Here's the situation: House was built in the 1980s. My laundry room has an existing NEMA 10-30 outlet that is not being used since we have a gas dryer. I am thinking about getting an electric car so I'll need a place to charge it in the garage which is located just outside the laundry room door which is just adjacent to this unused 10-30 outlet. My thought was maybe I could junction off of this outlet and run a 10 gauge Romex to the garage wall for a new outlet to plug in the car.
I was hoping to not have to run all new cable from the breaker box because that is in the basement. The breaker for this circuit a 2-pole 30 amp breaker. Since I may some day want to use this laundry room outlet if we were to get an electric dryer, I was thinking it would be nice to keep that installed as an outlet and just run new wires from that to the garage. I wasn't sure if that was acceptable and if I did this would it mean that I'd only be able to use one outlet at a time. The car can be set to pull 24 amps for the 30 amp circuit. (80% of 30 amps) As I said I don't need the outlet now but if some day I wanted to use it would this be a problem for the circuit?
My other thought is to just move the NEMA 10-30 outlet (or install a new NEMA 14-30) to the garage and use the existing outlet box as a junction box to tie-in the new cables. Then close the laundry room box up with a blank faceplate so it won't be usable anymore. I would then use the newly installed garage outlet for the car charging.
I appreciate any advice you can offer for this situation. I've relocated 120 volt outlets before for various reasons but I've never done this for a 240 so I wasn't sure if that makes a difference. I'll likely get an electrician to do the work either way but just thought I'd get some advice here on what is possible.
Thanks for the responses this has been helpful. I was not aware that the code requires EV chargers to be on a dedicated circuit so that was good to learn. Here's a few pictures I was finally able to take of the outlet wiring. I'll probably just get an electrician to add a dedicated 50 amp circuit to the garage instead and leave this one as is.
Best Answer
The good news: you have the wires you need
The good news in your situation is that you have all four wires (two hots, a neutral, and a ground) present already (which makes me wonder why the NEMA 10 receptacle was installed in the first place, but I digress). This means that this circuit can safely power a 16A EVSE with ease.
The bad news: electric car chargers can't share
The bad news is that as per NEC 625.40, electric car chargers (EVSE) require a dedicated circuit:
While this means that the circuit won't be usable for a dryer any longer, it still leaves you with two options: either you can convert the existing run into a feeder using a small "spa box" sized subpanel (and replace the dryer receptacle with a NEMA 14-30 while you're at it), or you can remove this receptacle and use the box as a splice point to start your new run of 10/3 to the garage.