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 and becoming a Supporting Member. For more info: Support TMC

Can L6-20 charge at 32A?

Discussion in 'Model 3: Battery & Charging' started by marmot1, May 20, 2018.

  1. marmot1

    marmot1 Member

    Joined:
    May 18, 2018
    Messages:
    6
    Location:
    San Francisco
    Hey folks, new to EVs in general and this gorgeous Model 3 specifically. Thanks for the help here.

    My garage has an L6-20 outlet that I'd like to use for charging (since my only other options are 5-15 normal US wall plugs).

    I bought this adapter on AMZN to convert to a plug that I knew my kit has.

    So when I plug into this adapter and my L6-20 outlet, the car shows 32A and ramps up to that. At this point, I'd expect the breaker to trip...since it's a 20A circuit as far as I understand, but it didn't. The breaker is a double 20A since it's 220V, but that doesn't allow it to flow 2x16A does it?

    In any case, for now I dialed the car back to charge at 16A so I don't burn down the garage overnight, but I'd appreciate advice from someone who really knows this stuff well please! MVIMG_20180520_214050.jpg MVIMG_20180517_095026.jpg
     
  2. yuhong

    yuhong Member

    Joined:
    Mar 11, 2018
    Messages:
    179
    Location:
    Burnaby, BC
    Consider getting the 6-20 adapter for the UMC and either replacing the outlet or use an adapter. And yes it should be limited to 16A.
     
    • Helpful x 1
  3. FlatSix911

    FlatSix911 Porsche 918 Hybrid

    Joined:
    Jun 15, 2015
    Messages:
    5,549
    Location:
    Silicon Valley
    #3 FlatSix911, May 21, 2018
    Last edited: May 21, 2018
    The adapter you purchased is a NEMA L6-20P to 14-50R... so the car thinks you are charging from a 32A continuous load circuit. :eek:
    You should be sure to reduce the charge to 16A in the car and consider using 6-20R adapter rated for a 16A continuous load circuit.

    Model S/X/3 Gen 2 NEMA Adapters
    PDU Whips - Custom PDU Whips and Power Cords for Data Centers
    https://www.amazon.com/NEMA-L6-20P-6-20R-Plug-Adapter/dp/B00DNDYIN6


    [​IMG]
     
    • Helpful x 1
  4. swaltner

    swaltner Active Member

    Joined:
    Oct 13, 2012
    Messages:
    1,179
    Location:
    Kansas, USA
    THIS! Hopefully, you would just trip a circuit breaker, but it could be much worse to use your setup at 32 amps, which is twice what is safe to do.

    I personally despise all the adapters that provide a socket that is rated for higher current than the plug. If you know how to use them, they can be used safely. If you’re not paying attention, they can be very unsafe to use.

    Buying something like a L6-20 to 6-20 adapter, then plugging in the Tesla 6-20 adapter, would force you to the correct current rating for the outlet and wiring. Anyone could safely charge without being concerned about drawing too much current on the wiring and outlet. The two parts you need are:

    https://www.amazon.com/dp/B07736C71R

    6-20 adapter from Model S/X/3 Gen 2 NEMA Adapters

    The confusion you had is why I don’t like the adapters like the one you purchased. These potentially unsafe adapters are not required when you use a proper adapter that doesn’t appear to provide more current than is safe to draw. Part of the problem was the Gen 1 mobile connector didn’t have a 6-20 adapter available, so people came up with these types of adapters that required you to manually turn down the current to safely charge the vehicle. These are not required any more, so I think we should stop using them.
     
    • Like x 2
    • Helpful x 1
  5. TonyWilliams

    TonyWilliams Active Member

    Joined:
    Jun 11, 2012
    Messages:
    1,438
    Location:
    San Diego - Tesla powered Rav4 EV
    I sent the Amazon seller the following question:

    “Why are you selling such a dangerous device, that will allow a Tesla car to use 40 amps (NEMA 14-50) on a 20 amp rated plug?”

    Please, get a proper 16/ 20 amp plug from Tesla. Tesla does not have any “L” series locking plugs, however you can buy a custom L6-20P to 6-20R adaptor from our company for $89 (Quick Charge Power). I’m sure there are others sources, as well.

    Again, at a minimum, you will need to buy the correct NEMA 6-20 plug for your Mobile Connector (UMC).

    Another option, in lieu of the adaptor, is to replace the wall receptacle with a NEMA 6-20R. That probably is probably only $10 at Home Depot.
     
    • Like x 3
  6. TexasEV

    TexasEV Well-Known Member

    Joined:
    Jun 5, 2013
    Messages:
    7,462
    Location:
    Austin, TX
    This was an example of someone not knowing what it is they didn’t know, and could have resulted in disaster. New owners, please do not use any third party adapters unless you’re certain you know what you are doing. And then post your plan here to get a second and third opinion to make sure it’s ok. Stay safe out there.
     
  7. marmot1

    marmot1 Member

    Joined:
    May 18, 2018
    Messages:
    6
    Location:
    San Francisco
    Actually clearly I did have a notion that this was a 20-amp circuit and understand the 80% rule, since I set it to 16A...but I agree with your sentiment of approaching high amperage and adapters carefully.

    Thank you for the responses; this confirmed what I was guessing, but a few inconsistencies remain....why didn't it go to 40A since it's a 14-50R...I would have expected that vs 32A (a multiple of 16 which made me wonder about the L6-20).

    And why didn't the 32A rate trip my breaker???? Perhaps it hadn't actually ramped up above 20A yet to flip the breaker? (does anyone know if these ramp up more slowly than they actually report for safety reasons?). Otherwise I'll be checking that breaker more carefully.

