From standard IEC 60228 Ed.3.0 and UL 1581 (up to 2000 kcmil) and ASTM B8-11/B231-04 and ICEA S-94-649-2000 (2500 kcmil and above).
Please note that we have added the values for 3000, 3200, and 3500 mm² as published in the IEC 60228 edition 4 committee draft, published 2021-11-12. In this draft, the value for aluminium with 2500 mm² was changed from 0.0127 to 0.0119. The new value is in fact more reasonable and so we decided to use this value even though the edition 4 is only draft. If you want to use the value from the currently still valid edition 3, you can set it manually in the cable editor.
The fact that triplex or three core cables are twisted together leads to the possible need of a correction factor, the lay length factor $F_{lay}$, to take into account the longer length of the cores, considering the length of lay $L_{lay}$. If the manufacturer provides an electrical resistance value, the electrical resistance value must be valid for the cable, meaning that the $F_{lay}$ should already be included. This holds for any type of power cable, including three-core constructions and cables that are delivered as triplex constructions. Correction factors for lay length are not required where conductors comply with IEC 60228 but they are required for AWG/kcmil conductors to IEC TR 62602 and are given in that publication.If the electrical resistance of a power cable is not provided by the manufacturer, the lay lengths must be taken into account manually. Then, the electrical resistance calculated on the basis of the conductor cross section must be multiplied by the $F_{lay}$ to take the effect of the twisting into account, refer to Cigre TB 880 Guidance Point 23.
The tabulated standard DC resistance values for cable conductors at 20°C are in $\Omega$/km. For calculation, values in in $\Omega$/m are used.
${10}^9\frac{\rho_c}{A_c}$ | at 20°C IEC 60287 |
${10}^9F_{lay,c} \frac{\rho_c}{n_{cw} \left(\frac{d_{cw}}{2}\right)^2 \pi}$ | at 20°C Cigre TB 880 GP 20 |
Size | Area mm² | solid copper plain | solid copper coated | solid alu | stranded copper plain | stranded copper coated | stranded alu | flexible class 5/C copper plain | flexible class 5/C copper coated | flexible class 6/D copper plain | flexible class 6/D copper coated |
---|---|---|---|---|---|---|---|---|---|---|---|
26 AWG | 0.128 | 138 | 143 | 225 | 140 | 150 | 230 | ||||
24 AWG | 0.205 | 85.9 | 89.3 | 141 | 87.6 | 94.2 | 144 | ||||
22 AWG | 0.324 | 54.3 | 56.4 | 88.9 | 55.4 | 59.4 | 90.9 | ||||
0.5 mm$^2$ | 0.5 | 36.0 | 36.7 | 57.47 | 36.0 | 36.7 | 57.47 | 39.0 | 40.1 | 39.0 | 40.1 |
20 AWG | 0.519 | 33.9 | 35.2 | 55.4 | 34.6 | 36.7 | 57.1 | ||||
0.75 mm$^2$ | 0.75 | 24.5 | 24.8 | 38.31 | 24.5 | 24.8 | 38.31 | 26.0 | 26.7 | 26.0 | 26.7 |
