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Installing both 14-50 and HPWC in 60 amp subpanel

Discussion in 'Model X: Battery & Charging' started by martinicus, Sep 10, 2016.

  1. martinicus

    martinicus Member

    Aug 15, 2016
    North NJ
    I'm planning my electrical work to my detached garage and my electrician said I only have room to run max 60 amps to a subpanel in the garage, not 100. Ideally I would like the convenience of the HPWC plus a 14-50 outlet for backup and compatibility with other cars, but I wouldn't use the two simultaneously. Would it be against code to have both a 60 amp breaker and a 50 amp breaker in the 60 amp subpanel? Or would I be able to install a transfer switch to choose which one is powered? Of course I can just install the 14-50 and save the money, but I'm curious.
  2. FlatSix911

    FlatSix911 Porsche 918 Hybrid

    Jun 15, 2015
    Silicon Valley
    I installed both a HPWC and a NEMA 14-50 in my garage on a 50A circuit without a problem.
  3. davewill

    davewill Member

    Feb 5, 2014
    San Diego, CA, US
    Here's what I would do. Put in a 14-50 and put a 14-50 plug on the HPWC and plug it in. Then you can unplug it if you need to use some other EVSE. The difference between 40a charging and 48a charging isn't really so much.

    Or if you just HAVE to maximize the HPWC, you could put in a 14-60 and put a 14-60 plug on the HPWC. Then make a 14-60 to 14-50 adapter to use with a UMC or other EVSE. But it the unusual plug and receptacle would be a nuisance to buy.
  4. ccutrer

    ccutrer Active Member

    Sep 3, 2015
    Saratoga Springs, UT
    If you can convince the inspector that it's "highly unlikely" that both the wall connector and the 14-50 would be in use at once, you're fine. A skeptical inspector may require a physical lockout means (transfer switch as you suggested) to prevent simultaneous usage. Or @davewill 's suggestion also accomplishes the same purpose, but some inspectors may take issue with the wall connector not being permanently installed. I also second that 40A vs. 48A isn't a big deal. I use a 14-50, and sometimes the X will knock it down to 30A (I think it's touchy about the voltage fluctuation when the A/C kicks on), and the only time I bother raising it back up is if I've driven 100+ miles in the morning and I may be going out again in the evening.

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