Charger fail melted connector tripped circuit

Has anyone else had a problem with the standard portable home charger that came with the 2017 i3 in US? We mostly charge overnight in the garage, and one morning the charger failed and singed the outlet. BMW service blamed the house. and said to just replace the plug and it'll be fine. Electrician replaced; blew again. The car will take charge from other sources. Is this common/normal?

A singed outlet could be due to a short-circuited Occasional Use Cable (OUC) (the charger is part of the car) or a bad outlet (fairly common). An old outlet can have corroded electrical contacts, weak grip of the plug, or corrosion where the power wires connect to the outlet. Most household circuits are rated at 15 A with a maximum continuous current of 12 A. When your AC Level 1 charging power is set to "Maximum" in iDrive, the charging circuit is passing nearly its maximum rated current, so any corrosion or problem that increases electrical resistance could generate enough heat to singe or melt an outlet and/or plug.

A circuit breaker can trip if the charging circuit is shared by some other electrical load such that the total circuit current exceeds the circuit breaker's rating. You could try charging with the AC Level 1 charging power set to "Reduced" to test whether that would prevent the circuit breaker from tripping. If not, your OUC might be defective and should be replaced by BMW under warranty.

If possible, plug your OUC into a different circuit with no shared electrical loads to see whether it would charge. If so, your charging circuit is might be overloaded or might need a new hospital-grade outlet.

Thanks, Art. The electrician is installing new GFI tomorrow and will check the loads.

FWIW, while code requires a GFCI in many locations today including a garage and outdoors (and kitchens and bathrooms, etc.!), all EVSEs have that logic built into them. It is self resetting, though as opposed to requiring a manual reset like the receptacles.

As mentioned above, though, the most common overheating problem is either a worn out receptacle (did the plug slip easily in, or did it take some force?), or loose or corroded supply connections. You're dealing with a fairly large, continuous power draw. Any loose or corroded connection acts like a resistive heating element that generates heat. Leave it long enough, and things can get messy. Once that happens, things can short out internally in the receptacle, that has nothing to do with the EVSE (OUC) unit and would happen with anything else plugged in there.

Unless you've changed them, the typical receptacles installed in a home in the USA are about the cheapest ones available. One rated industrial (would look the same) will have bigger contacts and will last longer. The things DO wear out. When it's easy to slide the plug in, it's time to replace them. It should take some force, and hold the plug easily in place.

Thank you, Jim. That's very helpful.

Make sure they use the screw on connections on the outlet and not the "stab" connections. Ideally you would have a 20 amp circuit in the garage (required by code in my area, but NEC only requires 15 A)

Check for any damage to the plug on your 120 V EVSE as well.

Thank you all. We did replace the damaged plug on the EVSE, replaced the GFI and connection box with a industrial quality, and checked that all parts are working now.

Great! When it gets near the end of a charge pull the plug and make sure the contacts aren't hot (they will be warm).

Good idea; I'll do that. Thanks!