I purchased a used Roadster about a month ago, which came with the wall unit that will go in my garage someday, but I'm still working on getting the garage built and don't really want to install the wall unit outdoors. To bridge the gap, I put in a NEMA 14-50 and bought a UMC and thought my problem was solved. But the UMC turned out to be faulty, and apparently it's not easy to get a replacement, they are "back-ordered" and I don't know when they will become available again. So currenly I'm living on a 110 outlet. Not so much fun. So I am looking for anyone who has a Roadster UMC that they are willing to sell, or willing to loan to me until Tesla is able to replace the UMC I bought with a good one, or until I get my garage built and wall unit installed, whichever comes first. Email me at rmacchi1 at tampabay.rr dot com
If you get desperate, there are EVSE's that you can buy that's not "hard-wired" into the panel. Portable, almost. So it'll connect to your NEMA 14-50 outlet with J1772 connector (hopefully you have an adapter, if not, I highly recommend the CAN). You'll be limited to 30amps.
Double check your 14-50 socket to be sure the ground (round) socket is actually grounded. The UMC will not work unless the ground connection is actually grounded. Many electrical devices use the neutral connection for grounding. For some people, the easiest way to check for this problem is to try the UMC in an RV park.
Thanks for the advice Jackyche and pgwoosley. Jackyche: I've gotten a couple nibbles already, so looks like I'll be able get my hands on a used UMC quicker than waiting for Tesla to find one, so don't need an alternate route (whatever an EVSE is??). pgwoosley: I verified the outlet is fine, by using it for the Model S. Brought the bum cable down to Tesla Service Center and they verified that it was definitely the cable, unfortunately they didn't have one to replace it with. They had already traded out the good cable they had for someone else's bad cable that only works for 10 minutes then stops charging, but it was at least available and sufficient to use for doing our troubleshooting.