size for gauges from 36 to 0, {{nowrap|{{Var|n}} {{=}} −1}} for 00, {{nowrap|{{Var|n}} {{=}} −2}} for 000, and {{nowrap|{{Var|n}} {{=}} −3}} for 0000. See below for rule.)

or equivalently:
:<math>d_n = e^{-1.12436 - 0.11594n}\ \mathrm{inch} = e^{2.1104 - 0.11594n}\ \mathrm{mm} </math>

The gauge can be calculated from the diameter using&nbsp;<ref>The [[logarithm]] to the base 92 can be computed using any other logarithm, such as [[Common logarithm|common]] or [[natural logarithm]], using log<sub>92</sub>''x'' = (log ''x'')/(log 92).</ref>
:<math>n = -39\log_{92} \left( \frac{d_n}{0.005~\mathrm{inch}} \right) + 36 = -39\log_{92} \left( \frac{d_n}{0.127~\mathrm{mm}} \right) + 36</math>

and the cross-section area is
:<math>A_n = \frac{\pi}{4} d_n^2 \approx 0.000019635~\mathrm{inch}^2 \times 92^{(36 - n)/19.5} \approx 0.012668~\mathrm{mm}^2 \times 92^{(36 - n)/19.5}</math>.

The standard ASTM B258-02 (2008), ''Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors'', defines the ratio between successive sizes to be the 39th [[nth root|root]] of 92, or approximately 1.1229322.<ref>ASTM Standard B258-02, page 4</ref> ASTM B258-02 also dictates that wire diameters should be tabulated with no more than 4 significant figures, with a resolution of no more than 0.0001&nbsp;inches (0.1&nbsp;mils) for wires thicker than 44&nbsp;AWG, and 0.00001&nbsp;inches (0.01&nbsp;mils) for wires 45&nbsp;AWG and thinner.

Sizes with multiple zeros are successively thicker than 0 AWG and can be denoted using "''number of zeros''/0", for example 4/0 AWG for 0000 AWG. For an {{mvar|m}}/0&nbsp;AWG wire, use {{math|''n'' {{=}} −(''m'' − 1) {{=}} 1 − ''m''}} in the above formulas. For instance, for 0000 AWG or 4/0 AWG, use {{math|''n'' {{=}} −3}}.

==== Rules of thumb ====
The sixth power of <math>\sqrt[39]{92}</math> is very close to 2,<ref>The result is 2.0050315..., or one-quarter of one percent higher than 2.</ref> which leads to the following rules of thumb:
* When the ''[[Cross section (geometry)|cross-sectional]] area'' of a wire is doubled, the AWG will decrease by 3; for example, two 14&nbsp;AWG wires have about the same cross-sectional area as a single 11&nbsp;AWG wire. This doubles the [[Electrical resistance and conductance|electrical conductance]].
* When the ''diameter'' of a solid round wire is doubled, the AWG will decrease by 6; for example, 1&nbsp;mm diameter wire is ≈18&nbsp;AWG, 2&nbsp;mm diameter wire is ≈12&nbsp;AWG, and 4&nbsp;mm diameter wire is ≈6&nbsp;AWG. This quadruples the cross-sectional area and conductance.
* A decrease of ten gauge numbers; for example, from 24&nbsp;AWG to 14&nbsp;AWG multiplies the area, weight, and conductance by approximately 10.

Convenient coincidences result in the following rules of thumb for resistances:
* The resistance of copper wire is approximately {{Sfrac|1 Ω|1000 ft}} for 10&nbsp;AWG, {{Sfrac|10 Ω|1000 ft}} for 20&nbsp;AWG, {{Sfrac|100 Ω|1000 ft}} for 30&nbsp;AWG, and so on.<ref>{{cite tech report|series=Circular of the Bureau of Standards No. 31|title=Copper Wire Tables|date=October 1, 1914|edition=3rd|publisher=United States Department of Commerce|url=https://archive.org/details/copperwiretables31unituoft}}</ref>{{Reference page|27}} For an arbitrary gauge ''n'', it's approximately 10<sup>''n''/10</sup>&nbsp;Ω per {{val|10000|u=ft}}.
* Because [[Electrical conductor#Conductor materials|aluminum wire]] has a conductivity of approximately 61% of copper, an aluminum wire has nearly the same resistance as a [[Copper conductor|copper wire]] that is two sizes smaller, which has 62.9% of the area.

