ARTICLE 310: Conductors for General Wiring

NEC Tables 310.71, 310.73 and 310.75

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Table 310.71 Ampacities of an Insulated Three-Conductor Copper Cable Isolated in Air Based on Conductor Temperatures of 90°C (194°F) and 105°C (221°F) and Ambient Air Temperature of 40°C (104°F)

Conductor Size (AWG or kcmil) Temperature Rating of Conductor
2001 - 5000 Volts Ampacity 5001 - 35,000 Volts Ampacity
90°C (194°F) Type MV-90 105°C (221°F) Type MV-105 90°C (194°F) Type MV-90 105°C (221°F) Type MV-105
8 59 66
6 79 88 93 105
4 105 115 120 135
2 140 154 165 185
1 160 180 185 210
1/0 185 205 215 240
2/0 215 240 245 275
3/0 250 280 285 315
4/0 285 320 325 360
250 320 355 360 400
350 395 440 435 490
500 485 545 535 600
750 615 685 670 745
1000 705 790 770 860

Table 310.73 Ampacities of an Insulated Triplexed or Three Single-Conductor Copper Cables in Isolated Conduit in Air Based on Conductor Temperatures of 90°C (194°F) and 105°C (221°F) and Ambient Air Temperature of 40°C (104°F)

Conductor Size (AWG or kcmil) Temperature Rating of Conductor
2001 - 5000 Volts Ampacity 5001 - 35,000 Volts Ampacity
90°C (194°F) Type MV-90 105°C (221°F) Type MV-105 90°C (194°F) Type MV-90 105°C (221°F) Type MV-105
8 55 61
6 75 84 83 93
4 97 110 110 120
2 130 145 150 165
1 155 175 170 190
1/0 180 200 195 215
2/0 205 225 225 255
3/0 240 270 260 290
4/0 280 305 295 330
250 315 355 330 365
350 385 430 395 440
500 475 530 480 535
750 600 665 585 655
1000 690 770 675 755

Table 310.75 Ampacities of an Insulated Three-Conductor Copper Cable in Isolated Conduit in Air Based on Conductor Temperatures of 90°C (194°F) and 105°C (221°F) and Ambient Air Temperature of 40°C (104°F)

Conductor Size (AWG or kcmil) Temperature Rating of Conductor
2001 - 5000 Volts Ampacity 5001 - 35,000 Volts Ampacity
90°C (194°F) Type MV-90 105°C (221°F) Type MV-105 90°C (194°F) Type MV-90 105°C (221°F) Type MV-105
8 52 58
6 69 77 83 92
4 91 100 105 120
2 125 135 145 165
1 140 155 165 185
1/0 165 185 195 215
2/0 190 210 220 245
3/0 220 245 250 280
4/0 255 285 290 320
250 280 315 315 350
350 350 390 385 430
500 425 475 470 525
750 525 585 570 635
1000 590 660 650 725

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