NEC Article 625 EVSE Circuit Design: A Deep Dive
The Short Answer
NEC Article 625 governs all EVSE (Electric Vehicle Supply Equipment) installations and classifies EV charger loads as continuous — meaning conductors and overcurrent protection must be sized at 125% of the EVSE nameplate amperage. A 48 A Level 2 charger, for example, requires a 60 A circuit with 6 AWG conductors minimum.
NEC Article 625 is the governing code section for every EVSE installation in the United States. Understanding it at the circuit level — not just the summary — is what separates compliant, inspection-ready work from costly rework.
NEC 625 classifies EVSE loads as continuous (operating for 3+ hours). Branch circuits must be rated at 125% of the EVSE's maximum load current. Conductors, breakers, and outlets must all meet that 125% threshold. Additionally, 625.54 requires GFCI protection for all receptacle-based EVSE, and 625.52 mandates listed equipment.
Why EVSE Is a Continuous Load
NEC 100 defines a continuous load as one where maximum current is expected to continue for three hours or more. EV charging sessions routinely run overnight — 8 to 12 hours. That means every EVSE circuit must follow the 125% rule found in NEC 210.19(A)(1) and 215.2(A)(1): the overcurrent device and conductors must carry 125% of the EVSE nameplate ampere rating.
Circuit Sizing Table by EVSE Output
| EVSE Output (A) | 125% Value (A) | Minimum Breaker (A) | Min. Conductor (AWG Cu) |
|---|---|---|---|
| 16 A (3.8 kW) | 20 A | 20 A | 12 AWG |
| 24 A (5.8 kW) | 30 A | 30 A | 10 AWG |
| 32 A (7.7 kW) | 40 A | 40 A | 8 AWG |
| 40 A (9.6 kW) | 50 A | 50 A | 6 AWG |
| 48 A (11.5 kW) | 60 A | 60 A | 6 AWG |
| 80 A (19.2 kW) | 100 A | 100 A | 3 AWG |
Conductor Ampacity vs. Breaker Size
Always verify conductor ampacity at the actual installation temperature rating and conduit fill. A 6 AWG THWN-2 at 75 °C has a 65 A ampacity — which clears a 60 A breaker. Derate for conduit fill and ambient temperature per NEC 310.15 before finalizing wire size.
NEC 625.40: Branch-Circuit Rating
Section 625.40 states the branch circuit supplying EVSE must have a rating not less than the EVSE's rating and not less than 40 A for Level 2 equipment. This means even a 32 A charger technically sits on a 40 A circuit when following 625.40 in conjunction with the 125% continuous-load rule — confirming the 8 AWG / 40 A combination as the practical minimum for most residential Level 2 installs.
GFCI Requirements Under 625.54
NEC 625.54 requires GFCI protection for all receptacle outlets supplying EVSE. Hardwired EVSE units typically have internal ground-fault protection built into the listed unit. If you are installing a 14-50 or 6-50 outlet for a portable EVSE cord-set, a GFCI breaker is required — a standard GFCI outlet is not rated for the ampacity involved.
Equipment Listing: 625.52
- All EVSE must be listed (UL 2594 for Level 1/2 equipment)
- DC fast chargers (DCFC) are covered under UL 2202
- Unlisted equipment cannot be approved by the AHJ under NEC 625.52
- Cord sets and connectors must also carry applicable listing marks
Disconnecting Means: 625.43
NEC 625.43 requires a disconnecting means for each EVSE. For hardwired units, the branch-circuit breaker in the panel serves as the disconnect provided it is within sight or lockable. Commercial installations often require a local lockable disconnect adjacent to the EVSE — verify with your AHJ.
Always Confirm With Your AHJ
Local amendments can add requirements beyond the base NEC. Some jurisdictions require conduit for all EVSE wiring, specific connector types, or load management controls. Pull a permit and call your inspector — it protects you and the customer.
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Frequently Asked Questions
Does NEC 625 apply to Tesla Wall Connectors?
Yes. The Tesla Wall Connector is EVSE and is subject to NEC Article 625. It must be listed equipment, installed on a properly sized continuous-load circuit, with GFCI protection if supplied via a receptacle.
Can I use a 50 A breaker for a 48 A EV charger?
No. A 48 A EVSE load requires 125% sizing: 48 × 1.25 = 60 A. You need a 60 A breaker and conductors rated for at least 60 A — typically 6 AWG Cu THWN-2.
Is a GFCI breaker required for a hardwired Level 2 charger?
NEC 625.54 mandates GFCI for receptacle-supplied EVSE. Listed hardwired units typically include internal ground-fault protection that satisfies the code. Confirm with the manufacturer's installation manual and your AHJ.
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Texas Master Electrician with 12+ years in the trade and 500+ EV charger installations. Lead instructor at EVCharger Academy.
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