===Tables of AWG wire sizes===
The table below shows various data including both the resistance of the various wire gauges and the allowable current ([[ampacity]]) based on a copper conductor with plastic insulation. The diameter information in the table applies to ''solid'' wires. [[Wire#Stranded wire|Stranded wires]] are calculated by calculating the equivalent [[cross section (geometry)|cross sectional]] copper wire [[area]]. Fusing current (melting wire) is estimated based on {{convert|25|°C}} ambient temperature. The table below assumes [[direct current|DC]], or [[Alternating current|AC]] frequencies equal to or less than 60&nbsp;Hz, and does not take [[skin effect]] into account. "Turns of wire per unit length" is the reciprocal of the conductor diameter; it is therefore an upper limit for wire wound in the form of a [[helix]] (see [[solenoid]]), based on uninsulated wire.

{| class="wikitable" style="text-align:center;"
! rowspan=4 | AWG
! rowspan=3 colspan=2 | Diameter
! rowspan=3 colspan=2 | Turns of wire,<br />without<br />insulation
! rowspan=3 colspan=2 | Area
! colspan=8 | [[Copper]] wire
|-
! rowspan=2 colspan=2 | [[Electrical resistivity and conductivity|Length-specific<br />resistance]]<ref name="resperlength">Figure for solid copper wire at {{convert|68|°F}}, (Not in accordance to NEC Codebook 2014 Ch. 9, Table 8) computed based on 100% IACS conductivity of 58.0&nbsp;M[[Siemens (unit)|S]]/m, which agrees with multiple sources:
* {{cite web |url= http://www.powerstream.com/Wire_Size.htm |title=American Wire Gauge table and AWG Electrical Current Load Limits |first=Mark |last=Lund |work=Powerstream.com |access-date=2008-05-02}} (although the ft/m conversion seems slightly erroneous)
* [[Belden Incorporated|Belden]] Master Catalog, 2006, although data from there for gauges 35 and 37–40 seem obviously wrong.
High-purity [[oxygen-free copper]] can achieve up to 101.5% IACS conductivity; ''e.g.'', the [http://www.kanthal.com/en/products/materials-in-wire-and-strip-form/wire/conductive-wire/copper/ Kanthal conductive alloys data sheet] lists slightly lower resistances than this table.</ref>
! colspan=3 | [[Ampacity]] at temperature rating{{efn|For enclosed wire at 30&nbsp;°C ambient,<ref name="ampacity">
''[http://bulk.resource.org/codes.gov/ NFPA 70 National Electrical Code 2014 Edition] {{webarchive |url= https://web.archive.org/web/20081015074713/http://bulk.resource.org/codes.gov/ |date=2008-10-15}}''. Table 310.15(B)(16) (formerly Table 310.16) page 70-161, "Allowable ampacities of insulated conductors rated 0 through 2000 volts, 60°C through 90°C, not more than three current-carrying conductors in raceway, cable, or earth (directly buried) based on ambient temperature of 30°C." Extracts from [[National Electrical Code|NFPA 70]] do not represent the full position of [[National Fire Protection Association|NFPA]] and the original complete Code must be consulted. In particular, the maximum permissible [[Power system protection|overcurrent protection]] devices may set a lower limit.</ref> with given insulation material temperature rating, or for single unbundled wires in equipment for 16&nbsp;AWG and thinner.<ref name="small gauge ampacity">{{cite book |chapter=Table 11: Recommended Current Ratings (Continuous Duty) for electronic equipment and chassis wiring |title=Reference Data for Engineers: Radio, Electronics, Computer and Communications |edition=7th |pages=49–16}}</ref>}}
