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Cooktop/oven and charger outlet sharing same 50A subpanel?

Discussion in 'Model S: Battery & Charging' started by ookma, Apr 5, 2017.

  1. ookma

    ookma New Member

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    Apr 5, 2017
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    Location:
    California
    I have a 120V outlet good for 3 miles/hour charge rate which is sufficient for my daily commute, but having the option to completely charge from empty overnight for consecutive weekend longer distance trips would be nice. I understand a 14-50 requires a 50A breaker and allows charging at up to 40A (about 28 miles per hour), while a 14-30 requires a 30A breaker and allows charging at up to 24A (about 17 miles per hour).

    I have an induction cooktop (240V, 32A max) and oven (240V, 17A max) on an existing sub panel fed from the main panel by a 50A breaker.

    A licensed electrician suggests he could (according to building code) install a 50A breaker on the sub panel running to a 14-50 receptacle for charging. However, using the oven or cooktop during charging would probably trip the 50A breaker at the main panel feeding the sub panel.

    Has any one else had to live with a similar arrangement?

    Would it be better to install the 30A breaker and 14-30 receptacle instead, leaving approximately 26A of "free capacity" for use for the cooktop? The cooktop has 4 burners, rated at 8A, two at 10A, and one at 15A.

    Any other options I've missed?
     
  2. strider

    strider Active Member

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    #2 strider, Apr 5, 2017
    Last edited: Apr 5, 2017
    I would install the 14-50 and just set the car to charge at night. How often are you baking or using the range after midnight?
     
  3. brkaus

    brkaus Active Member

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    I would do the 14-50 and charge at night. You can always set the car at 20a for your typical use.
     
  4. deonb

    deonb Supporting Member

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    Same - would do the 14-50 and just turn the car down to what the lower outlet would have supplied to you.

    That will accomplish the same, but leaves you the option to turn it higher if you need the extra speed and know the oven isn't in use.
     
  5. ookma

    ookma New Member

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    It sounds like the 14-50 it is.

    Unfortunately an inspector I spoke with wasn't sure if it would be up to code when I mentioned "EV charger", since the sub panel (supplied by 50A) should supposedly be sized appropriately for all connected loads with appropriate demand factors. A 40A continuous load alone from an EV charger would be the max allowed (80% of 50A).

    Has anyone else been in this situation? Could I just get a permit for a "general purpose" 14-50 receptacle installation without specifying the purpose (so it wouldn't be considered a 40A continuous load, as a dedicated hard-wired EV charger would)?
     
  6. FlatSix911

    FlatSix911 918 Hybrid

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    Here is what I did ... Installed a transfer switch to isolate the electrical load from the house to EV :cool:

    IMG_3839.JPG
     
  7. tga

    tga Supporting Member

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    Let the electrician handle it. It's up to your electrician to figure out how to install the outlet in a manner that passes inspection, anyway. That's why you're paying them, so you don't get your hands dirty. Let the electrician deal with the inspector.

    As for what's plugged in, it's not really the inspector's business, as long as the circuit is installed correctly and sized for 50A.
     
    • Like x 1
  8. iffatall

    iffatall Member

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    I am using this exact same setup - induction cook top sharing a breaker with 14-50 for charging. I just never charge and cook at the same time and have limited the current to 24A in the car. Have been using it for over three years already.
     

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