Wire Gauge Amp Capacity Lookup
NEC 310.15 ampacity tables, wire sizing calculator, and voltage drop calculator for copper and aluminum conductors.
Select parameters
Find minimum wire gauge for your load
Common applications
Lighting / outlets
14 AWG
15A load
Kitchen / bathroom
12 AWG
20A load
Dryer / A/C
10 AWG
30A load
Range / EV charger
8 AWG
40A load
Large A/C / subpanel
6 AWG
60A load
200A main service
4/0 AWG
200A load
Ampacity table — copper, in conduit
| Gauge | Ampacity | Max breaker | Ω/1000ft | Diameter | Common use |
|---|---|---|---|---|---|
| 14 AWG | 15A | 15A | 3.140 | 0.064" | Lighting, outlets (15A circuits) |
| 12 AWG | 20A | 20A | 1.980 | 0.081" | Kitchen, bathroom (20A circuits) |
| 10 AWG | 30A | 30A | 1.240 | 0.102" | Dryers, A/C, water heaters |
| 8 AWG | 40A | 40A | 0.778 | 0.128" | Ranges, EV chargers, hot tubs |
| 6 AWG | 55A | 60A | 0.491 | 0.162" | Subpanels, large A/C |
| 4 AWG | 70A | 70A | 0.308 | 0.204" | Large subpanels, EV fast charge |
| 3 AWG | 85A | 90A | 0.245 | 0.229" | Feeders |
| 2 AWG | 95A | 100A | 0.194 | 0.258" | 100A service feeders |
| 1 AWG | 110A | 110A | 0.154 | 0.289" | Feeders, large subpanels |
| 1/0 AWG | 125A | 125A | 0.122 | 0.325" | 125A service, large feeders |
| 2/0 AWG | 145A | 150A | 0.097 | 0.365" | 150A service |
| 3/0 AWG | 165A | 175A | 0.077 | 0.41" | 175–200A service |
| 4/0 AWG | 195A | 200A | 0.061 | 0.46" | 200A main service |
| 250 kcmil | 215A | 225A | 0.051 | 0.52" | 225A service |
| 300 kcmil | 240A | 250A | 0.043 | 0.57" | Large commercial feeders |
| 350 kcmil | 260A | 300A | 0.037 | 0.616" | Large commercial feeders |
| 400 kcmil | 280A | 300A | 0.032 | 0.659" | Large commercial feeders |
| 500 kcmil | 320A | 400A | 0.026 | 0.736" | 400A+ service, large commercial |
NEC 310.15 reference notes
Ampacity values are based on NEC Table 310.15(B)(16) at 60°C/75°C conductor temperature rating in 30°C ambient. For ambient temperatures above 30°C or more than 3 current-carrying conductors in a conduit, apply correction and adjustment factors per NEC 310.15(B). Continuous loads require conductors sized at 125% of the load. Always consult a licensed electrician for final design decisions.
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