! colspan=3 | Fusing current<ref name="SHEE">
Computed using equations from {{Citation |title=The Standard Handbook for Electrical Engineers |edition=15th |date=2007 |editor1-first=H. Wayne |editor-last=Beaty |editor2-first=Donald G. |editor2-last=Fink |publisher=McGraw Hill |pages=4–25 |isbn=978-0-07-144146-9}}
</ref><ref name="Brooks">{{Citation |title=Fusing Current: When Traces Melt Without a Trace |first=Douglas G. |last=Brooks |url=http://www.ultracad.com/articles/fusingr.pdf |journal=Printed Circuit Design |date=December 1998 |volume=15 |issue=12 |page=53 |access-date=2016-08-01 |archive-date=2016-03-27 |archive-url=https://web.archive.org/web/20160327190309/http://www.ultracad.com/articles/fusingr.pdf |url-status=dead }}</ref>
|-
! 60&nbsp;°C
! 75&nbsp;°C
! 90&nbsp;°C
! Preece<ref name="PREECE1">
{{Citation |title=On the Heating Effects of Electric Currents |first=W. H. |last=Preece |url= http://rspl.royalsocietypublishing.org/content/36/228-231/464.full.pdf+html |journal=Proceedings of the Royal Society |issue=36 |pages=464–471 |date=1883}}
</ref><ref name="PREECE2">
{{Citation |title=On the Heating Effects of Electric Currents |first=W. H. |last=Preece |url= http://rspl.royalsocietypublishing.org/content/43/258-265/280.full.pdf+html |journal=Proceedings of the Royal Society |volume=II |issue=43 |pages=280–295 |date=1887}}
</ref><ref name="PREECE3">
{{Citation |title=On the Heating Effects of Electric Currents |first=W. H. |last=Preece |url= http://rspl.royalsocietypublishing.org/content/44/266-272/109.full.pdf+html |journal=Proceedings of the Royal Society |volume=III |issue=44 |pages=109–111 |date=1888}}
</ref><ref name="BROOKS1ADAM1">
{{Citation |title=Who Were Preece and Onderdonk? |first1=Douglas G. |last1=Brooks |first2=Johannes |last2=Adam |url= http://pcdandf.com/pcdesign/index.php/magazine/10179-pcb-design-1507 |journal=Printed Circuit Design and Fab |date=29 June 2015}}
</ref>
! colspan=2 | Onderdonk<ref name="STAUFF">
{{Citation |first=E. R. |last=Stauffacher |title=Short-time Current Carrying Capacity of Copper Wire |journal=General Electric Review |volume=31 |issue=6 |date=June 1928 |url= http://ultracad.com/articles/reprints/stauffacher.pdf}}
</ref><ref name="BROOKS1ADAM1" />
|-
! (in)
! (mm)
! (per&nbsp;in)
! (per&nbsp;cm)
! ([[circular mil|kcmil]])
! (mm<sup>2</sup>)
! (mΩ/m{{efn|name=resm|or, equivalently, [[Ohm|Ω]]/km}})
! (mΩ/ft{{efn|name=resft|or, equivalently, Ω/kft}})
! colspan=3 | (A)
! ~10 s
! 1 s
! 32&nbsp;ms
|-
| 0000 (4/0) || 0.4600{{efn|name=def|Exactly, by definition}}
                       || 11.684{{efn|name=def}}
|                                   2.17 || 0.856 || 212 || 107   || 0.1608 || 0.04901|| 195 || 230 || 260 || 3.2 kA || 33 kA   || 182 kA
