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Charging circuit doubling for generator tie-in?

Discussion in 'North America' started by grichard, Aug 9, 2016.

  1. grichard

    grichard Member De-Luxe

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    Location:
    St. Louis, MO
    I just moved, and I'm dealing with getting a charging circuit in my new garage.

    In my old house, I had a circuit installed for powering my main panel with a gasoline generator. (Properly done, with an interlock on the main panel to avoid electrocuting linemen, and an external breaker.)

    In my new house, the 14/50 outlet for the car is in a location that would be convenient for using a generator in an emergency. Anybody know if there is a safe, compliant way to use the same circuit for both purposes?

    I imagine you could achieve it physically by making a Very Dangerous cable that had a live male 14/50 connector coming out of the generator, but I'm looking for a correct solution, not an iffy kludge.
     
  2. ABCCBA

    ABCCBA Member

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    @grichard You have two items to attack separately.

    1. You will need to provide an air gap break point between your main panel feed and the electric meter. So, you will need to install some type of manual or automated isolation device to prevent back feeding to the utility.

    2. To overcome having a 'deadman' type jumper cable with exposed terminals, make a plug-in RV outlet for your 14-50. So, when you are using the 14-50 for charging your car, the UMC plugs into it. However, when you need to use the generator, you plug your homemade RV outlet into the 14-50 and then use a standard generator cable to plug into the RV outlet.

    FWIW - I did a similar thing, making a alternate outlet, for our 14-50. I needed to get from 14-50 to 6-20, but wanted to leave the 14-50 for other uses.

    Another alternative would be to pull your 14-50 outlet and install a junction box with junction blocks inside. Then, install a 14-50 and a RV outlet in parallel.

    2016-04-04 15.45.20.jpg
     
  3. grichard

    grichard Member De-Luxe

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    #3 grichard, Aug 9, 2016
    Last edited: Aug 9, 2016
    Yeah, thinking about it, I think the first problem that you mention is pretty much un-solvable. How could my main panel distinguish whether I'm using a circuit to charge the car or back-power the panel?

    Probably less hassle in the end just to run a separate line for the generator...
     
  4. Craig-Tx

    Craig-Tx Member

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    YIKES! You have a 6-20 protected by a 50 amp breaker? To casual "around the house" hobby electricians reading this, I'd highly recommend not doing this. Chances are the appliance (in this case RV) being plugged into the 6-20 would not be able to handle a 50 amp current in the event of a short circuit, or unusual load. Without proper precautions, this could be a significant fire risk.
     

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