AWG – American wire gauge

Wire sizes and strand sizes (for non-ferrous metals) can be indicated in two ways on the international level:
in mm or as AWG.

While the actual diameter is used within the metric system, the so-called AWG system represents a codification based on the number of manufacturing steps required.

AWG table - single wires
AWG Diameter
in
Diameter
mm

Cross-
section
cma

Cross-section
mm²
0000 (4/0) 0.4600 11.6840 211599.99 107.2193
000 (3/0) 0.4096 10.4049 167806.34 85.0287
00 (2/0) 0.3648 9.2658 133075.59 67.4304
0 (1/0) 0.3249 8.2515 105535.45 53.4756
1 0.2893 7.3481 83691.75 42.4072
2 0.2576 6.5437 66371.15 33.6308
3 0.2294 5.8273 52634.11 26.6701
4 0.2043 5.1894 41741.38 21.1507
5 0.1819 4.6213 33102.51 16.7733
6 0.1620 4.1154 26251.65 13.3019
7 0.1443 3.6649 20818.85 10.5491
8 0.1285 3.2636 16509.21 8.3653
9 0.1144 2.9064 13093.13 6.6344
10 0.1019 2.5882 10383.13 5.2612
11 0.0907 2.3048 8233.78 4.1721
12 0.0808 2.0525 6529.79 3.3087
13 0.0720 1.8278 5178.33 2.6239
14 0.0641 1.6277 4106.59 2.0808
15 0.0571 1.4495 3256.63 1.6502
16 0.0508 1.2908 2582.56 1.3086
17 0.0453 1.1495 2048.10 1.0378
18 0.0403 1.0237 1624.34 0.8231
19 0.0359 0.9116 1288.08 0.6527
20 0.0320 0.8118 1021.48 0.5176
21 0.0285 0.7229 810.01 0.4104
22 0.0253 0.6438 642.44 0.3255
23 0.0226 0.5733 509.44 0.2581
24 0.0201 0.5106 404.10 0.2048
25 0.0179 0.4547 320.47 0.1624
26 0.0159 0.4049 254.11 0.1288
27 0.0142 0.3606 201.55 0.1021
28 0.0126 0.3211 159.81 0.0810
29 0.0113 0.2859 126.70 0.0642
30 0.0100 0.2546 100.47 0.0509
31 0.0089 0.2268 79.73 0.0404
32 0.0080 0.2019 63.18 0.0320
33 0.0071 0.1798 50.11 0.0254
34 0.0063 0.1601 39.73 0.0201
35 0.0056 0.1426 31.52 0.0160
36 0.0050 0.1270 25.00 0.0127
37 0.0045 0.1131 19.83 0.0100
38 0.0040 0.1007 15.72 0.0080
39 0.0035 0.0897 12.47 0.0063
40 0.0031 0.0799 9.90 0.0050
AWG table – strands
Strand
AWG
Cross
section
mm²
Number
of
wires
Single
wires
AWG
Single
wires
diameter
mm
Conductor
diameter
nom.
mm
Corss
section
CMA
Single
wires
diameter
in
Conductor
diameter
nom.
in
42/70.00347500.0250.0756.860.00100.0030
40/70.00537480.0310.09310.80.00120.0037
38/70.00887460.0400.12017.40.00160.0047
36/70.01427440.0510.15228.00.00200.0060
34/70.02227420.0640.19143.80.00250.0075
32/70.03407400.0790.23767.00.00310.0093
30/70.05707380.1020.3061120.00400.0120
28/70.08907360.1270.3811750.00500.0150
26/70.14007340.1600.4802780.00630.0189
24/70.23007320.2030.6094480.00800.0240
22/70.35007300.2540.7627000.01000.0300
20/70.56007280.3200.96011110.01260.0378
18/70.90007260.4041.21217700.01590.0477
32/190.038519440.0510.25476.00.00200.0100
30/190.060219420.0640.3181190.00250.0125
28/190.093019400.0790.3951830.00310.0156
26/190.150019380.1020.5103040.00400.0201
24/190.240019360.1270.6354750.00500.0250
22/190.380019340.1600.8007540.00630.0315
20/190.620019320.2031.01512160.00800.0400
18/190.960019300.2541.27019000.01000.0500
16/191.200019290.2871.43524260.01130.0565
14/191.900019270.3611.80538310.01420.0711
12/193.100019250.4552.27560880.01790.0896
14/371.874837300.2541.77837000.01000.0700
12/373.000037280.3202.24058740.01260.0882
10/374.700037260.4042.82893540.01590.1113
Definition of "AWG"

AWG is an acronym for "American Wire Gauge" (German translation: "Amerikanische Drahtlehre"). As you may have already concluded, this coding system originates from North America. It reflects a geometric sequence that was introduced in the middle of the 19th century by Joseph Rogers Brown for use in his tool-making company Brown & Sharpe.