    Sadly I don't own this garage (rental) so I can't modify the plugs, but I really appreciate @swaltner for the suggestion of adapting adapters which will at least tell the charging unit what it's limits are. I'll consider going that route vs having to set the amperage limit and possibly having problems down the road.
     
  8. yuhong

    yuhong Member

    Joined:
    Mar 11, 2018
    Messages:
    179
    Location:
    Burnaby, BC
    The new Gen 2 UMC limits all charging to 32A or less.
     
    • Informative x 1
    • Like x 1
  9. TexasEV

    TexasEV Well-Known Member

    Joined:
    Jun 5, 2013
    Messages:
    7,462
    Location:
    Austin, TX
    The 14-50 adapter for the Gen 2 UMC only draws 32A. The14-50 adapter for Gen 1 UMC draws 40 A.
     
    • Informative x 1
  10. marmot1

    marmot1 Member

    Joined:
    May 18, 2018
    Messages:
    6
    Location:
    San Francisco
    Thank you! That explains it then.

    Along the suggestions of getting adapters, what would you suggest for a safely-adapted L6-30 vs the 20? I think the garage may also have this option. I assume you could just do a L6-30 <> 14-30 adapter, but the Tesla 14-30 adapter and proceed safely?
     
  11. Bad Horse

    Bad Horse Member

    Joined:
    Aug 10, 2017
    Messages:
    127
    Location:
    Overland Park
    I am genuinely shocked that breaker didn't trip. That should give you more alarm bells than the fact the false adapter didn't tell the UMC to reduce itself to 16A draw.
     
    • Helpful x 1
  12. Bad Horse

    Bad Horse Member

    Joined:
    Aug 10, 2017
    Messages:
    127
    Location:
    Overland Park
    See my reply, yeah, that should bother you more than a bad adapter.
     
    • Disagree x 1
  13. marmot1

    marmot1 Member

    Joined:
    May 18, 2018
    Messages:
    6
    Location:
    San Francisco
    Oh absolutely! I was watching it ramp up slowly in amperage and expecting the familiar breaker sound from the panel on the other side of the garage, and it continued on up to 32A before I hit the "stop charging" button and scratched my head and smelled for a burning outlet. It's definitely something I'll mention to the landlord's handyman next time I see him with a big WTF in there.
     
  14. yuhong

    yuhong Member

    Joined:
    Mar 11, 2018
    Messages:
    179
    Location:
    Burnaby, BC
    I wonder which breakers do you have?
     
  15. Bad Horse

    Bad Horse Member

    Joined:
    Aug 10, 2017
    Messages:
    127
    Location:
    Overland Park
    For sure, you might want to in the mean time "exercise" your breakers (turn them on and off and test them) as sometimes being held closed for so long can make them be "stuck", but what it's more of a sign of is a bad breaker. Also, you probably aren't going to smell burning right away, while it's more current than it's rated for, it can "still do it" for a period of time, a few seconds or so isn't really enough time for enough heat to get built up if it's just overloaded by several amps. Obv not ideal for any sort of significant period of time.

    This/how old those breakers are.
     
  16. RandyS

    RandyS Fan of Elon

    Joined:
    Jul 8, 2012
    Messages:
    555
    Location:
    San Diego
    Hopefully not a Zinsco... :)
     
    • Like x 1
  17. marmot1

    marmot1 Member

    Joined:
    May 18, 2018
    Messages:
    6
    Location:
    San Francisco
    I gave them a toggle before this incident, but maybe a few more flips back/forth wouldn't hurt. :)

    As to the brand, see the OP for an image....GE. The likelihood of both of them being bad seems very very low, but who knows.
     
  18. davewill

    davewill Member

    Joined:
    Feb 5, 2014
    Messages:
    966
    Location:
    San Diego, CA, US
    Most circuit breakers trip because they heat up inside. Since you killed the charge really quickly, then either the current had not actually ramped up that far yet, the breaker didn't have time to trip before you stopped, you have a bad breaker or even the wrong breaker. Have it checked out thoroughly.
     
    • Helpful x 1
  19. zosoisnotaword

    Joined:
    Aug 28, 2017
    Messages:
    60
    Location:
    Alabama
    Most breakers are designed to trip instantaneously only at fault level currents, otherwise you would have a lot of nuisance trips every time you start your vacuum cleaner with the coffee maker on. It sounds like you reacted quickly to the ramp, so I doubt it reached its designed trip time for that amount of current, and I definitely wouldn't expect it to trip as soon as it went above 20A.

    See if you can find the model number and pull the time current curve for your breaker off the internet, then you can determine the amount of time it should take for your breaker to trip at 32A. I would expect somewhere around 30 seconds to a minute since 32A is less than twice the frame rating of the breaker.

    Made-up trip characteristic example:
    Breaker XYZ-30 will trip between 15-20 seconds at twice the frame rated current, but at three times the rated current, it will trip in 4-6 seconds. It will trip instantaneously above ten times the rated current.
     
    • Helpful x 1
  20. timk225

    timk225 Active Member

    Joined:
    Mar 24, 2016
    Messages:
    1,550
    Location:
    Pittsburgh
    How long was it drawing 32 amps for without tripping the breakers? I'd be worried about that.

    You have 240 volts, not 220.

    Zinsco and Federal Pacific breakers are crap and known for not tripping, those are GE breakers in your photo. My house has Cutler Hammer CH breakers (with the tan colored reset handle) and they are reputed to be very good.

    I'd be calling your landlord and an electrician to check that breaker panel out. Post more photos and details about it.

    I have my Model 3 charging from my 14-50 oven outlet on a 50 amp CH breaker. A Camco 15 foot 14-50 extension cord reaches it out the door to the car.
     
    • Disagree x 1

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC