Yeah, thank you very much for tagging me into this. There is so much I have to say about this.
It's not new. That corded mobile connector has been available for a few years. It is based on the original Generation 1 mobile connector, which is why it has the capability of 40A, like those ones did. But this version has the plug permanently affixed, which is more solid than the connection method that had some trouble with the original adapters.
Oh, jeez. That is wrong and violates code. Code is absolutely clear on that, that the breaker must not be higher than the outlet rating. That is a 50A outlet type, so you must not use higher than a 50A breaker for it. You need to change that.
That's not a Gen2 mobile connector. It's the Corded Mobile Connector, which is made from the Gen1, so yes, it should be capable of working at 40A.
OK. Now we can finally get to your question.
The cars have a safety monitoring system that checks the voltage before it ramps up charging, and compares that to the voltage after it ramps up, and if there is a pretty bad voltage drop, that shows that there is probably a weak or loose connection somewhere in the circuit that is very resistive. It will then lower to 3/4 of the current setting it was trying to use. That's why it's an informative symptom that you are seeing 30 instead of 40 amps. That 3/4 ratio is what usually shows this.
So, since we already found that you were using the wrong breaker type in this DIY installation, I would obviously ask next what type and size of wire you decided to use there. Wire gauge that is too thin or not clamped/screwed in tight enough could cause this. Or we've also seen frequently where the ends of the wire were stripped a little, but where they were pushed into the terminals of the outlet, some of the plastic insulation got in under the screw, so it's preventing solid metal to metal connection there, and you can get a very hot spot that will trigger the car's safety system like that.
So, what is your wire situation?
