My garage has an existing NEMA 14-50 outlet connected to the breaker box via EMT conduit. The conduit only has 2 hot wires and 1 neutral (all #6 THHN), with ground being provided to the metal box via the conduit itself (the conduit is bonded to the breaker box).
I now want to replace this metal box and NEMA outlet with a Tesla EV charger, but I'm torn about how to properly ground it. The Tesla charger comes in a plastic box that can't be directly grounded via the conduit; instead, it expects a ground wire to be explicitly connected.
One easy way I can think of is keeping the existing metal box as a junction box and using it to feed the Tesla charger below it. In the junction box I'd add splices for the 2 hot #6 THHN wires + a new #10 THHN copper ground conductor bonded to the junction box itself. While I think this would work (but let me know if it won't), it's not ideal because:
- I'd need to keep 2 boxes (junction box + Tesla charger) instead of 1 which won't look as good.
- The Tesla charger will be lower on the wall than I want.
- I'm less familiar with EMT so would likely use PVC conduit between the junction box and Tesla charger, and I don't think this mix would look good (EMT --> metal box --> PVC --> Tesla charger).
Are there other approaches to make this work without looking bad?
Note that the conduit is really long and curvy, so it's not practical to try and feed another conductor through it all the way to the breaker box.
Update(2023-01-17): I've completed this project with a few changes from my original question, and posting these here for the benefit of future readers.
Position: When I started work, I realized that a) the current box is too high to comfortably host a Tesla charger and b) even if we kept the height, there isn't enough wire slack to loop them the way the Tesla charger expects.
As a result, I needed to either keep the box as a junction box and splice some new wire to cover the distance, or purchase and fish 30' of three #6/#10 AWG conductors (or 4, if I want to future-proof it with a neutral). Obviously the latter would cost a lot more time and money, so I went with keeping a j-box.
I initially planned to grab the ground from the final piece of EMT using a grounding bushing, but my Home Depot only had these in 2" (I needed 3/4"). So I hooked up a ring terminal to my #10 AWG green THHN, screwed that into my j-box, and ran it through the new conduit to the Tesla charger.
I took Harper's advice and took this opportunity to learn how to work with EMT. I'm glad I did! It was easier to cut than I expected, and the fittings generally made life easy.
Here's what the final product looked like: