What Size Breaker for EV Charger (32A)?
A ev charger (32a) requires a 40A breaker with 8 AWG wire on a 240V dedicated circuit. This is a continuous load — breaker rated at 125% of actual draw.
🔌 Wire Length & Voltage Drop Check
EV Charger (32A) Wiring Guide — NEC Requirements
A 32A EVSE (like the Tesla Mobile Connector at full power) requires a 40A breaker (32A × 125% = 40A). This adds about 25 miles of range per hour of charging.
Pro Tip
💡 If running wire more than 50 feet, upsize to 6 AWG to keep voltage drop under 3%.
Why a 40A Breaker?
The ev charger (32a) draws approximately 32A at 240V (7680W). As a continuous load (3+ hours), NEC 210.20 requires the breaker at 125%: 32A × 1.25 = 40.0A → 40A breaker.
Wire Sizing per NEC 310.16
For a 40A/240V circuit, 8 AWG copper is required per NEC Table 310.16 at 75°C. For runs over 75 feet, upsize to 6 AWG (over 50ft). Use our Wire Size Calculator and Voltage Drop Calculator.
Complete Parts List
To wire a ev charger (32a) circuit: a 40A double-pole breaker, 8 AWG NM-B cable (Romex) for interior runs or THHN/THWN-2 in conduit for exposed runs, a NEMA 14-50 receptacle (or hardwired), cable clamps, and appropriate junction boxes.
Disclaimer: This guide is for reference only. All electrical work must be performed by or verified by a licensed electrician. Local codes may differ from NEC.