Is this a 6-20R socket?

A 6-20P (Plug) is a thing that fits into a 6-20R (Receptacle). Which end are you looking for?

 

To be honest, the photo in post #1 looks to me more like a run-of-the-mill 5-20 (as typically used at 120 volts).

 

A 6-20 receptacle will have the right blade slot horizontal when the ground plug is at the bottom. What you have is a 5-20 receptacle. They are different so that someone doesn't plug a 120V appliance into a 250V receptacle. Too bad they didn't make them more distinct so that you could tell the difference just by looking at them.

 

Bumping the contrast on your charger plug, you can just barely make out the NEMA 6-20 up at the top. It sure didn't get stamped very sharply.



That receptacle in the wall is a 5-20. You can see the various NEMA shapes here.

Kind of funny that an electrician would mix them up.

 

Some additional input from someone who did this for a living even though the previous is all good stuff, @Darien Day. I suspect that your electrician might not be very experienced or maybe is a little sloppy since he was confused about your outlet. At a glance, the "T" shaped horizontal slot is a dead give away that it's 120V. (Edited to fix the brain fart that's crossed out above. Don't know why I did that. I know better. But it shows how easy it is to get those two things mixed up.)

The receptacle in your first picture is a 5-20R (for receptacle) which is a 120 volt, 20 amp receptacle. It has one hot wire, one neutral, and one ground.

The plug on your EVSE is a 6-20P (for plug) which is a 240 volt, 20 amp plug. It connects to two hot wires (that's how you get 240V) and one ground. That's why the blades and slots are opposite on the 5-20 and the 6-20. In many cases, you wouldn't want to plug into the wrong voltage.

Also, there is no such thing as a 16A outlet and I've never seen or heard of a 16A breaker. What you need at minimum is a 20A breaker, 14/2 with ground Romex cable, and a 6-20R receptacle. For mine, I went with 12/2 with ground, a 30A breaker and a 10-30R receptacle since my EVSE has a 10-30P plug on it. In fact, many people like to really future proof it by putting in 50A wiring which would be 8/2 with ground. It won't help with your Prime, but it'll save time & money for when you eventually get an EV and want to charge faster.

Edit to add: a big reason I upsized my wires and breaker aside from matching the plug is that breakers should not be asked to carry more than 80% of their rating for extended times. 16A on a 20A breaker is right at the limit. A 30A capacity will probably last longer.

 

It seems, according to this chart, that a 6-20R also has one T-shaped slot. The biggest difference between it and a 5-20 is the orientation of the slot that's across from the T-shaped one.

 

Exactly. It's so stinkin' easy to switch those differences in your head, especially when your fingers get going faster than your old brain. Both have the "T" but the 240V has a horizontal slot on the opposite side rather than vertical. I'll fix my boo boo. Thanks got catching that in time.