Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.

8.6kW UMC Gen 2 Charging on SR+ with 277Vac!


Jun 25, 2019
I decided to update the wiring at my work where I do most of my charging. I was using a 30A 277V circuit, with a NEMA L7-30 to NEMA 14-30 pigtail, connected to my UMC with 14-30 adapter. I was pretty happy with the speed, 6.4kW for only 24 amps is pretty good!

But that wasn't enough, plus I wanted a closer outlet, so I used relocating the outlet as an excuse to upgrade. I installed a 40 amp 277V circuit (Nema 7-50 outlet, 8AWG wiring), ordered a NEMA 6-50 adapter from Tesla (it was cheaper than the 14-50), and made a 7-50 to 6-50 pigtail adapter. Now I'm seeing 8.6kW (32A @ 269V, nice) charging on average, sometimes up to 8.9kW in the morning when line voltage regulation is at 277V. Pretty good for a SR+ which is normally quoted as 7.7kW max.

IMG_1089 2.JPG

IMG_1090 2.JPG
Last edited:

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.