We just had a air conditioner compressor installed last week. The contractor installed a new 240V 30Amp circuit to the compressor. We are also wanting to install a new EV Charging Station (which is also 240V 30A). Can we ask an electrician to install the EV Charging Station (or to add a 240V NEMA outlet) on the same circuit as the Air Conditioner or do we need to have an entirely new circuit run from the main box for the EV Charging Station?

  • will you ever want to charge and use AC at the same time?
    – Jasen
    May 2 '20 at 0:47
  • Do you have space in your panel for more circuits? Is the air conditioning compressor near where you'd want to plug the EV charger in? May 2 '20 at 0:51

Nope. EVSE's need to be on a dedicated circuit. That's a Code requirement.

The amps of the service don't decide how many spaces are in the panel. "spaces" and "amps" are totally different numbers, you can have 12-space 200A or 42-space 100A. It sounds like you need to add a subpanel somewhere convenient. I recommend counting the spaces (not circuits) you now have, subtract that from 50, and get a subpanel with about that many spaces.


I believe you'll need a new circuit. Fixed appliances generally require dedicated circuits. But from a more practical view, how would you plan on not using both at the same time? If both being used at the same time would almost surely trip the breaker.

  • Thanks for the info. I figured that was going to be the case. I don’t have any more space at the main panel (it’s 200A service). They put a lot of circuits in when they redid the electrical (the house is 112 years old, but the entire house was rewired about 15 years ago). Seems like the best option might be a subpanel and a new circuit). It’s too bad because the AC is right next to where I would want the EV charging station.
    – Justin
    May 2 '20 at 3:05
  • @Justin -- what's the Minimum Circuit Ampacity on the air conditioner nameplate? Also, does your EV charger actually draw 30A? Or does it plug into a 30A receptacle? Finally, do you know what size wire was run for the new air conditioner circuit? May 2 '20 at 6:03
  • in some places it's allowed to fit a switch that affords choosing between two loads.
    – Jasen
    May 2 '20 at 6:11

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