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Home Charging Help

Discussion in 'North America' started by HailMaryPass, Jun 19, 2016.

  1. HailMaryPass

    HailMaryPass New Member

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    Hello,

    I'm in the process of rebuilding my garage, and I need your advice. For some background, I have a Prius Plug-In that I've simply charged using a standard wall outlet. I will be purchasing a Model S in the next few months. I plan to use a HPWC for the Model S.

    What should I tell my electrician regarding HPWC requirements? Also, what are the charging options for the Prius so that I can get a faster charge?

    Thank you.
     
  2. pdxrajiv

    pdxrajiv Member

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    If you use a Tesla trained/recommended electrician, you would have to worry less about the details.
    Find an electrician
    Installing the HPWC on a 50A, 240V circuit is standard - unless you are getting dual chargers and plan to charge at 80A at home. Then, you would want a 100A,240V circuit.
     
  3. ljwobker

    ljwobker Geek.

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    A circuit rated for 50A/240V is almost certainly enough for almost any rebuild - there's not a lot of functional value in charging at 80A instead of 40A at home, at least in my opinion. One thought though if you're rebuilding the garage is to wire multiple locations in the garage for high power circuits - could be both "sides" of a regular two-car garage, or something more exotic depending on the garage layout. But in any case, having it wired to charge two EVs might well be worth the small extra investment if you're already doing substantial work.
     
  4. TexasEV

    TexasEV Active Member

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  5. CHG-ON

    CHG-ON Still in love after all these miles

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    Don't be fooled by the "Tesla recommended electrician" stuff. All I have heard is that they charge a premium for that moniker. Any licensed person can do it. It is exactly like running an electric dryer outlet.
     
  6. TexasEV

    TexasEV Active Member

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    No it's not! A dryer outlet is a 30A circuit. The 14-50 outlet for Tesla is a 50A circuit, and HPWC is typically anywhere from 50-100A circuit. Any electrician can do it, but they should read the cut sheets referenced above, and the HPWC manual if installing HPWC.

    I've heard too many stories of electricians installing 30A or 40A circuits as if it were for a dryer or range. No other EVs can draw such high current, so it's understandable if they're not familiar with the requirements. They need to read the Tesla instructions carefully if they haven't installed for a Tesla before, so you don't end up with less than a 50A circuit.
     
  7. miimura

    miimura Active Member

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    When I had my house built in 2011-2012 the Model S was just being introduced and I did not own any EVs. I already knew at that time that Tesla would use 40A charging. I specified 240V 50A sockets on each side wall of the garage. Without any prompting, the electrician installed 14-50 sockets. It worked out great for my two EVs and I expect that it will be sufficient for a very long time.
     
  8. bmanke

    bmanke Member

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    Relax a bit - he said LIKE installing dryer outlet. Which it is - just with heavier wire and breaker.
     
  9. TexasEV

    TexasEV Active Member

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    He said "exactly like". It's a different breaker, different wire, and different outlet. But other than that, yeah, it's exactly like a dryer outlet.
     
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  10. Rocky_H

    Rocky_H Member

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    Heh, you tell ‘em, @TexasEV . It is similar to, but not “exactly like” putting in a dryer outlet, but yes, any electrician can do it, if they know what is required. Definitely provide the HPWC install guide. If you are getting estimates, just make sure you specify the breaker for the circuit level you want and that it will be a permanent load, supplying 80% current level.

    So, with that being said, I think some people are overlooking something a little.
    @HailMaryPass
    People default to saying 50A circuit, because 40A was what the older Model S onboard chargers would use, and it was a big deal to upgrade to the dual chargers at 80A, but I think that advice is a little outdated with the new Model S refresh. It’s true that the mobile charge cable can only handle the 40A current, but since you said you are going to get a HPWC, don’t get a 50A circuit; get a 60A. There won’t be much cost difference. The newer version of the Model S now has a 48A onboard charger by default as the small one, which would be the level from a 60A circuit.
     
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  11. airbish

    airbish Renegade of Frunk

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    #11 airbish, Jun 20, 2016
    Last edited: Jun 20, 2016
    Some advice on HPWC please.. :) If this is the right thread for it...

    I got my initial quote today. I don't have load/panel space for a full 100Amp drop, but can support up to 60/70. But I am still leaning toward HPWC for a couple different reasons.

