Ampacity Lookup Tables

NEC Article 310.16 ampacity values with temperature derating and conductor adjustment factors.

Quick Presets

Wire Size

Material

Wire Type

Ambient Temperature (°C)

Current-Carrying Conductors

NEC 310.16

Temp Correction: 100%

Conductor Derating: 100%

Wire Type: THHN (90°C rated)

Wire Size	60°C	75°C	90°C	Adjusted Ampacity
14 AWG	15	20	25	25
12 AWG	20	25	30	30
10 AWG	30	35	40	40
8 AWG	40	50	55	55
6 AWG	55	65	75	75
4 AWG	70	85	95	95
3 AWG	85	100	115	115
2 AWG	95	115	130	130
1 AWG	110	130	150	150
1/0 AWG	125	150	170	170
2/0 AWG	145	175	195	195
3/0 AWG	165	200	225	225
4/0 AWG	195	230	260	260
250 kcmil	215	255	290	290
300 kcmil	240	285	320	320
350 kcmil	260	310	350	350
400 kcmil	280	335	380	380
500 kcmil	320	380	430	430
600 kcmil	350	420	475	475
700 kcmil	385	460	520	520
750 kcmil	400	475	535	535
800 kcmil	410	490	555	555
900 kcmil	435	520	585	585
1000 kcmil	455	545	615	615

Important Notes:

• Values shown are from NEC Table 310.16 for copper and aluminum conductors
• Adjusted ampacity includes temperature correction and conductor bundling derating
• Always verify with local code requirements and engineering calculations
• For circuits with continuous loads, apply 125% factor (NEC 210.19(A)(1))
• 14 AWG aluminum conductors are not permitted for branch circuits