IEC 60228 DC Resistance

Last updated on 2022-06-02 3 mins. to read

The international standard for conductors is IEC 60287.  The standard classifies conductors according to four classes:

- Class 1: solid conductors

- Class 2: stranded conductors

- Class 5: flexible conductors

- Class 6: flexible conductors (more flexible than class 5)

For each class of conductor, the standard defines the maximum allowable resistance at 20 oC:

Maximum Resistance of Conductors in mΩ/m
CSA mm² Copper (plain) Copper (tinned) Aluminium
class 1 & 2 class 5 & 6 class 5 & 6 class 1 & 2
0.5 36.0 39.0 40.1 -
0.75 24.5 26.0 26.7 -
1 18.1 19.5 20.0 -
1.5 12.1 13.3 13.7 -
2.5 7.41 7.98 8.21 -
4 4.61 4.95 5.09 -
6 3.08 3.30 3.39 -
10 1.83 1.91 1.95 3.08
16 1.15 1.21 1.24 1.91
25 0.727 0.78 0.795 1.20
35 0.524 0.554 0.565 0.868
50 0.387 0.386 0.393 0.641
70 0.268 0.272 0.277 0.443
95 0.193 0.206 0.210 0.320
120 0.153 0.161 0.164 0.253
150 0.124 0.129 0.132 0.206
185 0.0991 0.106 0.108 0.164
240 0.0754 0.0801 0.0817 0.125
300 0.0601 0.0641 0.0654 0.100
400 0.0470 0.0486 0.0495 0.0778
500 0.0366 0.0384 0.0391 0.0605
630 0.0283 0.0287 0.0292 0.0469
800 - - - 0.0367
1000 - - - 0.0291
1200 - - - 0.0247

Comments

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David Mullins May 15, 2019 9:41 PM
Is this IEC 60228 or 60287?
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Steven McFadyen May 15, 2019 9:47 PM
IEC 60228 : Conductors of Insulated Cables
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Leandro Freire Jun 02, 2022 12:51 PM
This tables refers to the "Minimum Resistance of Conductors in mΩ/m" or the Maximum?
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Steven McFadyen Jun 02, 2022 2:29 PM
Thanks for pointing out the confusion.  The values are maximum.
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