What Size Wire for a 25 Amp Circuit Breaker? (NEC Table 310.16)
Complete Copper vs. Aluminum AWG wire size, continuous load limit (20A max), ground wire gauge, and conduit sizing for 25A circuits (Air conditioning condensers, mini-splits & small water heaters).
Direct NEC Table 310.16 Answer for 25 Amps
Common Applications for a 25A Circuit
Air conditioning condensers, mini-splits & small water heaters. Remember that under the NEC 125% continuous-load rule (NEC 210.19 & 210.20), a standard 25A breaker can only supply up to 20A 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 10 AWG to keep total line voltage drop under the NEC 3% branch-circuit recommendation. Use our Voltage Drop Calculator to check your exact footage.