|-
|  000 (3/0) || 0.4096 || 10.405 || 2.44 || 0.961 || 168 || 85.0  || 0.2028 || 0.06180|| 165 || 200 || 225 || 2.7 kA || 26 kA   || 144 kA
|-
|   00 (2/0) || 0.3648 ||  9.266 || 2.74 || 1.08 || 133  || 67.4  || 0.2557 || 0.07793|| 145 || 175 || 195 || 2.3 kA || 21 kA   || 115 kA
|-
|    0 (1/0) || 0.3249 ||  8.251 || 3.08 || 1.21 || 106  || 53.5  || 0.3224 || 0.09827|| 125 || 150 || 170 || 1.9 kA || 16 kA   || 91 kA
|-
|    1       || 0.2893 ||  7.348 || 3.46 || 1.36 || 83.7 || 42.4  || 0.4066 || 0.1239 || 110 || 130 || 145 || 1.6 kA || 13 kA   || 72 kA
|-
|    2       || 0.2576 ||  6.544 || 3.88 || 1.53 || 66.4 || 33.6  || 0.5127 || 0.1563 ||  95 || 115 || 130 || 1.3 kA || 10.2 kA || 57 kA
|-
|    3       || 0.2294 ||  5.827 || 4.36 || 1.72 || 52.6 || 26.7  || 0.6465 || 0.1970 ||  85 || 100 || 115 || 1.1 kA ||  8.1 kA || 45 kA
|-
|    4       || 0.2043 ||  5.189 || 4.89 || 1.93 || 41.7 || 21.2  || 0.8152 || 0.2485 ||  70 ||  85 ||  95 ||  946 A ||  6.4 kA || 36 kA
|-
|    5       || 0.1819 ||  4.621 || 5.50 || 2.16 || 33.1 || 16.8  || 1.028  || 0.3133 ||colspan=3|         ||  795 A ||  5.1 kA || 28 kA
|-
|    6       || 0.1620 ||  4.115 || 6.17 || 2.43 || 26.3 || 13.3  || 1.296  || 0.3951 ||  55 ||  65 ||  75 ||  668 A ||  4.0 kA || 23 kA
|-
|    7       || 0.1443 ||  3.665 || 6.93 || 2.73 || 20.8 || 10.5  || 1.634  || 0.4982 ||colspan=3|         ||  561 A ||  3.2 kA || 18 kA
|-
|    8       || 0.1285 ||  3.264 || 7.78 || 3.06 || 16.5 || 8.37  || 2.061  || 0.6282 ||  40 ||  50 ||  55 ||  472 A ||  2.5 kA || 14 kA
|-
|    9       || 0.1144 ||  2.906 || 8.74 || 3.44 || 13.1 || 6.63  || 2.599  || 0.7921 ||colspan=3|         ||  396 A ||  2.0 kA || 11 kA
|-
|   10       || 0.1019 ||  2.588 || 9.81 || 3.86 || 10.4 || 5.26  || 3.277  || 0.9989 ||  30 ||  35 ||  40 ||  333 A ||  1.6 kA || 8.9 kA
|-
|   11       || 0.0907 ||  2.305 || 11.0 || 4.34 || 8.23 || 4.17  || 4.132  || 1.260  ||colspan=3|         ||  280 A ||  1.3 kA || 7.1 kA
|-
|   12       || 0.0808 ||  2.053 || 12.4 || 4.87 || 6.53 || 3.31  || 5.211  || 1.588  ||  20 ||  25 ||  30 ||  235 A ||  1.0 kA || 5.6 kA
|-
|   13       || 0.0720 ||  1.828 || 13.9 || 5.47 || 5.18 || 2.62  || 6.571  || 2.003  ||colspan=3|         ||  198 A ||  798 A || 4.5 kA
|-
|   14       || 0.0641 ||  1.628 || 15.6 || 6.14 || 4.11 || 2.08  || 8.286  || 2.525  ||  15 ||  20 ||  25 ||  166 A ||  633 A || 3.5 kA
|-
|   15       || 0.0571 ||  1.450 || 17.5 || 6.90 || 3.26 || 1.65  || 10.45  || 3.184  ||colspan=3|         ||  140 A ||  502 A || 2.8 kA
|-
|   16       || 0.0508 ||  1.291 || 19.7 || 7.75 || 2.58 || 1.31  || 13.17  || 4.016  || 12 || 16 ||  18 ||  117 A ||  398 A || 2.2 kA
|-
|   17       || 0.0453 ||  1.150 || 22.1 || 8.70 || 2.05 || 1.04  || 16.61  || 5.064  ||colspan=3|         ||   99 A ||  316 A || 1.8 kA
|-
|   18       || 0.0403 ||  1.024 || 24.8 || 9.77 || 1.62 || 0.823 || 20.95  || 6.385  || 10 ||   14 ||  16 ||   83 A ||  250 A || 1.4 kA
|-
|   19       || 0.0359 ||  0.912 || 27.9 || 11.0 || 1.29 || 0.653 || 26.42  || 8.051  ||  — ||  — || —     ||   70 A ||  198 A || 1.1 kA
