CFLQTRO

What guage are the green and white wires in the picture? They look smaller than the red, particularly the green,

How is the box grounded?

skaven81

I'm not an electrician, but I'm pretty sure that the ground wire doesn't have to be the same size as the current-carrying wires. For example, a romex 6-ga wire has 6-ga black, white, and red cables, and a 10-ga ground wire inside.

I'm also not 100% sure that the neutral must be full-size when used in an application like this where it's just the center tap of a 220V single phase installation.

But the red and black wires definitely have to be full-size, as they're what actually carry the load on each cycle.

ThomasW

The EVSE will not really use the neutral. However, an appliance plugged in there could theoretically use the full 50 amps on 110V before the breaker triggers. So personally, I would want to have the neutral the same size as the black and red ones. I have seen the ground being smaller on many cables. But for the same reason as above, I felt better with it being the same size as well.

drcollie2

That looks like 8 gauge wire from the photo. I have 6 gauge copper on my outlet (quite a bit heavier) and the entire 60' wire run gets slightly warm to the touch when charging, so there's a pretty healthy current flow in the wire. The 6 is about $ 1 per foot more than the 8 and a lot more difficult to handle.

So glad you didn't have a fire. The breaker should have tripped. I think your installation electrician owes you an explanation.

ThomasW

The longer the run, the more important it is to use thicker wires. Mine is only 20 feet and the 6 gauge wire does not get warm when I measured with an infrared thermometer. So I can see it getting a little warm with a longer run, which is expected. Given these Amperage, I was trying to make sure everything is working well, which is why I checked the temperatures everywhere during the first few charging sessions.

​​Glad it did not start a fire for the OP. The metal box did its job to contain this event as much as possible.

theo1000

Wow! I'm really impressed your breaker did not trip. Definitely defective. I would contact the manufacturer.

I'm with everyone else that your electrician owes you an explanation. This could have easily gotten out of control. The wire look not correct (6) Gauge thickness. The wire management is a shambles, though unfortunately not unusual these days,which is what triggered the fire, yes you had a fire. The insulation failed from heating and the Black Hot grounded on the white neutral. As a DIY type I'd be embarrassed with that poor level of wire management and also why I prefer to DIY stuff as I tend to overkill things vs bare minimum. (6) Gauge wire is a real pain to work with and I suspect you will find the conduit is too small now. A complete rework would be strongly suggested.

One other suggestion. Use bare copper for grounding. You can see all the ground connections easily and it makes wire management easier IMHO.

hrc1079

Took the car to the dealer today to get checked out and told them what happened. They said this was common and had a customer with the exact same issue the other week. If the outlet is on an outside wall moisture can get in and build up over the colder months. So yeah, not their problem but $360 for a replacement power cable is absurd. That's half the cost of buying a whole new non Audi charger. They said the car will be fine, no need to do any checks on it and sent me on my way.

peterolsovsky

ok, now you persuaded me to get juice box when i get car.

lungs414

Usually that happens when the common wire is loose. That is the white wire. It MUST be tight and remain tight.

In looking at it again, a good practice is to have electrical tape around the screws, I don't see any. Very possible the black wire hit the metal inside the box when it was being plugged in. Laziness and not good practice to wrap the receptacle screws. You can almost see the black inside the box where the fault seems to have happened.
Also it looks like an 1900 extension box. I would have the wires go into a deep 1900 box through a bx connector or romex connector depending on the type of wire. It really looks like he used and existing box. Also the breaker definitely should have tripped. Hope its not a "Federal Pacific Breaker". If so change them all. There is an old joke about FP breakers. "How do you know when a FP breakers trips? ....When the fire department shows up. Not really funny though.

theo1000

And don't forget/forgive good old Zinsco either. I'm even iffy on the modern trend of Aluminium Buss bars. Too easy for things to meld and weld. I have replaced with copper buss bar panels on all my properties. Esp. with the present trend of heavier loads like Solar or EV's or Electric tank less water heaters, etc.

God! There have been ton of bankrupt shoddy electrical companies over the year's.