I used Havpower. They are out of Maryland but cover Northern Virginia and are a Tesla approved wall charger installer. He knows all about what has to be done to ensure the wiring will be not only code compliant, but also support the max load your car can take. He's done both wall outlets for people who want to use their mobile charger and wall chargers for those who want to go that route. The owner is Jason Zawatsky (
[email protected]) and I highly recommend him (I have no financial interest, just a very satisfied customer).
For frame of reference, cost for me (my power panel was in my garage at the end away from where I wanted the charger installed) was $800. He said it was the same price for a NEMA outlet or for the wall charger, because the wiring is the same. Only difference is the device on the end. I chose to go the wall charger route because I wanted to avoid wear and tear on the mobile charger and because I am not comfortable constantly pulling/inserting a 220 volt plug that handles the kind of current we're talking about. I think premature outlet failure, overheating or arcing is a very real possibility. I found spending $500 for the wall charger/connector to be a much better solution.
Drop me a PM if you want more details or want to see my install.