EV chargers are one of the highest-draw appliances in a home. A Level 2 charger on a 50A circuit draws more power than most other household appliances. Proper wire sizing is critical for safety and charging speed.
Level 1 (120V, 12A): Uses a standard 20A outlet — 12 AWG on existing circuit. Level 2 (240V, 30-50A): Dedicated circuit required — 10 AWG for 30A, 8 AWG for 40A, 6 AWG for 50A. Level 2 (240V, 60-80A circuits): for 48A chargers such as the Tesla Wall Connector (60A circuit) or higher-power units — 6 AWG THHN with 75°C terminations or 4 AWG NM-B for 60A, 3 AWG copper for 80A.
NEC Article 625 requires that EV charger circuits be sized at 125% of the continuous load. A 40A charger needs a 50A breaker and wire rated for 50A. This means 6 AWG copper (rated 65A at 75°C). The charger must be on a dedicated circuit — no other loads on the same breaker.
Many EV chargers are installed in detached garages, requiring long wire runs. For a 50-foot run at 40A (240V), 6 AWG copper drops about 2.0V (0.8%), well within limits. Even at 100 feet the drop is about 1.6%; upsizing to 4 AWG mainly matters beyond roughly 180 feet, or where you plan a larger charger later.
If budget allows, install a 60A circuit even if your current charger only needs 40A. EV battery sizes keep growing, and faster Level 2 chargers are becoming common. Running 6 AWG or 4 AWG now avoids having to re-wire later. Also consider installing conduit rather than direct wiring, which allows future upgrades without opening walls.
Disclaimer: This guide is for informational purposes only. Always consult a licensed electrician and follow local building codes for actual installations. Wire sizing depends on specific conditions including ambient temperature, conduit fill, and derating factors.
Level 1 uses a standard 120V, 15A or 20A outlet — no special wiring needed, adds 3–5 miles of range per hour. Level 2 uses 240V, 30–60A circuits and adds 15–30+ miles per hour. Level 2 requires a dedicated EVSE (Electric Vehicle Supply Equipment) and proper circuit wiring.
EV chargers are continuous loads (NEC 625.42). The circuit must be rated at 125% of the EVSE rated current. A 48A EVSE needs a 60A circuit with 4 AWG copper; a 32A EVSE needs a 40A circuit with 8 AWG copper; a 24A EVSE needs a 30A circuit with 10 AWG copper.
A 60A circuit is recommended for most Level 2 EV chargers. It supports 48A chargers (the maximum for most EVSEs) and future-proofs your installation. A 50A circuit only supports up to 40A continuous (80% of 50A). The extra cost difference between 6 AWG (50A) and 4 AWG (60A) is modest.
Yes — most jurisdictions require an electrical permit for Level 2 EVSE circuit installation. The circuit must be inspected and meet NEC Article 625 requirements. Some utilities offer rebates for permitted EV charger installations. Unpermitted wiring may void homeowner's insurance for related fire claims.