Wire Size for 15 Amp Circuit at 200 Feet
Official National Electrical Code (NEC) sizing recommendation for a 15 Amp breaker over a 200-foot one-way conduit run on a 120V supply circuit.
Full Installation & Conduit Specifications
Interactive CalculatorVoltage Drop Alert: Base #14 AWG Wire Exceeds 3% (15.35%)
NEC Section 210.19(A) Informational Note 4 recommends that feeder and branch circuits maintain voltage drop under 3% (and 5% total) to protect appliances from motor burnout and voltage sagging. Using upsized #6 AWG copper wire successfully brings voltage drop back under safe limits.
Frequently Asked Technical Questions
What size copper wire is required for a 15 amp breaker at 200 feet?
Due to voltage drop over 200 feet (15.35% on base wire), the National Electrical Code (NEC) recommends upsizing copper wire from #14 AWG to #6 AWG. This keeps the voltage drop under 3%, protecting your equipment from overheating and brownout damage.
Can I use aluminum wire for 15 amps at 200 feet?
No. The NEC does not permit aluminum wiring on standard 15-amp branch circuits. You must use copper (#14 AWG or upsized).
What is the maximum continuous load permitted on a 15 amp breaker?
Per NEC Article 210.20, continuous loads (operating for 3 hours or longer, such as EV chargers or heaters) cannot exceed 80% of the breaker rating. For a 15A breaker, your maximum continuous draw is 12.0 Amps.
What size conduit is recommended for this 200 ft run?
Based on Chapter 9, Tables 1 and 4 of the NEC for up to 3-4 current-carrying conductors plus ground at a 40% maximum conduit fill, we recommend using 3/4" EMT or Schedule 40 PVC.