18 AWG | 0.823 | 21.4 | 22.2 | 35.1 | 21.8 | 23.2 | 35.8 | ||||
1.0 mm$^2$ | 1.0 | 18.1 | 18.2 | 28.74 | 18.1 | 18.2 | 28.74 | 19.5 | 20.0 | 19.5 | 20.0 |
16 AWG | 1.31 | 13.5 | 14.0 | 22.0 | 13.7 | 14.6 | 22.5 | ||||
1.5 mm$^2$ | 1.5 | 12.1 | 12.2 | 19.16 | 12.1 | 12.2 | 19.16 | 13.3 | 13.7 | 13.3 | 13.7 |
14 AWG | 2.08 | 8.45 | 8.78 | 13.8 | 8.62 | 8.96 | 14.1 | 8.7 | 9.24 | 8.61 | 9.25 |
2.5 mm$^2$ | 2.5 | 7.41 | 7.56 | 11.49 | 7.41 | 7.56 | 11.49 | 7.98 | 8.21 | 7.98 | 8.21 |
12 AWG | 3.31 | 5.31 | 5.53 | 8.71 | 5.43 | 5.64 | 8.88 | 5.48 | 5.81 | 5.53 | 5.94 |
4 mm$^2$ | 4.0 | 4.61 | 4.7 | 7.18 | 4.61 | 4.7 | 7.18 | 4.95 | 5.09 | 4.95 | 5.09 |
10 AWG | 5.261 | 3.343 | 3.476 | 5.479 | 3.409 | 3.546 | 5.589 | 3.45 | 3.66 | 3.48 | 3.73 |
6 mm$^2$ | 6.0 | 3.08 | 3.11 | 4.79 | 3.08 | 3.11 | 4.79 | 3.3 | 3.39 | 3.3 | 3.39 |
8 AWG | 8.367 | 2.102 | 2.163 | 3.446 | 2.144 | 2.23 | 3.515 | 2.18 | 2.33 | 2.18 | 2.35 |
10 mm$^2$ | 10.0 | 1.83 | 1.84 | 3.08 | 1.83 | 1.84 | 3.08 | 1.91 | 1.95 | 1.91 | 1.95 |
6 AWG | 13.3 | 1.323 | 1.363 | 2.168 | 1.348 | 1.403 | 2.211 | 1.38 | 1.46 | 1.39 | 1.49 |
16 mm$^2$ | 16.0 | 1.15 | 1.16 | 1.91 | 1.15 | 0.16 | 1.91 | 1.21 | 1.24 | 1.21 | 1.24 |
4 AWG | 21.15 | 0.8315 | 0.8559 | 1.363 | 0.8481 | 0.882 | 1.39 | 0.865 | 0.918 | 0.873 | 0.937 |
25 mm$^2$ | 25.0 | 0.727 | 1.2 | 0.727 | 0.734 | 1.2 | 0.78 | 0.795 | 0.78 | 0.795 | |
3 AWG | 26.67 | 0.6595 | 0.6788 | 1.081 | 0.6727 | 0.6996 | 1.103 | 0.686 | 0.728 | 0.699 | 0.744 |
2 AWG | 33.62 | 0.5231 | 0.5384 | 0.8574 | 0.5335 | 0.5548 | 0.8745 | 0.547 | 0.58 | 0.554 | 0.595 |
35 mm$^2$ | 35.0 | 0.524 | 0.868 | 0.524 | 0.529 | 0.868 | 0.554 | 0.565 | 0.554 | 0.565 | |
1 AWG | 42.41 | 0.4146 | 0.4268 | 0.6798 | 0.423 | 0.4398 | 0.6934 | 0.434 | 0.46 | 0.44 | 0.472 |
50 mm$^2$ | 50.0 | 0.387 | 0.641 | 0.387 | 0.391 | 0.641 | 0.386 | 0.393 | 0.386 | 0.393 | |
1/0 AWG | 53.49 | 0.3287 | 0.3367 | 0.539 | 0.3354 | 0.3487 | 0.5498 | 0.344 | 0.357 | 0.349 | 0.374 |
2/0 AWG | 67.43 | 0.2608 | 0.267 | 0.4275 | 0.266 | 0.2766 | 0.4361 | 0.272 | 0.284 | 0.276 | 0.3 |
70 mm$^2$ | 70.0 | 0.268 | 0.443 | 0.268 | 0.27 | 0.443 | 0.272 | 0.277 | 0.272 | 0.277 | |
3/0 AWG | 85.01 | 0.2069 | 0.2119 | 0.3392 | 0.211 | 0.2194 | 0.3459 | 0.216 | 0.224 | 0.221 | 0.238 |
95 mm$^2$ | 95.0 | 0.193 | 0.32 | 0.193 | 0.195 | 0.32 | 0.206 | 0.21 | 0.206 | 0.21 | |
4/0 AWG | 107.2 | 0.164 | 0.168 | 0.2689 | 0.1673 | 0.1722 | 0.2743 | 0.172 | 0.18 | 0.175 | 0.189 |
120 mm$^2$ | 120.0 | 0.153 | 0.253 | 0.153 | 0.154 | 0.253 | 0.161 | 0.164 | 0.161 | 0.164 | |
250 kcmil | 127.0 | 0.1416 | 0.1473 | 0.2322 | 0.146 | 0.125 | 0.149 | 0.159 | |||
150 mm$^2$ | 150.0 | 0.124 | 0.206 | 0.124 | 0.126 | 0.206 | 0.129 | 0.132 | 0.129 | 0.132 | |
300 kcmil | 152.0 | 0.118 | 0.1227 | 0.1935 | 0.121 | 0.126 | 0.123 | 0.133 | |||
