So I had a pre-existing 40A circuit with a Leviton 6-50 outlet with a 30A EVSE plugged into it for a previous EV. It worked fine with no problems then.
That EVSE was not very reliable for the Model 3, so I put the (then included) mobile connector with 6-50 plug adapter in it. Worked fine for a while...
But during the summer, with warmer garage temperatures, the car sometimes reduced the charge rate from 32A to 16A. The plug adapter on the mobile connector also felt quite warm while charging, although there was no melting or any other indication of damage to it or the outlet. The outlet did not seem to be that hot.
However, I tried replacing the outlet with a Bryant 6-50 outlet (ordered from Grainger, received very quickly) just to make sure it was not the outlet. This did have an unexpected problem with the Bryant 6-50 outlet being too large to fit in the existing box, so a box extension was needed. I also noticed that the Bryant 6-50 outlet has screw-down clamps (similar to the Leviton 6-50), rather than the more mistake-resistant clamping mechanism observed by others with the Hubbell or Bryant 14-50 outlet.
One thing I did notice with a careful look in the prong holes is that the Leviton 6-50 outlet contacts are smaller than those in the Bryant 6-50. This is similar to what a Youtuber has noticed with a Leviton 14-50 outlet, and may be the reason for the heat at the mobile connector's plug adapter.
However, it is still too early to tell if the outlet change fixed the issue, since the weather has not been as warm as it was before.
That EVSE was not very reliable for the Model 3, so I put the (then included) mobile connector with 6-50 plug adapter in it. Worked fine for a while...
But during the summer, with warmer garage temperatures, the car sometimes reduced the charge rate from 32A to 16A. The plug adapter on the mobile connector also felt quite warm while charging, although there was no melting or any other indication of damage to it or the outlet. The outlet did not seem to be that hot.
However, I tried replacing the outlet with a Bryant 6-50 outlet (ordered from Grainger, received very quickly) just to make sure it was not the outlet. This did have an unexpected problem with the Bryant 6-50 outlet being too large to fit in the existing box, so a box extension was needed. I also noticed that the Bryant 6-50 outlet has screw-down clamps (similar to the Leviton 6-50), rather than the more mistake-resistant clamping mechanism observed by others with the Hubbell or Bryant 14-50 outlet.
One thing I did notice with a careful look in the prong holes is that the Leviton 6-50 outlet contacts are smaller than those in the Bryant 6-50. This is similar to what a Youtuber has noticed with a Leviton 14-50 outlet, and may be the reason for the heat at the mobile connector's plug adapter.
However, it is still too early to tell if the outlet change fixed the issue, since the weather has not been as warm as it was before.