    My (tesla-approved) electrician said that the only difference between a 50Amp run or a 60Amp run (to an HPWC) is the breaker. So I believe we are headed to a 60AMP HPWC (delivering 48Amps vs 40Amps on the standard 50A/14-15). I don't have the upgraded (high amp) charger, but I believe it will take the full 48Amps (hopefully delivering ~34Mph vs ~29Mph...assuming I have all that right and am not making a bad assumption.) Maybe not a big deal difference...but I don't see any drawbacks to that (unless I was really pushing the load on the panel.)

    Any issues there?

    Placement.

    My quote includes running the circuit from the basement across the back floor of the garage (under cabinets) to between the 2nd and 3rd bay, then up the wall, into the ceiling and across to the front of the garage (between the 2nd and 3rd bay doors). MS will go in third bay and be very convenient. Only concern there is cable management (unless I just do the 8 foot). Space between the garage door runners is ~14".

    Other option: Put the HPWC on the garage back wall between the 2nd and 3rd bays (with the 25'). This wouldn't be quite as convenient, but it would eliminate a lot of cable run and conduit (and holes in the ceiling). Not quite as convenient, but would also allow for more easy charging of a 2nd EV (at some point in the future) in the 2nd bay. And I almost feel better with keeping that space between the garage doors open (and not having the cable in the way if I want to walk across the front of the garage (doors closed) and get something out of the car/trunk).

    I haven't lived with any of this yet, so would love to hear opinions on these two placement options.

    Thanks!

    AB
     
  12. pdxrajiv

    pdxrajiv Member

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    I know that many members here have the knowledge and interest to understand the tech details.

    FWIW, the quotes I got from the recommended and the non-recommended electricians were essentially the same.
    The recommended electrician knew about Tesla-specific choices and constraints,
    So if one wants to not be bothered with such details, that is a safer choice IMO.
     
  13. CHG-ON

    CHG-ON Still in love after all these miles

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    You are absolutely correct. But the wiring is essentially exactly the same. Any decent electrician shpuld understand the difference between a 30 and 50 amp circuit and the breakers required.

    And for the readers, you can only use 80% of that rating, ie: 40 amps on that 50.
     
  14. dgpcolorado

    dgpcolorado Member

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    There is a slight difference between 50 A and 60 A circuits besides just the breaker: the former can be 8 AWG wire and the latter requires 6 AWG wire, according to my electrician. I had him put in 6 AWG wire for my 50 Amp circuit because I'd rather go with bigger wire. Also, the gauge of the wire required depends on the distance of the run.
    If you don't mind backing into your garage I'd make the circuit shorter and put the HPWC on the back wall. The rear camera and parking sensors make backing in really easy, in my experience. One more thing to consider is running the HPWC cable along the ceiling to keep it off the floor and out of the way (and out of the dirt/mud that accumulates on the garage floor in my case since I live on a dirt road in snow country). Reduces tripping hazards. Just something else to think about when deciding on placement.

    [​IMG]

    While I am using a UMC, an HPWC would be much the same.
     
  15. airbish

    airbish Renegade of Frunk

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    Thanks, yeah I forgot to mention that we had already decided to run 6 AWG regardless.

    I am leaning toward putting it on the back wall. Hopefully there will be some decent savings on the install costs.
     
  16. Rocky_H

    Rocky_H Member

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    If you read Tesla's official install guide they provide for the install of the 14-50 outlet:
    https://www.teslamotors.com/sites/default/files/downloads/US/universalmobileconnector_nema_14-50.pdf

    They actually do say this:
    "Conductors: 6 AWG, Copper Wire Only. Upsize wiring for installations over 150 feet"

    So maybe NEC tables say 8 gauge is OK for a 14-50, but Tesla has always said to use 6 gauge for this. Possibly that is because of it being a heavy long term load.
     
  17. dgpcolorado

    dgpcolorado Member

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    #17 dgpcolorado, Jun 21, 2016
    Last edited: Jun 21, 2016
    Makes sense. I've always gone one gauge bigger on my EVSE installations, in part for the heavy, continuous load safety, and in part for reduced losses to resistance. Although they are much the same thing in the end. I noticed when I purchased my 14-50 receptacle that it was designed to accommodate very big wires.

    I run my UMC at 32 amps to reduce heating and stress on it; despite that, my cord gets fairly warm when charging. I feel a lot better having 6 AWG wire in metal conduits for the circuit supplying it.
     
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