What Size Wire for a 35 Amp Circuit Breaker? (NEC Table 310.16)
Complete Copper vs. Aluminum AWG wire size, continuous load limit (28A max), ground wire gauge, and conduit sizing for 35A circuits (Heat pumps, commercial rooftop units & medium welders).
Direct NEC Table 310.16 Answer for 35 Amps
8 AWG
Minimum Copper Wire (75°C)
THHN / THWN-2 / XHHW in Conduit
6 AWG
Minimum Aluminum Wire (75°C)
SER / XHHW-2 Feeder Cable
28 Amps
Max Continuous Load (80% Rule)
For loads running 3+ hours (EVs, lighting)
3/4" EMT
Recommended Conduit Size
Fits 3x 8 AWG + Ground under 40% fill
Common Applications for a 35A Circuit
Heat pumps, commercial rooftop units & medium welders. Remember that under the NEC 125% continuous-load rule (NEC 210.19 & 210.20), a standard 35A breaker can only supply up to 28A of continuous load (any load that runs for 3 hours or more without stopping, such as an EV charger or commercial lighting).
When to Upsize for Voltage Drop (Over 100 Feet)
If your one-way wire run exceeds 100 feet at 240V (or 50 feet at 120V), step up one wire gauge from 8 AWG to keep total line voltage drop under the NEC 3% branch-circuit recommendation. Use our Voltage Drop Calculator to check your exact footage.