Ampacities of Copper Wire
Alowable Ampacities of Insulated Conductors Rated 0 through 2000 Volts, 60°C through 90° C (140° F through 194°F) Not more than Three Current-Carrying Conductors in Raceway, Cable, or Earth (Directly Buried), Based on Ambient Temperature of 30° C (86° F). This Data is based on NEC Table 310-16.
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Temperature Rating of Conductor (See NEC Table 310-13) |
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Wire
|
60° C (140° F) |
75° C (167° F) |
90° C (194° F) |
60° C (140° F) |
75° C (167° F) |
90° C (194° F) |
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Types: TW, UF |
Types: FEPW, RH, RHW, THHW, THW, THWN, XHHW, USE, ZW |
Types: TBS, SA, SIS, FEP, FEPB, MI, RHH, RHW-2 THHN, THHW, THW-2, THWN-2 USE-2, XHH, XHHW, XHHW-2, ZW-2 |
Types: TW, UF |
Types: RHW, THHW, THW, THWN, XHHW, USE |
Types: TBS, SA, SIS, THHN, THHW, THW-2 THWN-2, RHH, RHW-2, USE-2 XHH, XHHW XHHW-2, ZW-2 |
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| COPPER | ALUMINUM OR COPPER-CLAD ALUMINUM | |||||
| 18 | - | - | 14 | - | - | - |
| 16 | - | - | 18 | - | - | - |
| *14 | 20 | 20 | 25 | - | - | - |
| *12 | 25 | 25 | 30 | *20 | *20 | *25 |
| *10 | 30 | 35 | 40 | 25 | *30 | *35 |
| 8 | 40 | 50 | 55 | 30 | 40 | 45 |
| 6 | 55 | 65 | 75 | 40 | 50 | 60 |
| 4 | 70 | 85 | 95 | 55 | 65 | 75 |
| 3 | 85 | 100 | 110 | 65 | 75 | 85 |
| 2 | 95 | 115 | 130 | 75 | 90 | 100 |
| 1 | 110 | 130 | 150 | 85 | 100 | 115 |
| 1/0 | 125 | 150 | 170 | 100 | 120 | 135 |
| 2/0 | 145 | 175 | 195 | 115 | 135 | 150 |
| 3/0 | 165 | 200 | 225 | 130 | 155 | 175 |
| 4/0 | 195 | 230 | 260 | 150 | 180 | 205 |
| 250 | 215 | 255 | 290 | 170 | 205 | 230 |
| 300 | 240 | 285 | 320 | 190 | 230 | 255 |
| 350 | 260 | 310 | 350 | 210 | 250 | 280 |
| 400 | 280 | 335 | 380 | 225 | 270 | 305 |
| 500 | 320 | 380 | 430 | 260 | 310 | 350 |
| 600 | 355 | 420 | 475 | 285 | 340 | 385 |
| 700 | 385 | 460 | 520 | 310 | 375 | 420 |
| 750 | 400 | 475 | 535 | 320 | 385 | 435 |
| 800 | 410 | 490 | 555 | 330 | 395 | 450 |
| 900 | 435 | 520 | 585 | 355 | 425 | 480 |
| 1000 | 455 | 545 | 615 | 375 | 445 | 500 |
| 1250 | 495 | 590 | 665 | 405 | 485 | 545 |
| 1500 | 520 | 625 | 705 | 435 | 520 | 585 |
| 1750 | 545 | 650 | 735 | 455 | 545 | 615 |
| 2000 | 560 | 665 | 750 | 470 | 560 | 630 |
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Correction Factors | ||||||
| Ambient
Temp (°C & °F) |
For Ambient Temperatures other than 30° C, (86° F), multiply the allowable ampacities shown above by the appropriate factor shown 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 |
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* Unless specifically permitted in other sections of the NEC, the load current rating and the overcurrent protection for these conductor types shall not exceed 15 amperes for No. 14, 20 amperes for No.12, and 30 amperes for No.10 copper; or 15 amperes for No. 12, and 25 amperes for No. 10 aluminum and copper-clad aluminum after any correction factors for ambient temperature and number of conductors have been applied. |
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