Wire Sizing
NEC charts, breaker sizing, voltage drop
| AWG | 60°C TW | 75°C THW | 90°C THHN | Typical Use |
|---|---|---|---|---|
| 14 | 15A | 15A | 15A | Thermostats, controls |
| 12 | 20A | 20A | 20A | Small window units, 1-1.5 ton |
| 10 | 30A | 30A | 30A | 2-3 ton AC units |
| 8 | 40A | 50A | 55A | 3-5 ton AC, heat pumps |
| 6 | 55A | 65A | 75A | 5+ ton, large heat pumps |
| 4 | 70A | 85A | 95A | Large commercial units |
| 3 | 85A | 100A | 115A | Large commercial |
| 2 | 95A | 115A | 130A | Large commercial |
| 1 | 110A | 130A | 145A | Large commercial |
| 1/0 | 125A | 150A | 170A | Large commercial |
| 2/0 | 145A | 175A | 195A | Heavy commercial |
| 3/0 | 165A | 200A | 225A | Heavy commercial |
| 4/0 | 195A | 230A | 260A | Heavy commercial |
75°C (THW/THWN) is the most commonly used column for HVAC installations. NEC Table 310.16, copper conductors. Always verify with local codes.