Ampacities of Insulated Conductors (From NEC Table 310-16) Not More than Three Conductors in Raceway or Cable or Earth (Directly Buried) | |||||||
Size | Copper Conductors | Aluminum Conductors Copper-Clad Conductors | |||||
60°C (140°F) | 75°C (167°F) | 90°C (194°F) | 60°C (140°F) | 75°C (167°F) | 90°C (194°F) | ||
Wire Size | Types | Types | Types | Types | Types | Types | |
TW, UF | RHW, THW, THWN, XHHW, USE, ZW | TBS, SA, SIS, FEP, FEPB, RHH, THHN, THWN, XHHW | TW, UF | RHW, THHW, THW, THWN, XHHW, USE | TBS, SA, SIS, THHN, THHW, THW-2, THWN-2, RHH, RHW-2, USE-2, XHH, XHHW, XHHW-2, ZW-2 | ||
AWG or Kcmil | mm2 | ||||||
18 | 0.8 | - | - | 14 | - | - | - |
16 | 1.3 | - | - | 18 | - | - | - |
141 | 2.1 | 20 | 20 | 25 | - | - | - |
121 | 3.3 | 25 | 25 | 30 | 201 | 201 | 251 |
101 | 5.3 | 30 | 35 | 40 | 25 | 301 | 351 |
8 | 8.4 | 40 | 50 | 55 | 30 | 40 | 45 |
6 | 13.3 | 55 | 65 | 75 | 40 | 50 | 60 |
4 | 21.2 | 70 | 85 | 95 | 55 | 65 | 75 |
3 | 26.7 | 85 | 100 | 110 | 65 | 75 | 85 |
2 | 33.6 | 95 | 115 | 130 | 75 | 90 | 100 |
1 | 42.4 | 110 | 130 | 150 | 85 | 100 | 115 |
1/0 | 53.5 | 125 | 150 | 170 | 100 | 120 | 135 |
2/0 | 67.4 | 145 | 175 | 195 | 115 | 135 | 150 |
3/0 | 85.0 | 165 | 200 | 225 | 130 | 155 | 175 |
4/0 | 107 | 195 | 230 | 260 | 150 | 180 | 205 |
250 | 127 | 215 | 255 | 290 | 170 | 205 | 230 |
300 | 152 | 240 | 285 | 320 | 190 | 230 | 255 |
350 | 177 | 260 | 310 | 350 | 210 | 250 | 280 |
400 | 203 | 280 | 335 | 380 | 225 | 270 | 305 |
500 | 253 | 320 | 380 | 430 | 260 | 310 | 350 |
600 | 304 | 355 | 420 | 475 | 285 | 340 | 385 |
700 | 355 | 385 | 460 | 520 | 310 | 375 | 420 |
750 | 380 | 400 | 475 | 535 | 320 | 385 | 435 |
800 | 405 | 410 | 490 | 555 | 330 | 395 | 450 |
900 | 456 | 435 | 520 | 585 | 355 | 425 | 480 |
1000 | 507 | 455 | 545 | 615 | 375 | 445 | 500 |
1250 | 633 | 495 | 590 | 665 | 405 | 485 | 545 |
1500 | 760 | 520 | 625 | 705 | 435 | 520 | 585 |
1750 | 887 | 545 | 650 | 735 | 455 | 545 | 615 |
2000 | 1013 | 560 | 665 | 750 | 470 | 560 | 630 |
1The load current rating and the overcurrent protection for conductor types shall not exceed 15 amperes for 14 AWG, 20 amperes for 12 AWG, and 30 amperes for 10 AWG aluminum and copper-clad aluminum after any correction factors for ambient temperature and number of conductors have been applied. |
Correction Factors for Ambient Temperature Over30°C, 86° F | ||||||
Ambient Temperature | For Ambient Temperatures Over 30° C, 86° F, multiply the ampacities shown above by the appropriate factor show below: | |||||
21-25°C, 70-77°F | 1.08 | 1.05 | 1.04 | 1.08 | 1.05 | 1.04 |
26-30°C, 78-86°F | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
31-35°C, 87-95°F | .91 | .94 | .96 | .91 | .94 | .96 |
36-40°C, 96-104°F | .82 | .88 | .91 | .82 | .88 | .91 |
41-45°C, 105-113°F | .71 | .82 | .87 | .71 | .82 | .87 |
46-50°C, 114-122°F | .58 | .75 | .82 | .58 | .75 | .82 |
51-55°C, 123-131°F | .41 | .67 | .76 | .41 | .67 | .76 |
56-60°C, 132-140°F | - | .58 | .71 | - | .58 | .71 |
61-70°C, 141-158°F | - | .33 | .58 | - | .33 | .58 |
71-80°C, 159-176°F | - | - | .41 | - | - | .41 |
3-Wire residential services, allowable ampacities [From NEC Table 310-15(B)(6)] | ||
Copper AWG | Aluminum AWG | Service Ampacity |
4 | 2 | 100 |
3 | 1 | 110 |
2 | 1/0 | 125 |
1 | 2/0 | 150 |
1/0 | 3/0 | 175 |
2/0 | 4/0 | 200 |
3/0 | 250 kcmil | 225 |
4/0 | 300 kcmil | 250 |