Ampacity Table

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Ampacities of Insulated Conductors

Ampacities Of Insulated Conductors
(From NEC Table 310-16)

Not more three condcutors in Raceway or Cable or Earth (Directly  Buried)

Size

Copper Conductors

Aluminum Conductors
Copper-Clad Conductors

60oC
(140o F)
75oC
(167o F)

90oC
(194oF)

60oC
(140o F)
75oC
(167o F)
90oC
(194oF)
Wire Size
(AWG
or
Kcmil)
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 - - -
141 20 20 25 - - -
121 25 25 30 201 201 251
101 30 35 40 25 301 351
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

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 Over 30oC, 86oF

Ambient Temperature

For Ambient Temperature Over 30o C, 86o F, multiply the ampacities shwon above by the appropriate factor show below:

21-25o C,
70-77o F
1.08 1.05 1.04 1.08 1.05 1.04
26-30o C,
78-86o F
1.00 1.00 1.00 1.00 1.00 1.00
31-35o C,
87-95o F
.91 .94 .96 .91 .94 .96
36-40o C,
96-104o F
.82 .88 .91 .82 .88 .91
41-45o C,
105-113o F
.71 .82 .87 .71 .82 .87
46-50o C,
114-122o F
.58 .75 .82 .58 .75 .82
51-55o C,
105-113o F
.41 .67 .76 .41 .67 .76
56-60o C,
132-140o F
- .58 .71 - .58 .71
61-70o C,
141-158o F
- .33 .58 - .33 .58
71-80o C,
159-176o F
- - .41 - - .41

 

 

3-Wire residential sevices, 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

 

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