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Wire Ampacity Tables

   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
(140 F)
75 C
(167 F)
90 C
(194 F)
60 C
(140 F)
75 C
(167 F)
90 C
(194 F)
AWG
Kcil
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
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
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
 

   Correction Factors for Ambient Temperature Over 30 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

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.

 
   3-Wire residential services, allowable ampacities
Copper AWG Aluminum AWG Service Ampacity
4 1 100
3 1 110
2 1/0 125
1 2/0 150
1/0 3/0 172
2/0 4/0 200

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