TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

How many amps can the Model S pull from a NEMA 14-50?

Discussion in 'Model S: Battery & Charging' started by William13, Oct 7, 2012.

  1. William13

    William13 Member

    Joined:
    Mar 19, 2011
    Messages:
    943
    Location:
    South Bend
    I have wired for my HPWC but it will not be available when the car is delivered. The electricians placed a NEMA 14-50 plug for now. Ordinarily this plug would be limited to 40 amps continuous. Will the Model S pull only 40 amps or will it pull 50? How dangerous would it be? It is on a 100 amp breaker.

    Later it will be replaced by the HPWC.
     
  2. dhrivnak

    dhrivnak Active Member

    Joined:
    Jan 8, 2011
    Messages:
    2,150
    Location:
    NE Tennessee
    By code and by any licensed electrician, you are limited to 40 amps of charging. Legally an electrician can not put a 100 amp breaker on a plug rated 50 amps. That said I have a 70 amp breaker on my NEMA 14-50 and I have successfully pulled 64 amps for hours with no ill effects, my set us is not designed to be pugged into on a normal basis. But that said I know if "inspected" I would have to replace the 70 amp breaker with a 50 to be fully code compliant.

    I also suspect the Tesla cord to plug into a NEMA 14-50 will be limited to 40 amps just like the Roadster.
     
  3. doug

    doug Administrator / Head Moderator

    Joined:
    Nov 28, 2006
    Messages:
    15,914
    Location:
    Stanford, California
    Probably the most the UMC will allow you to pull is 40A set via the pilot signal.
     
  4. doug

    doug Administrator / Head Moderator

    Joined:
    Nov 28, 2006
    Messages:
    15,914
    Location:
    Stanford, California
    Aren't you allowed to have two outlets on the same breaker?
     
  5. Andrew Wolfe

    Andrew Wolfe Roadster 472 - S 440

    Joined:
    Jun 20, 2011
    Messages:
    573
    Location:
    Los Gatos, CA
    Yes, in some cases - but the breaker cannot exceed the capacity of a single plug.
     
  6. ChadS

    ChadS Petroleum is for sissies

    Joined:
    Jul 16, 2009
    Messages:
    2,401
    Mine's plugged in to a 14-50 now; I just verified that I can't ask it to pull more than 40A.
     
  7. goyogi

    goyogi Member

    Joined:
    May 22, 2011
    Messages:
    415
    Location:
    ::Silicon Valley:: ::Home of Tesla::
    How does it know how many amps it can pull?
     
  8. Lloyd

    Lloyd Active Member

    Joined:
    Jan 12, 2011
    Messages:
    4,886
    Location:
    San Luis Obispo, CA
    That is why the breaker needs to be paired correctly. A fire can result!
     
  9. dadaleus

    dadaleus 4GETOIL P85#S70,FdrX,S85D

    Joined:
    Aug 27, 2009
    Messages:
    884
    Location:
    Solana Beach, California, United States
    I think the Tesla connector tells the car the maximum. On the Roadster (others here will have a better technical explanation), changing the tip on the UMC actually changed the maximum the car will draw accordingly. The Model S one does the same thing with the 120 volt vs. 240 volt tips. I assume this would be true for other tips as well, but I haven't seen them yet.
     
  10. vfx

    vfx Well-Known Member

    Joined:
    Aug 18, 2006
    Messages:
    14,792
    Location:
    CA CA
    How many ping pong balls fit in the frunk?
     
  11. bonnie

    bonnie Oil is for sissies.

    Joined:
    Feb 6, 2011
    Messages:
    14,241
    Location:
    Columbia River Gorge
    What color is the sky over there?
     
  12. ModelS1079

    ModelS1079 Member

    Joined:
    Jun 23, 2012
    Messages:
    837
    Location:
    Suburban Boston
    Pulling more than 40A from a NEMA 14-50 sounds like a bad idea. So, teach me, my friends more geeked than I: I understand a NEMa 14-50 can carry 50A, but that's an over-build so it'll safely carry 40A. So that explains NEMA 14-50. But what do NEMA and 14 mean?

    - - - Updated - - -

    Okay, even a junior-varsity geek can google:

    http://en.wikipedia.org/wiki/NEMA_connector
     
  13. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

    Joined:
    Jan 29, 2010
    Messages:
    6,097
    Location:
    Redwood Shores, CA
    The next Google tech interview question, I'm sure. They had a version of it for a school bus :)

    Apologize on Eric's behalf for going off-topic...
     
  14. Timothy

    Timothy Driving on Sunshine

    Joined:
    May 4, 2011
    Messages:
    287
    Location:
    Santa Barbara, CA
    And for a elementary school geek who can google, I learn our cars are actually electric ranges! :wink:
     
  15. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    NEC 210.21(B)(1): "A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit."
    NEC 210.21(B)(3): "Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3), or, where rated higher than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating."

    The only place where a smaller receptacle rating is allowed versus the branch circuit rating is where 15A receptacles are used on 20A circuits (120V). So, 50A breaker maximum on any circuit that has a NEMA 14-50R attached.
     
  16. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,252
    Location:
    Silicon Valley
    Yes, that is correct. When you change plug ends it has a mechanism to tell the UMC to adjust the ampacity signal accordingly.
    So the UMC then tells the car not to draw more current than is considered safe for the plug type in use.
     
  17. jkirkebo

    jkirkebo Model S P85+ VIN 14420 EU

    Joined:
    Jun 13, 2010
    Messages:
    950
    Location:
    Fredrikstad, Norway
    Correct me if I'm wrong, but I don't think the UMC supports more than 40A anyway ? So 40A would also be max on a 14-60 plug ?
     
  18. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,252
    Location:
    Silicon Valley
    For Roadster, yeah, I think 40A was max...
    http://www.teslamotors.com/roadster/charging/universal-mobile-connector
    So, it puts out 40A signal for NEMA 14-50, NEMA6-50,and lower signals when it detects other plug ends.

    So far, it looks like Model S UMC is also 40A max:
    http://www.teslamotors.com/models/charging/#/outlet
    I don't see any mention of NEMA 14-60 plug support there at all.
     
  19. dmetcalf

    dmetcalf S258

    Joined:
    Jun 2, 2012
    Messages:
    131
    Location:
    Merritt Island, FL
    My 14-50 draws a max of 40A and takes 245 V for 31 mi/ hr of recharge. 28 mi/hr of recharge if I am sitting with air on and listening to music...
     
  20. ModelS1079

    ModelS1079 Member

    Joined:
    Jun 23, 2012
    Messages:
    837
    Location:
    Suburban Boston
    Yes, and I believe there is a self-cleaning option for the Model S as well, like the Electric Range.
     

Share This Page