Ampacities of Insulated Conductors (From NEC Table 310-16) | |||||||
Not More than Three Conductors in Raceway or Cable or Earth (Directly Buried) | |||||||
(Based on Ambient Temperature of 30° C, 86° F) | |||||||
Size | Copper Conductors | Aluminum Conductors | |||||
Copper-Clad Conductors | |||||||
60° C | 75° C | 90° C | 60° C | 75° C | 90° C | ||
(140° F) | (167° F) | (194° F) | (140° F) | (167° F) | (194° F) | ||
AWG | Types | Types | Types | Types | Types | Types | |
Kcil | TW | RHW | TBS | TW | RHW | TBS | |
| UF | THW | SA | UF | THHW | SA, SIS | |
| THWN | SIS | THW | THHN, THHW | |||
| XHHW | FEP | THWN | THW-2 | |||
| USE | FEPB | XHHW | THWN-2 | |||
| ZW | RHH | USE | RHH, RHW-2 | |||
| THHN | USE-2 | |||||
| THWN | XHH, XHHW | |||||
XHHW | XHHW-2, ZW-2 | ||||||
18 | – | – | 14 | – | – | – | |
16 | – | – | 18 | – | – | – | |
14 1 | 20 | 20 | 25 | – | – | – | |
12 1 | 25 | 25 | 30 | 20 1 | 20 1 | 25 1 | |
10 1 | 30 | 35 | 40 | 25 | 30 1 | 35 1 | |
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 | |
0 | 125 | 150 | 170 | 100 | 120 | 135 | |
00 | 145 | 175 | 195 | 115 | 135 | 150 | |
000 | 165 | 200 | 225 | 130 | 155 | 175 | |
0000 | 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 | |
Correction Factors for Ambient Temperature | |||||||
Ambient Temperature | For Ambient Temperatures Over 30° C, 86° F, multiply the ampacities shown above by the appropriate factor show below: | ||||||
21-25 C, | 1.08 | 1.05 | 1.04 | 1.08 | 1.05 | 1.04 | |
70-77 F | |||||||
26-30 C, | 1 | 1 | 1 | 1 | 1 | 1 | |
78-86 F | |||||||
31-35 C, | 0.91 | 0.94 | 0.96 | 0.91 | 0.94 | 0.96 | |
87-95 F | |||||||
36-40 C, | 0.82 | 0.88 | 0.91 | 0.82 | 0.88 | 0.91 | |
96-104 F | |||||||
41-45 C, | 0.71 | 0.82 | 0.87 | 0.71 | 0.82 | 0.87 | |
105-113 F | |||||||
46-50 C, | 0.58 | 0.75 | 0.82 | 0.58 | 0.75 | 0.82 | |
114-122 F | |||||||
51-55 C, | 0.41 | 0.67 | 0.76 | 0.41 | 0.67 | 0.76 | |
123-131 F | |||||||
56-60 C, | – | 0.58 | 0.71 | – | 0.58 | 0.71 | |
132-140 F | |||||||
61-70 C, | – | 0.33 | 0.58 | – | 0.33 | 0.58 | |
141-158 F | |||||||
71-80 C, | – | – | 0.41 | – | – | 0.41 | |
159-176 F | |||||||
1 The 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. | |||||||
References: To buy NEC National Electric Code books go to World Wide Web “nfpa.org”