@Mike, copy all, i just had an electrician come by and he said the same thing, there is nothing in NEC that talks about it and he said as long as it looks professional he didn't believe it would be an issue.
There may be nothing in the NEC specifically about this, but whatever gets installed has to be listed for such use and I really doubt UL or any other testing agency has listed a reducer as a box connector.
@Sparky, I'm trying to do it the right way as long as it meets the code and passes. I agree I would not want to redo this if I can avoid it. To answer your question yes that is the plan to put the reducer in the panel and in the charger box. I don't believe it is any larger than 1-2" in length so i hope it is not a clearance issue. I know it won't be in the panel but the charger box I don't know b/c I don't have it delivered yet.
I like to keep it as simple as possible, this to me is simple, smallest hole possible in the stucco, drywall and in between. Is there a better option than the reducer that would serve the same purpose in your opinion now that you have an idea what I'm trying to do that would pass as a box connector?
thanks again for all your guys input.
I took some measurements, but I don't have a 1" PVC male adapter on hand to check. If you use the reducer, you will have to run PVC through the wall and that's going to require a 1-3/8" hole to get the pipe through. If you use 1" EMT with a compression connector, the connector that I have would require a 1-3/4" hole to fit through. A PVC male adapter wouldn't need that large of a hole, but since I don't have one on hand, I can't tell you what it would require, but it's probably 1-5/8" or so. As far as the boxes for the chargers, 3/4" PVC will need a 1-1/8" hole. If you use the pipe with a male adapter on the end, you're going to need a 1-1/2" hole. If you were to use 3/4" EMT with a compression connector, a 1-1/2" hole would also be needed..
Remember, the connectors or male adapters are going to be fairly tight in the hole, no different that if you were to have a piece of pipe in there. Sure, the hole will be marginally larger, but it will be behind the box and nobody is going to see it.
That's really all the input I have for your original question about getting through the wall via the back of the panel, but I am going to suggest what I would do if it were my house. Come straight out of the bottom of the panel and use an LB to go through the wall. Sealing will be easy and you have enough going on at the panel that nobody will notice it. The only other thing I could suggest would be conduit around the outside to the chargers, but that may put it on display for everyone that pulls in the driveway to see and I wouldn't want that. If it were on the back of the garage only and I would be the only person to see it when I am mowing the lawn, you bet I'd run it exposed.