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80A Wall Charger wiring

Discussion in 'Model X: Battery & Charging' started by jgalak, Jul 26, 2017.

  1. jgalak

    jgalak Member

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    Location:
    Bellmore, NY
    I was going to just get an outlet, but since a) I want a cord to stay permanently at home to avoid having to get it in and out of the car each time, b) I want a mobile charger to stay in the car for on the road use, and c) a second mobile charger costs about the same as a wall charger, I'm just going to install a wall charger.

    Since I have 200A service and a very short run from panel to charger, I figure I might as well wire it for full-bore 80A charging. The charger will be outdoors. While I'll have an electrician do the work, I like to go over everything myself, first. It looks like #4 THHN wire in 1" PVC conduit should be sufficient for this application.

    What I'm wondering is whether an outdoor disconnect is required. I suspect it is, based on the amperage, but would love to not have one, as the charger itself is a nice clean unit to put on the side of the house, whereas the disconnect is an ugly industrial box.... So, any legal way to avoid the disconnect?
     
  2. jeffro01

    jeffro01 Active Member

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    You're going to need #2 not #4, with a #6 ground... 1" conduit size is fine. Keep in mind to get the full 80A charging you need to be on an 100A circuit. There's a 20% reduction for continuous current applications.

    Regarding the disconnect, that's a question for someone who's more familiar with the code requirements for your area than I am...

    Jeff
     
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  3. animorph

    animorph Member

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    Location:
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    You can read the HPWC manual for the installation requirements. #2 copper and conduit is specified there.

    The disconnect is a local thing, you may or may not need it, depending on your city. You'll have to look it up. You usually need a permit as well.

    You need to do a load calc (you can find calculators online) to see how a new 100A circuit might fit in safely with your other usage. Actually, for the current 72A car chargers, only a 90A circuit is required, but there's probably not much cost savings there. Does your 75D come with the bigger charger or the 48A charger?

    The other benefits of the HPWC are: it can be set work with a variety of circuit breaker sizes, something like 16A to 100A, and you can add multiple HPWC's (newest version) to the same circuit and they will cooperatively share the available current. That gives you flexibility if the load calc says you can't support a full 100A circuit or if you expand your EV car collection.
     
  4. brkaus

    brkaus Active Member

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    Typically 60A does not require the nearby disconnect. If looks are important, this might be an option.
     
  5. jgalak

    jgalak Member

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    Location:
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    No, the MX 75D only has the 48A charger (and no option anymore) but if I'm putting in the wall connector anyway, might as well try to future-proof.
     
  6. brkaus

    brkaus Active Member

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    Agree. I was told I don't not have capacity on a 200A panel. Large house, multiple ovens, HVAC, etc.

    Just throwing it out there as an option.
     
  7. Rossy

    Rossy Supporting Member

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    I have 400A service (320Amp continuous) so 2EA 200Amp panels. Was thinking about putting in a 100A HWDC charger, but decided as we had #6 THHN left over from a hot tub install to just run 1" conduit and a 14-50 69Amp circuit. I figured we can update to 100Amp if we get another Tesla use the same conduit and extend it for the HPWC unit and daisy chain two of them. The cost $500 vs ~$7.00 for the NEMA receptacle wasn't worth a faster charge time in my mind for only one car.
     
  8. Rocky_H

    Rocky_H Active Member

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    There is at least one violation of electric code in what you're describing.
    (1) Quote: "14-50 69Amp circuit" No. A 14-50 outlet can only be on a 50A circuit maximum, not 69A. Maybe that was a typo?
    (2) Quote: "I figured we can update to 100Amp if we get another Tesla use the same conduit and extend it for the HPWC unit and daisy chain two of them." I do hope you mean pulling different thicker wire instead of the 6 gauge, since you can't use 6 gauge for a 100A circuit.
     
  9. Rossy

    Rossy Supporting Member

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    ABSOLUTELY, would have to pull new copper except possibly for GND. Might have to go to 1-1/2" conduit too. But the general idea is that I could bump from 50A to higher current by extending the conduit and pulling new wire.
    Thanks for posting the clarification. Omissions in thought were all my fault.
     
  10. boaterva

    boaterva Supporting Member

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    I'm going to add my standard comment here, which is that you don't 'daisy chain' HPWC's, that's a common misinterpretation of the manual. The data circuit for load balancing is daisy-chained from one to the other (up to four), but the power is essentially 'T'd to each one from a common point. See my sig for pics of my installation of two HPWCs and the excellent FAQ thread of all things Tesla electrical charging by FlasherZ!
     

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