Tables › Conductor Properties

Conductor Properties NEC Ch.9 T.8

Area, diameter, and DC resistance for copper and aluminum conductors. Stranded (Class B) values shown.

Copper Conductors — Stranded (Class B)

Size (AWG/kcmil) Area (cmil) Area (mm²) Strands Diameter (in) DC Resistance at 75°C (Ω/1000ft)
18 AWG 1620 0.823 7 0.046 7.77
16 AWG 2580 1.31 7 0.058 4.89
14 AWG 4110 2.08 7 0.073 3.07
12 AWG 6530 3.31 7 0.092 1.93
10 AWG 10380 5.26 7 0.116 1.21
8 AWG 16510 8.37 7 0.146 0.764
6 AWG 26240 13.3 7 0.184 0.491
4 AWG 41740 21.2 7 0.232 0.308
3 AWG 52620 26.7 7 0.260 0.245
2 AWG 66360 33.6 7 0.292 0.194
1 AWG 83690 42.4 19 0.332 0.154
1/0 105600 53.5 19 0.372 0.122
2/0 133100 67.4 19 0.418 0.0967
3/0 167800 85.0 19 0.470 0.0766
4/0 211600 107 19 0.528 0.0608
250 250000 127 37 0.575 0.0515
300 300000 152 37 0.630 0.0429
350 350000 177 37 0.681 0.0367
400 400000 203 37 0.728 0.0321
500 500000 253 37 0.813 0.0258
600 600000 304 61 0.893 0.0214
700 700000 355 61 0.964 0.0184
750 750000 380 61 0.998 0.0171
800 800000 405 61 1.030 0.0161
900 900000 456 61 1.090 0.0143
1000 1000000 507 61 1.150 0.0129
1250 1250000 633 91 1.289 0.0103
1500 1500000 760 91 1.412 0.00858
1750 1750000 887 127 1.526 0.00735
2000 2000000 1010 127 1.631 0.00643

Aluminum Conductors — Stranded (Class B)

Size (AWG/kcmil) Area (cmil) Area (mm²) Strands Diameter (in) DC Resistance at 75°C (Ω/1000ft)
12 AWG 6530 3.31 7 0.092 3.18
10 AWG 10380 5.26 7 0.116 2.00
8 AWG 16510 8.37 7 0.146 1.26
6 AWG 26240 13.3 7 0.184 0.808
4 AWG 41740 21.2 7 0.232 0.508
3 AWG 52620 26.7 7 0.260 0.403
2 AWG 66360 33.6 7 0.292 0.319
1 AWG 83690 42.4 19 0.332 0.253
1/0 105600 53.5 19 0.372 0.201
2/0 133100 67.4 19 0.418 0.159
3/0 167800 85.0 19 0.470 0.126
4/0 211600 107 19 0.528 0.100
250 250000 127 37 0.575 0.0847
300 300000 152 37 0.630 0.0707
350 350000 177 37 0.681 0.0605
400 400000 203 37 0.728 0.0529
500 500000 253 37 0.813 0.0424
600 600000 304 61 0.893 0.0353
700 700000 355 61 0.964 0.0303
750 750000 380 61 0.998 0.0282
800 800000 405 61 1.030 0.0265
900 900000 456 61 1.090 0.0235
1000 1000000 507 61 1.150 0.0212
1250 1250000 633 91 1.289 0.0169
1500 1500000 760 91 1.412 0.0141
1750 1750000 887 127 1.526 0.0121
2000 2000000 1010 127 1.631 0.0106
Voltage Drop
Use the DC resistance values from this table for voltage drop calculations. The Voltage Drop Calculator uses this same data internally.
Circular Mils
One circular mil (cmil) is the area of a circle with a diameter of one mil (0.001 inch). For kcmil sizes, the number IS the area — a 250 kcmil conductor has an area of 250,000 circular mils.

For reference only. Verify all results with the current NEC and local amendments. See Terms of Use.