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NEMA 14-50 plug or wall charger?

Discussion in 'Model 3: Battery & Charging' started by eddieb3, Aug 7, 2018.

  1. eprosenx

    eprosenx Active Member

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    Why did he recommend this configuration?

    Also, if your jurisdiction follows 2017 NEC and has not modified it, that 14-50 is required to be on a very expensive GFCI breaker. Did he install one? If the HPWC was hard wired it would. It require one.

    I don’t understand this obsession with plugging in HPWC’s with pigtails. Other than the fact that it violates the install instructions and NEC, it also limits you to 40 amps. I used aboit the only advantage is that it counts as begin a disconnect, although you don’t need a disconnect if your breaker is 60a or below.

    (But from a practical standpoint this is likely not obviously dangerous)
     
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  2. Skione65

    Skione65 Member

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    @SSedan,

    Thank You! ^^^ This. I’m so tired of “The a Tesla Wall Charger on a 100A breaker is overkill” and “You’ll NEVER need that capacity” and “a Nema 14-50 is plenty”! Hogwash.
    I WANT the ability to drive 250 miles home and be able to plug in and charge rapidly if need be and turn right around in an emergency (or not) and drive for dome distance and NOT have to be saddled by a 14-50.
    My Prerogative. I understand if you only have a 20 mile commute. But if we have the wherewithal to install a Wall Charger and want that for ‘piece of mind’ overkill or not....then so be it.

    Kudos to @SSedan for your post!

    Ski
     
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  3. tga

    tga Supporting Member

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    I think you meant "If the HPWC was hard wired it would not require one." Autocorrect, I presume.
     
  4. tga

    tga Supporting Member

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    Well, a 100A circuit is overkill on a Model 3 that can't pull more than 48A...
     
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  5. eprosenx

    eprosenx Active Member

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    Yes! Sorry, was running out the door to drive home from a vacation in my Model 3. :)

    Thanks for the clarification.

    A GFCI breaker is NOT required with a hard wired Wall Connector.
     
  6. SSedan

    SSedan Active Member

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    Valid point but 48amps is still 50% faster than you get from a 14-50 with the Gen 2 UMC.
     
  7. Koflach

    Koflach Member

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    Now, I’m no electrician but my neighbor is. My house has 100 amps (I think that’s how it’s rated) coming in from the street and we have a central AC, dishwasher and dryer in our house and with the potential load of all those running at the same time he did not recommend that I install the HPWC as he felt it would put too much of a strain on my system. Is this a legitimate concern or is he just being overly cautious?
     
  8. eprosenx

    eprosenx Active Member

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    It is important to calculate the loads on your electrical service to determine if you have any capacity remaining to dedicate to an electric vehicle. Most houses have some additional capacity, the question is usually how much. There are NEC sections that go into depth about these calculations.

    With that being said- There are two fundamental ways to connect your Tesla to charge at your house. One is to use a plug in EVSE (Typically the Tesla provided UMC Universal Mobile Charger). The other is to get a hard wired EVSE such at the Tesla Wall Connector. Either one performs the same function.

    Now the question is how much capacity do you have available and which direction do you want to go?

    The UMC can only operate in the increments that they make adapters for it: 12a, 16a, 24a, and 32a (all at 240v - I am ignoring the 120v options) The Wall Connector on the other hand has a lot more increment steps.

    So I actually am a fan of installing a Wall Connector on some higher amperage circuit (say 60a), but then cranking it down via the rotary dial during install to whatever amount will fit within the calculated available load of your main service. It goes as low as a 12a (15a circuit) setting and as high as a 80a (100a circuit) setting. There is no reason you can’t over provision the wire and breaker as long as it is 100a or below. Then the max draw for NEC load calcs is based on the setting. Easy to change later if you get a gas dryer or upgrade your service and now more power can be allowed to the car.

    So to clarify: Nothing is wrong with installing a Wall Connector over just installing an outlet for using your UMC and in fact it might give you more granularity of selection options. But you do need to make sure not to overload that 100a service (or you need to upgrade it) for whatever option you chose.

    Having a UMC on a 30a 240v dryer plugin (24a continuous) is exactly the same as a wall connector on a 30a circuit (or anything above that up to 100a) but set to 24a (30a).
     
    • Informative x 3
  9. rdlink

    rdlink Member

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    Let's not kid ourselves. The Model 3 might be the first Tesla in the house. But it won't be the last and only...
     
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  10. SSedan

    SSedan Active Member

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    So I am going on a longer drive today and the only superchargers en route are a whopping 30minutes from home. So I decided to charge to 100%. Nav has me getting there with 46% remaining.......I might find a120volt outlet for the night or I might not.
    It was darn nice to be able to set percentage to 90% and then just tell it to go to 100 when I got up reducing time spent at 100%.
    Tomorrow when I get home if I do without supercharging it will be nice to put 30miles into the battery just while unpacking in case I need to run an errand. If I do have to stop in Oshkosh to charge so be it but an avoided stop is usually a good thing.
     
