NEC Article 625 EV Charging
NEMA 14-50 Wire Size for EV Charging
A NEMA 14-50 is a 50-amp, 240-volt receptacle, the most common plug for a Level 2 EV charger. Here is the wire, breaker, ground, and GFCI it needs, plus the 40-amp continuous limit that catches people out.
NEMA 14-50 Circuit Spec
| Receptacle / circuit rating | 50A, 240V |
| Breaker (double-pole, GFCI) | 50A |
| Copper wire (standard) | #6 |
| Copper wire (75°C-marked terminations only) | #8 |
| Aluminum wire | #4 |
| Equipment ground (Cu) | #10 |
| Max continuous charge (plug-in) | 40A (9.6 kW) |
#6 copper covers the 50A circuit at both the 60°C and 75°C columns of NEC Table 310.16 and is the standard choice; #8 copper is the 75°C-only minimum, and it holds only where the breaker and the receptacle are both listed and marked for 75°C conductors (NEC 110.14(C)(1)(a)). Ground per NEC 250.122. GFCI per NEC 625.54. Check voltage drop on runs over about 100 feet.
Why a 14-50 Charges at 40A, Not 50A
EV charging is a continuous load (three hours or more), and NEC 210.21(B)(2) limits a continuous load on a receptacle to 80% of the circuit rating. On a 50A circuit that is 40A, so any plug-in charger on a NEMA 14-50 is set to draw 40A maximum, about 9.6 kW. This is why a 48A charger cannot run on a 14-50: 48A needs a 60A circuit, which means a hardwired connection, not a plug. If you want the full 48A / 11.5 kW, hardwire the charger.
Your Exact Run: Wire, Panel, and Parts
The calculator opens on a NEMA 14-50 outlet at 40A. The wire it shows is the 75°C THHN minimum; 6/3 NM-B cable needs #6 copper, the size quoted above. Enter your run length and panel to get the exact wire, voltage drop, panel-capacity check, GFCI note, and a parts list.
Frequently Asked Questions
What size wire for a NEMA 14-50 outlet?
Use #6 copper (or #4 aluminum) on a 50A double-pole breaker, with a #10 copper equipment ground (#8 if the ground is aluminum), because a NEMA 14-50 is a 50A / 240V receptacle. #8 copper carries 50A only at the 75°C column of NEC Table 310.16, which on a 50A circuit holds only where the breaker and the receptacle are both listed and marked for 75°C conductors (NEC 110.14(C)(1)(a)); on 60°C terminations or NM-B cable (NEC 334.80) #8 carries only 40A, so #6 is the answer that holds on any termination, and it also keeps voltage drop low. A 14-50 is a 4-wire device (two hots, a neutral, and a ground); an EV charger does not use the neutral, but the receptacle still has the terminal.
Can I use #8 wire for a NEMA 14-50?
Only on 75°C-rated terminals with conductors like THHN/THWN-2 in conduit, where #8 copper carries 50A and technically satisfies the 50A circuit. Most electricians still pull #6 for a 14-50 for margin, and #8 is not allowed if the run is NM-B (Romex), because NM-B uses the 60°C column where #8 copper is only rated 40A, below the 50A circuit. When in doubt, use #6 copper.
How many amps can an EV charger on a NEMA 14-50 draw?
40 amps continuous. A plug-in EVSE on a 50A receptacle is limited to 80% of the circuit rating for a continuous load (NEC 210.21(B)(2)), so a NEMA 14-50 tops out at 40A / 9.6 kW no matter what the car could accept. To charge at 48A you need a hardwired charger on a dedicated 60A circuit, not a 14-50 plug.
Does a NEMA 14-50 for an EV charger need a GFCI breaker?
Yes. NEC 625.54 requires GFCI protection for a cord-and-plug (receptacle-connected) EV charger, so a NEMA 14-50 feeding an EVSE must be on a GFCI breaker. This is the opposite of a hardwired charger, which usually has built-in CCID/GFCI and does not need a GFCI breaker. Use a 50A two-pole GFCI breaker listed for the panel.
Does a NEMA 14-50 need a dedicated circuit?
Yes, for EV charging. The receptacle must be the only outlet on its branch circuit (an individual branch circuit) so the full 50A is available to the charger, per NEC 625.40. Sharing the circuit with other outlets is not permitted for an EVSE install.
Related EV References
40 Amp EV Charger Wire Size
The hardwired 40A charger on a 50A circuit, the amperage a 14-50 delivers.
48 Amp EV Charger Wire Size
Step up to a hardwired 60A circuit for the full 48A / 11.5 kW.
Will My Panel Handle It?
Check whether your panel has room for the 50A circuit.
EV Charger Calculator
Wire, breaker, panel, and GFCI for any EV charger install per NEC 625.