The AWG standardized wire gauge system is used to plot diameters and cross-sections of electrical conductors made out of non-ferrous metals, applied to both wires and strands. The AWG graduation is based on the number of drawing steps required to produce a certain diameter. In order for the wire to arrive at the desired diameter, a fairly thick base wire (e.g. 0.8 mm) is drawn through the tapered mouth of a drawing die. Reducing the diameter only works very gradually, i.e. by means of several drawing steps, with the mouths that are used getting smaller and smaller until the final diameter is obtained.

AWG calculation base for single wires

The AWG system clearly defines the range 0000 (4/0) to 36, where all sizes in between adhere to a geometric sequence that comply with the following rule: the AWG figure is a function of the number of drawing steps resulting in ever-decreasing diameters. Even sizes below AWG36 follow the same pattern as they are derived from the size range initially covered.

The unit of the diameter is
in resp. mils = in * 1,000

Cross-sections above 4/0 are indicated in
cmils

Single-wire diameter (d)

The ratio between diameters and corresponding AWG sizes can be found in ASTM B 258-02:

Any diameter can be inferred from an AWG figure by making use of the above formula as follows:

Below you can see the inverse calculation (AWG from diameter):

Single-wire cross-section

As opposed to the usual way of calculating a circular area (single-wire cross-section in mm) according to the formula

the AWG system features a simplified calculation using .

This leads to an AWG cross-section stated in
"circular mil area" cma = (d mils)2.

Example:

AWG36 = 0.005 in = 5 mils

(5 mils)² = 25 cma

AWG calculation base for strands

The AWG figure basically stands for a cross-section only. Therefore, any dimension relative to both single wires as well as strands is expressed as such an AWG figure.

Just to make matters more complicated, it is the construction of a strand that has a crucial impact on some of its major properties like flexibility, resistance, conductivity or tensile strength. This aspect has led to the inclusion of the construction whenever an AWG indication is applied. An AWG28 strand, for instance, may consist of seven AWG36 single wires. This is reflected by the designation "AWG28 7/36".

Practitioners have developed approximations for the quick calculation of strand sizes, which can be employed to a certain extent:

RuleExample
AWG of 7end strand = AWG single wire - 8AWG single wire = 36
36 - 8 = 28
AWG 7end strand = 28
AWG single wire = AWG of 7end strand + 8AWG 7end strand = 28
28 + 8 = 36
AWG single wire = 36
AWG of 19end strand = AWG single wire - 12AWG single wire = 36
36 - 12 = 24
AWG 19end strand = 24
AWG single wire = AWG of 19end strand + 12AWG 19er strand = 24
24 + 12 = 36
AWG single wire = 36
AWG of 37end strand = AWG single wire - 16AWG single wire = 26
26 - 16 = 10
AWG 37end strand = 10
AWG single wire = AWG of 37end strand + 16AWG of 37end strand = 10
10 + 16 = 26
AWG single wire = 26

6 AWG steps down → diameter is doubled
6 AWG steps up → diameter is halved
3 AWG steps down → cross-section is doubled
3 AWG steps up → cross-section is halved

Conclusion

With telephony growing more and more widespread in the middle of the 19th century, the wire industry experienced an extraordinary technological boost. Industry and commerce were using completely different units of measurement at the time. Joseph Rogers Brown contributed to making the American Wire Gauge system the predominant measuring tool, which lead to an increased standardization in this field. This development has continued to influence the entire product range when it comes to wires made from non-ferrous metals.

Ongoing technological progress has caused some fundamental changes to the wire drawing process. Fixed definitions have partly been superseded by individual solutions. This has rendered the drawing process more flexible across the board, thus also facilitating the production of wires beyond the standard AWG sizes. In spite of AWG still being a common scaling factor for cable sizes, it is more and more replaced by the metric system.

Whenever characterizing our wires and strands, we always indicate both units of measurement as far as available.

More about the history of AWG

(sorry, just in German language)

"Polytechnisches Journal"
Article: "Ueber ein gleichförmiges Drahtmaaß"
Author: Anonymus
Reference: 1869, Band 192, Nr. VII. (S. 28–35)
URL: http://dingler.culture.hu-berlin.de/article/pj192/ar192007

Picture of a "Drahtlehre":
http://dingler.culture.hu-berlin.de/journal/page/32213036Z?p=00000050

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