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  11. rdlink

    rdlink Member

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    #71 rdlink, Aug 20, 2018
    Last edited: Aug 20, 2018
    Good example of the benefit of having an HPWC. When spending >$60K on a car I don't see why someone would let $600-$2000 stand between them and the best, most seamless charging experience possible.

    I was fortunate in that I was able to install my HPWC myself within 2 feet of my breaker panel. It cost me $40 for wire, and $10 for a 60 amp breaker. But now I have a ton of flexibility, and I will never, ever worry about driving away from my house without my UMC. Beyond that, I have increased the value of my home for the next buyer, if they have a Tesla. And I wired it in such a way that it can easily be converted to a 14-50 if I decide to take my charger with me.

    I understand that some people just don't have the capacity in their current home to get the benefit of a permanently installed charger. Or there may be other challenges, such as being in a condo, etc.. But as @eprosenx said, even if your home doesn't have the capacity to take advantage of the full capability of the HPWC, you can dial it down granularly to match your current capacity, and you have the option to just dial it up if your circumstances change later on.

    My utility plan gives me 12 hours a day (9:00 PM to 9:00 AM) of $.08 KWh juice, and I looking forward to getting ~44 miles per hour of charging.
     
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  12. Glamisduner

    Glamisduner Active Member

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    Being that I have a really high peak usage and off peak usage rates with the same .09 cents window, I will recommend what I am doing.

    But, keep in mind that my power wire run has to go from the back of the electrical panel, to the complete opposite side of our house through a very small and crowded and old attic crawl space so the cost of heavy gauge wire gets expensive very fast.

    Get the 14-50, but have your electrician run 4awg wire.

    If you find yourself needing the HPWC you can change the outlet out for the HPWC that will charge at 48 amps.

    Otherwise a 14-50 is probably more handy and should cover your charging 98% of the time, assuming your not an uber driver or something. But if you find this is not the case, you can buy and install the HPWC, and change the circuit breaker froma 50 to a 60amp breaker and you should be Good to Go.

    If your going to need a faster outlet later (second car etc), just have the electrician do another run...
     
  13. eprosenx

    eprosenx Active Member

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    Do be aware that taking the battery from 90% to 100% takes a lot longer than 80% to 90%. I think mine took an hour and 20 minutes on my 60a breaker HPWC. You can't really make use super fast charging for that last little bit. (see the graph below)

    Screen Shot 2018-08-16 at 1.26.37 PM.png
     
  14. SSedan

    SSedan Active Member

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    I tried the same thing in November and the battery had cooled so much the 10-30 outlet couldn't warm the battery enough to charge it in a timely manner.
     
  15. jrc0yne

    jrc0yne Member

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    I am debating what my best option is for charging given the high probability that I will be moving in 1-2 yrs. You mentioned you wired yours in a way that it can be easily converted if you move. Can you please explain that a little more or what should I make sure the electrician does on install to make it easier to remove if I decide to move? Or so I just go with the 14-50 outlet?

    Thanks!
     
  16. SSedan

    SSedan Active Member

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    To swap to a 14-50 later you need a box to mount the outlet to the outlet and an appropriate breaker all of which is cheap, but an electrician cost money honestly the labor to show up will take longer than the project.
     
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  17. rdlink

    rdlink Member

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    I ran 4/3 awg wire for my HPWC. I hooked up the neutral wire in the breaker, and then put a wire nut and tape over the other end of the neutral wire inside the charger. If/when I pull the charger off the wall I will replace the 60 amp breaker currently in the box with a 50 amp breaker, and purchase a 14-50 outlet to mount where the HPWC is now.

    Honestly, if you're truly going to move in a year or two you may really want to consider just putting in the 14-50. That way you can leave it for the next owner, without going through he double hassle of the wiring. That's a personal consideration, based on your tolerance for doing the follow up work when you move, and your daily charging needs.
     
  18. jrc0yne

    jrc0yne Member

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    Thanks for the info! I called my local electrician and was quoted $550 for install of HPWC and approx $140 to have in uninstalled and replaced with an outlet in the future. I am leaning towards going this route for the convenience of the HPWC.
     
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  19. davewill

    davewill Active Member

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    And you need to have run the neutral wire, which isn't used for a wall connector install. That said, I wouldn't convert unless I knew the new owner wanted the 14-50. You may be doing work that someone will just have undo if they decide to install a hard-wired EVSE. You would also be obscuring the fact that the circuit is capable of more than 50a. Better to just turn off the breaker, cap the wires off, and install a cover plate when you move out.
     
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  20. tga

    tga Supporting Member

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    Or forget the neutral and install a just-as-good 6-50. Many non-tesla EVSE's (sanely) use them.
     

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