Maximum Current in Insulated Wire

Maximum allowed current (amps) in an insulated wire conductor with no more than three current-carrying conductors in a raceway, cable, or earth (directly buried)

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Maximum Current for Copper Wire

Wire Size Copper
60°C 75°C 90°C
TW, UF THW,
THWN,
THHW,
USE		 THHN
18 AWG* ---- ---- 14
16 AWG* ---- ---- 18
14 AWG* 15 20 25
12 AWG* 20 25 30
10 AWG* 30 35 40
8 AWG 40 50 55
6 AWG 55 65 75
4 AWG 70 85 95
3 AWG 85 100 115
2 AWG 95 115 130
1 AWG 110 130 145
1/0 AWG 125 150 170
2/0 AWG 145 175 195
3/0 AWG 165 200 225
4/0 AWG 195 230 260
250 MCM 215 255 290
300 MCM 240 285 320
350 MCM 260 310 350
400 MCM 280 335 380
500 MCM 320 380 430
600 MCM 350 420 475
700 MCM 385 460 520
750 MCM 400 475 535
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Maximum Current for Aluminum Wire

Wire Size Aluminum
60°C 75°C 90°C
TW, UF THW,
THWN,
THHW,
USE		 THHN
18 AWG* ---- ---- ----
16 AWG* ---- ---- ----
14 AWG* ---- ---- ----
12 AWG* 15 20 25
10 AWG* 25 30 35
8 AWG 35 40 45
6 AWG 40 50 55
4 AWG 55 65 75
3 AWG 65 75 85
2 AWG 75 90 100
1 AWG 85 100 115
1/0 AWG 100 120 135
2/0 AWG 115 135 150
3/0 AWG 130 155 175
4/0 AWG 150 180 205
250 MCM 170 205 230
300 MCM 195 230 260
350 MCM 210 250 280
400 MCM 225 270 305
500 MCM 260 310 350
600 MCM 285 340 385
700 MCM 315 375 425
750 MCM 320 385 435

Table 310.16, 2020 NEC®

Section 310.15(B) ( Ambient Temperature Correction Factors Based on 30°C (86°F) ) shall be referenced for ampacity correction factors when the ambient temperature is other than 30°C (86°F).

Section 310.15(C)(1) ( Adjustment Factors for More Than 3 Current Carrying Conductors) shall be referenced for more than three current-carrying conductors.

Section 310.16 shall be referenced for conditions for use.

*Section 240.4(D) shall be referenced for conductor overcurrent protection limitations, except as modified elsewhere in the Code.

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WARNING: For safety, call a licensed electrician and consult the NEC®. All licensed electricians have passed examinations covering the National Electric Code®, know state and local building codes, and may carry insurance to cover damages.