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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|