Power Copper Conductors According to IEC 60228

Tinned conductors

Cross section

cl.2

cl.5

Cross section

cl.2

cl.5

mm²

Ohm/km

Ohm/km

mm²

Ohm/km

Ohm/km

1.0

18.2

20

70

0.270

0.277

1.5

12.2

13.7

95

0.195

0.210

2.5

7.56

8.21

120

0.154

0.164

4

4.70

5.09

150

0.126

0.132

6

3.11

3.39

185

0.100

0.108

10

1.84

1.95

240

0.0762

0.0817

16

1.16

1.24

300

0.0607

0.0654

25

0.734

0.795

400

0.0475

0.0495

35

0.529

0.565

500

0.0369

0.0391

50

0.391

0.393

630

0.0286

0.0292

Plain conductors

Cross section

cl.2

cl.5

Cross section

cl.2

cl.5

mm²

Ohm/km

Ohm/km

mm²

Ohm/km

Ohm/km

1

18.1

19.5

70

0.268

0.272

1.5

12.1

13.3

95

0.193

0.206

2.5

7.41

7.98

120

0.153

0.161

4

4.61

4.95

150

0.124

0.129

6

3.08

3.30

185

0.0991

0.106

10

1.83

1.91

240

0.0754

0.0801

16

1.15

1.21

300

0.0601

0.0641

25

0.727

0.780

400

0.0470

0.0486

35

0.524

0.554

500

0.0366

0.0384

50

0.387

0.386

630

0.0283

0.0287

Correction factors according to IEC 60228

IEC 60228 standard provides electrical resistance of copper conductors at an ambient temperature of 20°C.

For other temperatures, correction factors are applied as below:

Temperature (°C)

Kt

5

1.064

10

1.042

15

1.020

20

1.000

25

0.980

30

0.962

35

0.943

40

0.926

45

0.909

50

0.893

55

0.877

60

0.862

65

0.847

70

0.833

75

0.820

80

0.806

85

0.794

90

0.781

95

0.769

100

0.758