Wait, so off topic, but I keep getting errors when trying to charge at 40 amps with my UMC. First 18 months, no problem. Next six, it kept dropping to 35 amps, now I’m down to 30 amps. If I bump it up, the next morning I have charging errors and it charged at 30 Amps. All upstream is solid.
Of course, Tesla says it’s OK.
So I’ve worn out the UMC?
People often see the UMC as a charger, but it isn't. It's an EVSE (Electric Vehicle Supply Equipment). An EVSE is in reality just a fancy relay. Not much different then a wallswitch. Only here it is the car that asks the EVSE to flip the switch. Also, an EVSE can tell the car what the max. charge rate is (the max. amps drawn). But in the end, the EVSE just supplies power. It's not a charger, the charger is in the car.
Usually when UMC throw errors its because it sees things it shouldn't see. This can be overheating but more likely it are power fluctuations. When you draw more power then the outlet can supply you will see the voltage drop. For this reason the UMC throws an error and asks the car to stop charging because voltage drops are signs of issues with the power supply.
So chances you 'worn out' the umc are very small since the UMC only does measurements and switch the switch to supply power to the car. I would put my money on grid issues. Either your grid cannot supply the amount of power you draw or it is an issue with the circuit your UMC is connected to. could be a bad connection somewhere, bad plug if the UMC doesn't have a fixed connection, etc, etc.
You should be able to read from the UMC what the error is. Different errors throw different LED warning lights. Manual shows what is what