I bought a '19 S-Plus a few months ago, and recently realized that I could easily tap off of the 240V circuit in my laundry room and put a 240V outlet into the garage, which is adjacent. The way we drive it, charging on 120V is fine almost all of the time (especially under Covid), so it's really not worth it for me to hire an electrician, but I figured it was such an easy thing to do, I might as well spend the $50 or so for materials and do it myself. If we limit charging to 3.6 kW and make sure we're not using the dryer at the same time, the 30-amp circuit is more than adequate.
So last weekend I went to the hardware store, bought the materials, and put in the outlet with about two hours of effort. Pleased with myself, I excitedly plugged in the car, and ... nothing happened. No charging, no blinks from the charging lights or anything. After thinking about it overnight, I realized the problem probably had to do with the Nissan-supplied charger being smart enough to recognize that I had not grounded the equipment ground socket of the 4-prong outlet. My house is somewhat older, so the circuit I'm working with has two hot conductors and a ground wire, but no neutral. So when I installed the outlet, I used the ground wire as the neutral, thinking that a 240V load should have essentially zero neutral current. Of course doing that left nothing to connect the ground socket of the outlet to, which is why the charger refused to work. Duh. So next day, I ran a jumper between the ground and neutral sockets of the outlet, plugged it in, and esto-presto the car began charging at 240V.
Here, finally, is my question: I know that this is a code violation, but on the other hand, this is precisely the way that my dryer has been running, at almost twice the amperage and on the same circuit, for over 20 years without a problem--and there is no code violation in the way the dryer is wired (it uses a 3-prong plug/outlet). Am I making a mistake here or creating an actual hazard? Should I de-energize the outlet and go back to 120V?