The following formula can be used in conjunction with the table shown below to get an approximate AWG value for a cable with a known number of conductors, with each conductor having a known diameter.
S1 = (πD2) / 4
∑S = n.S1
As an example, let's assume we want to know the AWG for a copper conductor cable having 41 strands of 0.20mm wire.
First we need to calculate the area of a single strand:
0.20 × 0.20 = 0.04
0.04 × 3.14 = 0.1256
0.11256 ÷ 4 = 0.0314
Then we need to get the (approximate) area for 41 strands:
41 × 0.0314 = 1.2874
Now we use the table below to find the AWG number for a cable with an area of 1.29mm2 (an approximation is close enough for all practical applications).
Nominal Area (mm2) | AWG Value | Nominal Area (mm2) | AWG Value | Nominal Area (mm2) | AWG Value | Nominal Area (mm2) | AWG Value |
33.62 | 2 | 2.627 | 13 | 0.205 | 24 | 0.0159 | 35 |
29.94 | 2.5 | 2.336 | 13.5 | 0.183 | 24.5 | 0.0142 | 35.5 |
26.66 | 3 | 2.082 | 14 | 0.162 | 25 | 0.0127 | 36 |
23.75 | 3.5 | 1.855 | 14.5 | 0.145 | 25.5 | 0.0112 | 36.5 |
21.149 | 4 | 1.652 | 15 | 0.128 | 26 | 0.0103 | 37 |
18.840 | 4.5 | 1.472 | 15.5 | 0.114 | 26.5 | 0.00894 | 37.5 |
16.766 | 5 | 1.308 | 16 | 0.102 | 27 | 0.00811 | 38 |
14.938 | 5.5 | 1.167 | 16.5 | 0.0910 | 27.5 | 0.00694 | 38.5 |
13.298 | 6 | 1.040 | 17 | 0.0804 | 28 | 0.00621 | 39 |
11.846 | 6.5 | 0.924 | 17.5 | 0.0718 | 28.5 | 0.00552 | 39.5 |
10.551 | 7 | 0.823 | 18 | 0.0647 | 29 | 0.00487 | 40 |
9.400 | 7.5 | 0.732 | 18.5 | 0.0569 | 29.5 | 0.00456 | 40.5 |
8.367 | 8 | 0.653 | 19 | 0.0507 | 30 | 0.00397 | 41 |
7.456 | 8.5 | 0.582 | 19.5 | 0.0457 | 30.5 | 0.00343 | 41.5 |
6.631 | 9 | 0.519 | 20 | 0.0401 | 31 | 0.00317 | 42 |
5.910 | 9.5 | 0.462 | 20.5 | 0.0358 | 31.5 | 0.00292 | 42.5 |
5.261 | 10 | 0.412 | 21 | 0.0324 | 32 | 0.00245 | 43 |
4.689 | 10.5 | 0.367 | 21.5 | 0.0285 | 32.5 | 0.00223 | 43.5 |
4.168 | 11 | 0.324 | 22 | 0.0255 | 33 | 0.00203 | 44 |
3.713 | 11.5 | 0.289 | 22.5 | 0.0277 | 33.5 | 0.00183 | 44.5 |
3.308 | 12 | 0.259 | 23 | 0.0201 | 34 | ||
2.950 | 12.5 | 0.230 | 23.5 | 0.0176 | 34.5 |
For our example, we get an AWG of 16