|-
|   20       || 0.0320 ||  0.812 || 31.3 || 12.3 || 1.02 || 0.518 || 33.31  || 10.15  || 5 ||  11 || —   || 58.5 A ||  158 A || 882 A
|-
|   21       || 0.0285 ||  0.723 || 35.1 || 13.8 || 0.810 || 0.410 || 42.00 || 12.80  ||  — ||  — || —     ||   49 A ||  125 A || 700 A
|-
|   22       || 0.0253 ||  0.644 || 39.5 || 15.5 || 0.642 || 0.326 || 52.96 || 16.14  ||  3 ||  7 || —     ||   41 A ||   99 A || 551 A
|-
|   23       || 0.0226 ||  0.573 || 44.3 || 17.4 || 0.509 || 0.258 || 66.79 || 20.36  ||  —   ||  — || —   ||   35 A ||   79 A || 440 A
|-
|   24       || 0.0201 ||  0.511 || 49.7 || 19.6 || 0.404 || 0.205 || 84.22 || 25.67  ||  2.1 ||  3.5 || — ||   29 A ||   62 A || 348 A
|-
|   25       || 0.0179 ||  0.455 || 55.9 || 22.0 || 0.320 || 0.162 || 106.2 || 32.37  ||  —   ||  — || —   ||   24 A ||   49 A || 276 A
|-
|   26       || 0.0159 ||  0.405 || 62.7 || 24.7 || 0.254 || 0.129 || 133.9 || 40.81  ||  1.3 ||  2.2 || — ||   20 A ||   39 A || 218 A
|-
|   27       || 0.0142 ||  0.361 || 70.4 || 27.7 || 0.202 || 0.102 || 168.9 || 51.47  ||  —   ||  — || —   ||   17 A ||   31 A || 174 A
|-
|   28       || 0.0126 ||  0.321 || 79.1 || 31.1 || 0.160 || 0.0810 || 212.9 || 64.90 ||  0.83 ||  1.4 || — ||  14 A ||   24 A || 137 A
|-
|   29       || 0.0113 ||  0.286 || 88.8 || 35.0 || 0.127 || 0.0642 || 268.5 || 81.84 ||  —   ||  — || —   ||   12 A ||   20 A || 110 A
|-
|   30       || 0.0100 ||  0.255 || 99.7 || 39.3 || 0.101 || 0.0509 || 338.6 || 103.2 ||  0.52 || 0.86 || — ||  10 A ||   15 A ||  86 A
|-
|   31       || 0.00893 || 0.227 || 112  || 44.1 || 0.0797 || 0.0404 || 426.9 || 130.1 ||  —  ||  — || —   ||    9 A ||   12 A ||  69 A
|-
|   32       || 0.00795 || 0.202 || 126  || 49.5 || 0.0632 || 0.0320 || 538.3 || 164.1 || 0.32 ||  0.53 || — ||   7 A ||   10 A ||  54 A
|-
|   33       || 0.00708 || 0.180 || 141  || 55.6 || 0.0501 || 0.0254 || 678.8 || 206.9 ||  —  ||  — || —   ||    6 A ||  7.7 A ||  43 A
|-
|   34       || 0.00630 || 0.160 || 159  || 62.4 || 0.0398 || 0.0201 || 856.0 || 260.9 || 0.18 || 0.3 || — ||   5 A ||  6.1 A ||  34 A
|-
|   35       || 0.00561 || 0.143 || 178  || 70.1 || 0.0315 || 0.0160 || 1079  || 329.0 ||  —  ||  — || —   ||    4 A ||  4.8 A ||  27 A
|-
|   36       || 0.00500{{efn|name=def}}
                        || 0.127{{efn|name=def}}
|                                   200  || 78.7 || 0.0250 || 0.0127 || 1361  || 414.8 ||  — ||  — || —     ||   4 A ||  3.9 A ||   22 A
|-
|   37       || 0.00445 || 0.113 || 225  || 88.4 || 0.0198 || 0.0100 || 1716  || 523.1 ||  — ||  — || —     ||   3 A ||  3.1 A ||   17 A
|-
|   38       || 0.00397 || 0.101 || 252  || 99.3 || 0.0157 || 0.00797 || 2164 || 659.6 ||  — ||  — || —     ||   3 A ||  2.4 A ||   14 A
|-
|   39       || 0.00353 || 0.0897 || 283 || 111  || 0.0125 || 0.00632 || 2729 || 831.8 ||  — ||  — || —     ||   2 A ||  1.9 A ||   11 A
|-
|   40       || 0.00314 || 0.0799 || 318 || 125  || 0.00989 || 0.00501 || 3441 || 1049 ||  — ||  — || —     ||   1 A ||  1.5 A ||  8.5 A
|}
{{Notelist}}

