Finally converted a NEMA 5-20R to 6-20R and...

[Kermee]

... I absolutely love it.

I had a single 5-20R outlet on a dedicated 20A breaker in the garage that was wired with 12/2 Romex that I verified (No other receptacles on the circuit to the breaker). Thanks to @ratsbew and everyone's helpful replies in his thread Convert NEMA 5-20 to 6-20? (Much appreciated all!), I decided to do the same thing.

• Picked up a $10 2-pole 20A breaker and a $5 NEMA 6-20R socket.
• $35 for Tesla to ship me the NEMA 6-20P "dongle" for the UMC2.
• Tested the voltages on new receptacle to make sure I didn't screw anything up.
• Measured 246-248V across the hots, and 123-124V between each hot and ground.
• Plugged in the UMC2 with the new fandangle NEMA 6-20P into the outlet... And the UMC2 lit up like normal.
• Then plugged into my Tesla Model 3 AWD... Success!
• Kept watch over the next hour and everything seems to be working fine!

I seriously thought about hiring an electrician to install a dedicated NEMA 14-50R or even a hardwired Tesla HPWC, but there's enough free charging stations where I work, live and drive, I only really need to top-off at home overnight if I need to go on an extended drive, back to back. Worst case, there's a Supercharger less than 5 miles from my house. I'm pretty sure the 4kW of power will be enough for my needs. This might be one of the best solutions or options for anyone else that might have a similar setup at home. It's definitely one of the most inexpensive ones that doesn't require much work and someone could DIY.

Showing 4 kW with 246V at the full 16A limit.

About 2 more hours to charge from 80% to my set 90% limit at 4 kW.​

 

[timk225]

I did something similar, except I put in an entirely new breaker, outlet, and new dedicated 12/2 wire with "6-20 240 volt" marked on it several times along its length.

The 6-20 will charge at 15 mph, for an easy +150 miles overnight or more. I only drag out the heavy 15 foot Camco 14-50 extension cord now to use the 14-50 when the battery is way low and I need it full the next day, so once every few weeks maybe.