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NEC Table 310.16

Complete Conductor Ampacities Reference (2023 Edition)

Standard

NFPA 70

Article

310.16

Temperature Range

60 °C - 90 °C

Critical Code Requirements

This table is based on not more than three current-carrying conductors in raceway, cable, or earth (directly buried), based on an ambient temperature of 30 °C (86 °F). Adjustments required for different conditions.

Complete Ampacity Table - Copper & Aluminum

AWG/kcmil	Copper			Aluminum/Copper-Clad
AWG/kcmil	60 °C	75 °C	90 °C	60 °C	75 °C	90 °C
18 AWG	—	—	14	—	—	—
16 AWG	—	—	18	—	—	—
14 AWG	15	20	25	—	—	—
12 AWG	20	25	30	15	20	25
10 AWG	30	35	40	25	30	35
8 AWG	40	50	55	35	40	45
6 AWG	55	65	75	40	50	55
4 AWG	70	85	95	55	65	75
3 AWG	85	100	115	65	75	85
2 AWG	95	115	130	75	90	100
1 AWG	110	130	145	85	100	115
1/0 AWG	125	150	170	100	120	135
2/0 AWG	145	175	195	115	135	150
3/0 AWG	165	200	225	130	155	175
4/0 AWG	195	230	260	150	180	205
250 kcmil	215	255	290	170	205	230
300 kcmil	240	285	320	195	230	260
350 kcmil	260	310	350	210	250	280
400 kcmil	280	335	380	225	270	305
500 kcmil	320	380	430	260	310	350
600 kcmil	350	420	475	285	340	385
700 kcmil	385	460	520	315	375	425
750 kcmil	400	475	535	320	385	435
800 kcmil	410	490	555	330	395	445
900 kcmil	435	520	585	355	425	480
1000 kcmil	455	545	615	375	445	500
1250 kcmil	495	590	665	405	485	545
1500 kcmil	525	625	705	435	520	585
1750 kcmil	545	650	735	455	545	615
2000 kcmil	555	665	750	470	560	630

Temperature Correction Factors

Ambient Temperature	60 °C	75 °C	90 °C
10 °C or less (50 °F or less)	1.29	1.20	1.15
11–15 °C (51–59 °F)	1.22	1.15	1.12
16–20 °C (60–68 °F)	1.15	1.11	1.08
21–25 °C (69–77 °F)	1.08	1.05	1.04
26–30 °C (78–86 °F)(Standard)	1.00	1.00	1.00
31–35 °C (87–95 °F)	0.91	0.94	0.96
36–40 °C (96–104 °F)	0.82	0.88	0.91
41–45 °C (105–113 °F)	0.71	0.82	0.87
46–50 °C (114–122 °F)	0.58	0.75	0.82
51–55 °C (123–131 °F)	0.41	0.67	0.76
56–60 °C (132–140 °F)	—	0.58	0.71
61–65 °C (141–149 °F)	—	0.47	0.65
66–70 °C (150–158 °F)	—	0.33	0.58
71–75 °C (159–167 °F)	—	—	0.50
76–80 °C (168–176 °F)	—	—	0.41
81–85 °C (177–185 °F)	—	—	0.29

Example: 12 AWG copper at 75 °C = 25 A. In 40 °C ambient: 25 A × 0.88 = 22 A adjusted ampacity

Conductor Bundle Adjustment Factors

Current-Carrying Conductors

Number of Conductors	Adjustment Factor
1-3	1.00
4-6	0.8
7-9	0.7
10-20	0.5
21-30	0.45
31-40	0.4
41+	0.35

Common Circuit Applications

Circuit Type	Copper Wire	Aluminum Wire	Common Uses
15 A General Purpose	14 AWG	12 AWG	Lighting, receptacles
20 A Kitchen/Bath	12 AWG	10 AWG	Small appliances, bathroom
200 A Dwelling Service (Table 310.12)	2/0 AWG	4/0 AWG	Main service entrance

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Important Notes & Exceptions

When NOT to Use This Table

Conductors in free air (use Table 310.17)
Bare or covered conductors (use Table 310.21)
Underground installations with specific conditions

How to Read and Apply NEC Table 310.16 — End-to-End

Anatomy of NEC Table 310.16 — six columns, one row per AWG

The table organizes ampacities by conductor material (copper or aluminum) and insulation temperature class (60 °C, 75 °C, or 90 °C).

NEC 310.16 only sets ampacity — overcurrent protection is a separate calculation

The output of NEC 310.16 (after all derating) is the maximum continuous current the conductor can carry. It is NOT the breaker size. To pick the breaker:

NEC 240.4(D) — small-conductor rule caps OCPD at 15/20/30 A for 14/12/10 AWG copper.
NEC Table 240.6(A) — standard breaker sizes are 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, 6000.