Wire Size for 20 Amp Circuit at 50 Feet
Official National Electrical Code (NEC) sizing recommendation for a 20 Amp breaker over a 50-foot one-way conduit run on a 240V supply circuit.
Full Installation & Conduit Specifications
Interactive CalculatorCode Compliant: Voltage Drop is Within Safe Tolerance (1.61%)
At 50 feet under a 20A load, standard #12 AWG copper conductors experience only a 1.61% voltage reduction. No wire gauge upsizing is required.
Frequently Asked Technical Questions
What size copper wire is required for a 20 amp breaker at 50 feet?
For a 20 amp circuit at 50 feet on a 240V system, standard #12 AWG copper wire is sufficient. The calculated voltage drop is only 1.61%, well within the NEC recommended 3% limit.
Can I use aluminum wire for 20 amps at 50 feet?
Yes, you can use aluminum or copper-clad aluminum wiring. For 20A at 50ft, you will need #10 AWG aluminum conductors with terminals rated AL7CU or AL9CU and anti-oxidant paste where required.
What is the maximum continuous load permitted on a 20 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 20A breaker, your maximum continuous draw is 16.0 Amps.
What size conduit is recommended for this 50 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 1/2" EMT or Schedule 40 PVC.