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getting HPWC .. what do I tell the electrician..

Discussion in 'Model S: Battery & Charging' started by rekoh, Jan 21, 2013.

  1. rekoh

    rekoh Member

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    My home was built about a year ago, and I put in a dedicated 220v line (see picture) -- I am not sure what I need, but I would think that this breaker is not enough ... so.. what do I tel lthe electrician I need: Breaker size, outlet, wiresize? breaker.jpg
     
  2. Lloyd

    Lloyd Active Member

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    Show him the installation manual. He can determine the wire size based on what your load will allow.
     
  3. rekoh

    rekoh Member

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    got it.
     
  4. RandyS

    RandyS Fan of Elon

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    Rules are probably different where you live vs. San Diego where I live, but here is the process as I understand it....First off, did you get a single charger in the car or dual chargers? What maximum charging rate are you shooting for if the panel can support it? What is the size of the main breaker in your existing main panel?

    Here's my own thought process...

    1) Before I pull a permit for the install, I need to perform standard load calculations for the panel that include the new charging station. A contractor can do this as well. Here in San Diego, they also allow actual values instead of estimated values, which may also give more headroom in the calculation.

    2) You may want to think of these calculations as arriving at the "Sweet Spot" for the size of breaker you can install without major upgrades. For example, my panel may only support a 40a breaker due to the pre-existing load (without a major upgrade). I probably wouldn't want to do a major upgrade, so 40a may be the size I'm stuck with (or whatever the size is).

    3) Once you have that maximum "Sweet spot" number that you can add, then you or the contractor can pull a permit and start the work. In your case, it looks like you're referring to the 20amp garage circuit pictured? That would work to charge the car, but the rate it would support is only 16 amps (or about 3.3 kW). You could probably install something larger since your house isn't that old. That's what the calcs will tell you....

    4) Once you have the permit, then you or your contractor can start the work. It could involve upgrading the wire and breaker that you already have (Assuming your panel can support it).

    So I think you have a few questions to answer first, and then go down the path to figuring out how big a breaker your panel can support...
     
  5. rekoh

    rekoh Member

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    Yes I upgraded to the twin chargers.
    Yes, the Garage 220v is hte breaker (there are 2 connected - so is that 40amps).
    <--starting to get confused!
     
  6. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    No, that's a 20A breaker.

    Give me a picture of your entire panel and I might be able to tell you more. From what you have posted, I can tell you the wire that is present is insufficient for HPWC or even 14-50, unless your electrician ran heavy wire and put a very small breaker on it (unlikely).

    If your home was built last year, depending upon the size of it, it's going to be either 200A or 400A service.

    There are a number of "load calculation" tools out there that will ask you your square footage, various questions about your appliances, and give you a service size. That will give you an indication of whether you'd need an upgrade or not.

    Let's start with a picture of your main breaker panel and I might be able to help you.
     
  7. Al Gordon

    Al Gordon New Member

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    Simply put....unless you are getting the new charger from Tesla that is to be available probably the end of feb , just have the electrician, which I am, install 2-#6 and a #8 or another #6 for the ground. This will go onto a new separate 2 pole 50 amp breaker in your panel.You do not need a neutral (white cable attached)
    Typically, pending the voltage in your area which can range anywhere from 218 volts to 250 volts between the 2 hot wires, this should give you up to 35 miles per hour of charging.
    The outlets configuration is called a 14-50 125/250 volt outlet or commonly known as a stove outlet.

    even though your put this on a 50 amp breaker it will show as a 40 amp charge and will not allow you to dial it up higher.

    I have an S car and a Roadster and believe very strongly that the 40 amp charge will probably over time be best for the longevity of your batterys.
    The quick charge , i think , is best reserved for people that drive 200 miles per trip and need the quick turn around time.
    Its basically why the Roadster has a storage charge, standard charge, range charge and performance charge.
    Less over a longer period is obviously already being admitted by TM as they have recommended using standard charge most of the time.

    Also if your breaker panel is full, that does not imply that you need a new service. It simply means that you may have to have a separate pony panel or disconnect switch or small 2 pole breaker enclosure fed from the main bus of your existing panel.
    If you do end up getting a high power connector then you might as well run #3 instead of the #6. Either will work with the 50 amp plug but the breaker will change to a 2 pole 90 amp breaker when you get the high power charger.

    hope this helps!
     
