I want to wire a dedicated plugin to the front of my garage for a new EV, which at the moment needs to be 120. But later, I may upgrade to a 240 based charger.
Is there a suggested way I could wire this up to give myself flexibility in the future to convert to 240 without running new wire? Like run 3 (hot -hot - ground) and just use one hot for now, and the second later for 220?
Run a /3 cable (hot, hot, neutral, ground) to the receptacle location. For 110, you cap off a hot, and use the other hot, the neutral, and the ground for the receptacle. For 220, you can cap off the neutral and have 2 hots and a ground for a NEMA 6. If you want 110 & 220 together at some point, you can then land all four wires on a NEMA 14.
I'd run this circuit using 6/3 by the way -- that allows you to have anything up to a NEMA 14-50 there with an appropriate breaker to match.
There are three possible wiring modes in North American split-phase wiring:
Note the same /2 cable is used in both of the first examples. Just the white wire is marked with tape to mark it as a "hot", and the wires are landed on a 240V breaker not a 120V. So if you are 100% confident that your future 240V chargers will be 240V-only, you could get away with /2 cable.
Unfortunately I am aware that some chargers are not. I don't know what's wrong with those builders, the bits they need 120V for could easily be made to work on 240V, and then the charger could be marketed worldwide. SMH...
You could bring out 6/3 cable out to a subpanel, giving you 240/120V split at the subpanel. Very standard stuff. Then, add a breaker and receptacle for whcihever charger you get, when you get it. The general idea is, you're only going to be charging one EV at a time. So if you have a 30A charger and a 50A charger, you only need to provision 50A of service, not 80A.
The same logic applies when bringing power out to a single RV parking/camp site. You can provision all of 240/50, 240/30, 120/30 and 120/20, knowing that an RV will only use one of them at a time.
