Maximum Ampacities for Wire

The table below displays approved ampacities of wires in conduit, raceway, cable or directly buried, based on an ambient temperature of  86°F (30°C). The NEC code allows rounding up cable ampacity to the next standard fuse or breaker size.

Wire Size	Copper Conductor Temp. Rating		Aluminum Cond. Temp. Rating
	167°F (75°C)	194°F (90°C)	167°F (75°C)	194°F (90°C)
*14	20	25	•	•
*12	25	30	20	25
*10	35	40	30	35
8	50	55	40	45
6	65	75	50	60
4	85	95	65	75
2	115	130	90	100
1	130	150	100	115
1/0	150	170	120	135
2/0	175	195	135	150
3/0	200	225	155	175
4/0	230	260	180	205

* The overcurrent protection device may not exceed 30A for 10 AWG wire, 20A for 12 AWG wire and 15A for 14 AWG wire.

 

For ambient temperatures above 86°F (30°C), multiply the approved ampacities from the table above by the correction factor listed under the insulation temperature below.

Temperature Range		75°F Insulation	90°F Insulation
31-35°C	87-95 F	0.94	0.96
36-40°C	96-104 F	0.88	0.91
41-45°C	105-113 F	0.82	0.87
46-50°C	114-122 F	0.75	0.82
51-55°C	123-131 F	0.67	0.76
56-60°C	132-140 F	0.58	0.71

 

Recommended Inverter Cable and Overcurrent Protection

The table below will help you choose your cable size and fuse or breaker size for a common inverter. Larger cables may be necessary if the distance from the inverter to the battery is greater than 10 feet (not recommended).

Inverter Voltage	Continuous Watts	Max Inverter Input (Amps)	Fuse Size (Amps)	Circuit Breaker (Amps)	Wire Size (AWG)
12-Volt	600	80	80	80	2
	800	107	110	110	2
	1000	134	200	175	2/0
	1500	200	300	250	4/0
	2400	320	400	250	4/0
	2500	334	400	250	4/0
	2800	382	400	250	4/0
	3000	400	400	250	4/0
24-Volt	600	40	50	50	8
	800	54	75	75	4
	1000	67	80	100	2
	1500	100	110	110	2/0
	2400	160	200	175	2/0
	2500	167	200	175	2/0
	3000	200	300	250	4/0
	3500	230	300	250	4/0
	4000	265	300	250	4/0
48-Volt	3000	76	110	110	2/0
	3600	90	110	110	2/0
	4000	148	200	175	2/0
	5500	185	400	250	4/0