In the North American electrical industry, conductors thicker than 4/0&nbsp;AWG are generally identified by the area in thousands of [[circular mil]]s (kcmil), where 1&nbsp;kcmil = 0.5067&nbsp;mm<sup>2</sup>. The next wire size thicker than 4/0 has a cross section of 250&nbsp;kcmil. A ''circular mil'' is the area of a wire one [[Thousandth of an inch|mil]] in diameter. One million circular mils is the area of a circle with 1,000&nbsp;mil (1&nbsp;inch) diameter. An older abbreviation for one thousand circular mils is ''MCM''.

===Stranded wire AWG sizes===
AWG can also be used to describe stranded wire. The AWG of a stranded wire represents the sum of the cross-sectional diameter of the individual strands; the gaps between strands are not counted. When made with circular strands, [[circle packing|these gaps occupy about 25% of the wire area]], thus requiring the overall bundle diameter to be about 13% larger than a solid wire of equal gauge.

Stranded wires are specified with three numbers, the overall AWG size, the number of strands, and the AWG size of a strand. The number of strands and the AWG of a strand are separated by a slash. For example, a 22&nbsp;AWG 7/30 stranded wire is a 22&nbsp;AWG wire made from seven strands of 30&nbsp;AWG wire.

As indicated in the [[#Formulae|Formulae]] and [[#Rules of thumb|Rules of thumb]] sections above, differences in AWG translate directly into ratios of diameter or area. This property can be employed to easily find the AWG of a stranded bundle by measuring the diameter and count of its strands. (This only applies to bundles with circular strands of identical size.) To find the AWG of 7-strand wire with equal strands, subtract 8.4 from the AWG of a strand. Similarly, for 19-strand subtract 12.7, and for 37 subtract 15.6.

Measuring strand diameter is often easier and more accurate than attempting to measure bundle diameter and packing ratio. Such measurement can be done with a wire gauge go-no-go tool or with a caliper or micrometer.

==Nomenclature and abbreviations in electrical distribution==
{{main|Electric power distribution}}
Alternative ways are commonly used in the electrical industry to specify wire sizes as AWG.
* '''4&nbsp;AWG''' (proper)
** '''#4''' (the [[number sign]] is used as an abbreviation of "number")
** '''№&nbsp;4''' (the [[numero sign]] is used as an abbreviation for "number")
** '''No.&nbsp;4''' (an approximation of the numero is used as an abbreviation for "number")
** '''No.&nbsp;4&nbsp;AWG'''
** '''4&nbsp;ga.''' (abbreviation for "gauge")
* '''000&nbsp;AWG''' (proper for thick sizes)
** '''3/0''' (common for thick sizes)  Pronounced "three-aught" or "triple-aught"
** '''3/0&nbsp;AWG'''
** '''#000'''

===Pronunciation===
''AWG'' is colloquially referred to as ''gauge'' and the zeros in thick wire sizes are referred to as ''[[Names for the number 0 in English#Aught|aught]]'' {{IPAc-en|ˈ|ɔː|t}}. Wire sized 1&nbsp;AWG is referred to as "one gauge" or "No.&nbsp;1" wire; similarly, thinner sizes are pronounced "{{var|x}}&nbsp;gauge" or "No.&nbsp;{{var|x}}" wire, where {{var|x}} is the positive-integer AWG number. Consecutive AWG wire sizes thicker than No.&nbsp;1 wire are designated by the number of zeros:
* No.&nbsp;0, often written 1/0 and referred to as "one-aught" or "single-aught" wire
* No.&nbsp;00, often written 2/0 and referred to as "two-aught" or "double-aught" wire
* No.&nbsp;000, often written 3/0 and referred to as "three-aught" or "triple-aught" wire
and so on.

==See also==
*[[IEC 60228]], international standards for wire sizes
*[[French catheter scale|French gauge]]
*[[Brown & Sharpe]]
*[[Circular mil]], North American Electrical industry standard for wires thicker than 4/0.
*[[Birmingham gauge|Birmingham Wire Gauge]]
*[[Birmingham gauge|Stubs Iron Wire Gauge]]
*[[Jewelry wire]]
*[[Body jewelry sizes]], which commonly uses AWGm especially for thinner sizes, even when the material is not metallic.<ref>[http://www.steelnavel.com/reference.asp SteelNavel.com Body Piercing Jewelry Size Reference — illustrating the different ways that size is measured on different kinds of jewelry]</ref>
*[[Electrical wiring]]
*[[Number 8 wire]], a term used in the New Zealand vernacular

==References==
{{Reflist|40em|refs=
<ref name="astmb258">{{cite web |url= http://www.astm.org/Standards/B258.htm |title=ASTM B258-14 Standard Specification for Standard Nominal Diameters and Cross-sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors| publisher=[[ASTM International]] |access-date=22 March 2015 |location=[[West Conshohocken, Pennsylvania]] |archive-url= https://web.archive.org/web/20140722072347/http://www.astm.org/Standards/B258.htm |archive-date=22 July 2014 |url-access=subscription}}</ref>
}}

{{United States Customary Units}}

{{DEFAULTSORT:American Wire Gauge}}
[[Category:Wire gauges]]
[[Category:Customary units of measurement in the United States]]
[[Category:Logarithmic scales of measurement]]