NEMA 6-50 Wire Size for EV Charging

Use #6 copper (or #4 aluminum) on a 50A double-pole breaker with a #10 copper equipment ground, because a NEMA 6-50 is a 50A / 240V receptacle. The difference from a 14-50 is that a 6-50 has no neutral, so it uses 6/2 cable (two hots and a ground) instead of 6/3. #8 copper is the bare 75°C minimum for a 50A circuit, but #6 is the standard choice and is required if the run is NM-B cable, which uses the 60°C column where #8 is only rated 40A.

The neutral. A NEMA 14-50 has two hots, a neutral, and a ground (4 wires, 6/3 cable); a NEMA 6-50 has two hots and a ground only (3 wires, 6/2 cable). An EV charger is a pure 240V load and never uses the neutral, so a 6-50 gives it everything it needs while saving a conductor. Both are 50A / 240V and both cap a plug-in charger at 40A continuous. A 14-50 is more versatile for non-EV uses (RVs, welders, ranges that need 120V accessories); a 6-50 is the cleaner, cheaper choice when the outlet is only for EV charging or a welder.

40 amps continuous, the same as a 14-50. A plug-in EVSE on a 50A receptacle is limited to 80% of the circuit for a continuous load (NEC 210.21(B), 625.42), so a 6-50 tops out at 40A / 9.6 kW. To charge at 48A you need a hardwired charger on a 60A circuit, not any 50A plug.

Yes. NEC 625.54 requires GFCI protection for a cord-and-plug (receptacle-connected) EV charger, so a NEMA 6-50 feeding an EVSE must be on a 50A two-pole GFCI breaker. A hardwired charger with built-in CCID/GFCI does not need the GFCI breaker; a plug-in one on a 6-50 does.

The outlet is electrically the same 50A / 240V circuit either device would use, and the 6-50 is a common welder receptacle. But you cannot plug both in and run them at once on one circuit, and a permanently installed EV charger must be on its own individual branch circuit (NEC 625.40). A shared 6-50 works for occasional, one-at-a-time use of a plug-in welder or a plug-in EV mobile connector, not for a hardwired charger.