Car is shorting my house out when it attempts to charge

[Adopado]

I'll see if the UMC is failing first. I did wonder about water ingress at the plug end - it's been reported before - but I've not been worried yet as I know it is supposed to be waterproof.

... status of UMC is that it is only waterproof ish ... I always ensure that mine is under cover on the occasions that I've used it.