  8. alexkiritz

    alexkiritz Member

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    That's pretty insulting to the Tesla engineers who spent a lot of time making sure that that was not the case.

    The speed with which the battery is charged has virtually no affect on battery longevity. Changing from standard charging mode to range charging mode only increases the maximum state of charge that the battery is allowed to attain. It has nothing to do with the rate at which the battery is charged. In fact, the extra charge given to battery in range charging mode is supplied to the battery at slower rate than any other part of the charge.
     
  9. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    #9 FlasherZ, Jan 22, 2013
    Last edited: Jan 22, 2013
    True... however, adding a 80A continuous load does mean you should revise your load calculations, which may require a new service. It sounds as if that 20A "garage" breaker is not in use. It may be a matter of doing a new appropriate wiring run, attaching the HPWC, and swapping the breaker for a 100A version.
     
  10. markb1

    markb1 Active Member

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    By "new charger" I think you must mean the HPWC. If you're not installing a HPWC, Tesla recommends installing a NEMA 14-50R. That will require a neutral connection, even though it's not used by the Model S, due to code. If you want to avoid running a neutral, you'll want to install a NEMA 6-50R. But if you're not installing the HPWC, Tesla only includes one 240V adapter (your choice) and the 14-50 is what you find at RV parks.
     
  11. Lloyd

    Lloyd Active Member

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    Note Title is "Getting HPWC" !
     
  12. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Thanks Lloyd... edited my post accordingly.
     
  13. rekoh

    rekoh Member

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    P1100267.JPG
    Here is my breaker box ... I can upload more photos if you like. THANKS FLASHERZ!
     
  14. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    My rough back-of-napkin calculation says you'll be just fine for an HPWC.

    You have room for new breakers, I wouldn't expect a load problem with that panel. Hand your electrician the HPWC installation guide, it's very short and has the short-n-sweet information she/he will need. If you want something even more brief, just tell her/him that you need a 100A circuit pulled to the left rear of the car.

    If you're not using that 240V, 20A "Garage 220V" circuit, you can re-use the slot there and just abandon the old wiring, but there's no need to since you have room for 3 additional dual-pole breakers.

    I don't expect you'll run into any issues.
     
  15. rekoh

    rekoh Member

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    Awesome.. I will let them know.. the electrician that wired the house was supposed to put in the 220v garage outlet for the sole purpose of charging an electric car. I am explaining that he grossly under-estimated the amperage, and will need to redo that circuit. Plus I will throw him some cash on the side :)
     
  16. rekoh

    rekoh Member

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    spoke with electrician.. they will come out next week and add a new circuit for the HPWC..

    Since that seems to be on back order, here is a question:

    given my panel, and the 240v 20a that I have now, there is no outlet.. just a cover plate. What kind of outlet (receptacle) could/should I put in there --- I will keep that as a backup charger for the hpwc.
     
  17. Zapped

    Zapped Model S - PURE EV

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    Model S cable comes with a NEMA 14-50 plugin adapter
     
  18. EVTECH

    EVTECH Member

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    NEMA 14-50 is the most common. Also used a lot is the NEMA 6-50 adapter. And "rumor has it" HPWC are starting to get shipped out from people's due bill lists.
     
  19. markb1

    markb1 Active Member

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    I don't think Tesla makes any adapters for 20A 240V outlets. And I'm pretty sure it's not legal to install a 30A or 50A outlet on a 20A circuit. What you can do, which is safe and legal, is install a 20A 120V outlet, but that will charge your car very very slowly. (You may have to swap your double pole breaker for a single pole breaker to make this legal. Not sure about that.)

    What I suggest, if you want a good fallback option, is just ask the electrician to install a 50A circuit with a NEMA 14-50 outlet. This will probably require a new run of 6 AWG wire, because the wire run for your 20A circuit is almost certainly too thin. But your electrician should know for sure.
     
  20. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Correct. NEC table 210.24 permits only a 15 or 20A receptacle on a 20A breaker with 12 AWG. And you may never connect a load with a nameplate rating higher than a branch circuit rating. So unless the UMC had a 20A adapter, you can't legally install a UMC with a 10-30/14-30/10-50/14-50 to that circuit.
     

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