What is this outlet in my garage and can I charge an EV from it?

Question

The previous owner had a workshop in the garage supplied with lots of electrical outlets, including this one. Can I use it to charge an electric car?

I believe this is the circuit breaker for it.

Answer 1

Welders are very different loads

An EV is the hardest "hard load" ever seen on home electric. It runs at full nameplate ampacity continuously for hours. As such any EV circuit needs to be tip-top.

In fact EV charging is only allowed to run at 80% of breaker trip. So you get 3840W (4kW) out of a 20A circuit.

Welders are the exact opposite - they draw only while they are going FLASH-BZZZT, and hobby/home welding does that at an extremely low duty cycle (percent time on vs percent time off). Code allows for that, so really weird combinations of sockets and breakers are perfectly normal for welders.

DO NOT obtain a NEMA 6-50 dongle for your travel EVSE and slap it into this socket. The dongle will tell your EV "you're all good to pull 40A all night" and we don't want that.

(The EVSE isn't a charger; it's a gateway whose job is to tell the car the safe amps available, and also be a GFCI. The charger is inside the car, the size of a suitcase and water-cooled.)

You probably don't need more than 20A anyway

EV charging in any home is limited by the available power. This is determined by a NEC Article 220 Load Calculation. Slapping a huge 40-60A EVSE on any random house is most likely going to overload the service.

But that's fine. Alec of the linked videos conservatively says a 20A circuit gives 100 miles of charge in 10 hours of overnight charging. (Tesla claims 150 miles actually). So in a more realistic 13 hour charge, that's 130-200 miles a night.

We like hardwired wall-unit EVSEs. They're more convenient, and for people in NEC 2020 territory you are relieved of the obligation to install a GFCI breaker, which is redundant since an EVSE is a GFCI. In that case, you'd get a blank cover plate that has a "1/2" trade size knockout hole" on it, and come out of that with flexible metal conduit to the EVSE - or simply install the EVSE directly on top of it if that's not awkward.

However if you want to use a plug-in EVSE, you can replace the NEMA 6-50 with one or two NEMA 6-20 type receptacles. As you can see, they just use normal cover plates. You might find a 2-gang box, in which case I leave it to you whether to install dual 6-20s, install a 6-20 and a "switch that does nothing", or hunt down a socket+empty cover plate.

Answer 2

The answer is yes.... but*

The outlet appears to be a NEMA 6-50 which is rated for 240V, 50A. 6-50 is a really widely-used plug for cord-and-plug connected EV supply equipment, partly because it was already popular for welding equipment.

However, the breaker is 240V 20A, which clearly does not match the receptacle. It's possible that the seller downsized the breaker to fit the welder's current requirements.

The general answer is yes - you can use that to charge an EV, even 20A is good enough for nearly all reasonable use cases.

However, in order to make the circuit code-complaint you will need to look at the wire between the breaker and the receptacle to see how much current is OK to draw on that circuit, then replace either the breaker or receptacle so they match.