350 kcmil | 177.0 | 0.1011 | 0.1052 | 0.1659 | 0.104 | 0.108 | 0.106 | 0.114 | |||
185 mm$^2$ | 185.0 | 0.101 | 0.164 | 0.0991 | 0.1 | 0.164 | 0.106 | 0.108 | 0.106 | 0.108 | |
400 kcmil | 203.0 | 0.08851 | 0.09109 | 0.145 | 0.0911 | 0.0948 | 0.0928 | 0.0997 | |||
240 mm$^2$ | 240.0 | 0.0775 | 0.125 | 0.0754 | 0.0762 | 0.125 | 0.0801 | 0.0817 | 0.0801 | 0.0817 | |
500 kcmil | 253.0 | 0.0708 | 0.07287 | 0.1161 | 0.0729 | 0.0758 | 0.0743 | 0.0798 | |||
300 mm$^2$ | 300.0 | 0.062 | 0.1 | 0.0601 | 0.0607 | 0.1 | 0.0641 | 0.0654 | 0.0641 | 0.0654 | |
600 kcmil | 304.0 | 0.059 | 0.06135 | 0.09673 | 0.0613 | 0.0638 | 0.0619 | 0.0664 | |||
700 kcmil | 355.0 | 0.05057 | 0.05205 | 0.08291 | 0.0525 | 0.0547 | 0.053 | 0.0569 | |||
750 kcmil | 380.0 | 0.04721 | 0.04858 | 0.07738 | 0.0491 | 0.051 | 0.0495 | 0.0531 | |||
400 mm$^2$ | 400.0 | 0.0465 | 0.0778 | 0.047 | 0.0475 | 0.0778 | 0.0486 | 0.0495 | |||
800 kcmil | 405.0 | 0.04425 | 0.04554 | 0.07251 | 0.046 | 0.0478 | 0.0464 | 0.0499 | |||
900 kcmil | 456.0 | 0.03933 | 0.04048 | 0.06448 | 0.0409 | 0.0425 | 0.0413 | 0.0443 | |||
500 mm$^2$ | 500.0 | 0.0605 | 0.0366 | 0.0369 | 0.0605 | 0.0384 | 0.0391 | ||||
1000 kcmil | 507.0 | 0.0354 | 0.03643 | 0.05804 | 0.0368 | 0.0382 | 0.0371 | 0.0399 | |||
630 mm$^2$ | 630.0 | 0.0469 | 0.0283 | 0.0286 | 0.0469 | 0.0287 | 0.0292 | ||||
1250 kcmil | 633.0 | 0.02833 | 0.02915 | 0.04643 | 0.0295 | 0.0306 | |||||
1500 kcmil | 760.0 | 0.0236 | 0.02429 | 0.03869 | 0.0245 | 0.0255 | |||||
800 mm$^2$ | 800.0 | 0.0367 | 0.0221 | 0.0224 | 0.0367 | ||||||
1750 kcmil | 887.0 | 0.02023 | 0.02082 | 0.03316 | 0.021 | 0.0218 | |||||
1000 mm$^2$ | 1000.0 | 0.0291 | 0.0176 | 0.0177 | 0.0291 | ||||||
2000 kcmil | 1013.0 | 0.0177 | 0.01822 | 0.02902 | 0.0184 | 0.0192 | |||||
2250 kcmil | 1140.0 | 0.0156 | 0.0156 | 0.0255 | |||||||
1200 mm$^2$ | 1200.0 | 0.0247 | 0.0151 | 0.0151 | 0.0247 | ||||||
2500 kcmil | 1270.0 | 0.014 | 0.0144 | 0.0229 | |||||||
1400 mm$^2$ | 1400.0 | 0.0129 | 0.0129 | 0.0212 | |||||||
2750 kcmil | 1393.0 | 0.0126 | 0.0126 | 0.0209 | |||||||
3000 kcmil | 1520.0 | 0.0117 | 0.012 | 0.0192 | |||||||
1600 mm$^2$ | 1600.0 | 0.0113 | 0.0113 | 0.0186 | |||||||
3500 kcmil | 1770.0 | 0.0101 | 0.0104 | 0.0166 | |||||||
1800 mm$^2$ | 1800.0 | 0.0101 | 0.0101 | 0.0165 | |||||||
2000 mm$^2$ | 2000.0 | 0.009 | 0.009 | 0.0149 | |||||||
4000 kcmil | 2030.0 | 0.0088 | 0.0091 | 0.0145 | |||||||
4500 kcmil | 2280.0 | 0.0079 | 0.0082 | 0.013 | |||||||
2500 mm$^2$ | 2500.0 | 0.0072 | 0.0072 | 0.0127 | |||||||
5000 kcmil | 2530.0 | 0.00715 | 0.0074 | 0.0117 | |||||||
3000 mm$^2$ | 3000.0 | 0.006 | 0.006 | 0.0099 | |||||||
3200 mm$^2$ | 3200.0 | 0.0056 | 0.0056 | 0.0093 | |||||||
3500 mm$^2$ | 3500.0 | 0.0051 | 0.0051 | 0.0085 |