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Need help determining if I can use the charger in my garage

Discussion in 'Charging Standards and Infrastructure' started by ChrisH, Feb 10, 2018.

  1. ChrisH

    ChrisH Member

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    Hello all.

    A couple of years ago, we had a house built and an electric car charger was an add on option so we went for it. I did not know anything about electric car charging back then so I think I may not have the best set up for charging a model 3 when I eventually get one.

    What was installed is a NEMA 6-50. Should be good right? Well, it looks like it has its own circuit, but was installed with only a 40amp breaker and what I think is 8 gauge wiring. Tesla’s guidance seems to be that a 6-50 should have a 50 amp breaker and be installed with 6 gauge wiring. I believe some of the charging systems such as the Watt Station only needed the type of set up that was installed in my garage.

    Can I still use this outlet, but dial down the the amp draw to 32 amps to be safe or am I out of luck because the gauge wiring is incorrect in addition to the breaker?

    Here is a pic of my electrical box. Not a great picture, but the wiring for the 6-50 is the second set of two breakers on the left hand side.I’m guessing that’s only 8 gauge?

    [​IMG]

    We also have a NEMA 14-30 in our garage (because we had washer and dryer outlets roughed in as well) so I might be able to use that, but I’d really like to use the electric car charger we paid for if at all possible.

    Any guidance would be much appreciated!
     
  2. AEdennis

    AEdennis Active Member

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    If you have the new UMC that only draws 32a on the NEMA 14-50 and 6-50
     
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  3. Lloyd

    Lloyd Well-Known Member

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    Use the 6-50 at 32 amps. You will find that it is sufficient.
     
  4. ChrisH

    ChrisH Member

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    Thanks guys...it’s okay to do that even with the smaller wiring and breaker?

    I guess if I get the SR Model 3 it only comes with a 32amp on board charger anyway right so it should all be safe?
     
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  5. fasteddie7

    fasteddie7 Member

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    8 gauge should handle 32a just fine and your 40a breaker falls under the 80% rule when charging at 32a. You should be a-ok
     
  6. BerTX

    BerTX Active Member

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    Just to help out in the future -- the NEMA 6-50 is a receptacle, not a charger. The charger built into the car, your Mobile Connector connects the receptacle to the charger in the car. It is a little confusing to call the receptacle a charger, just like someone might be confused if you pointed to an outlet in the kitchen and called it a toaster.

    You will need to get an adapter for your NEMA 6-50 receptacle from Tesla for $35 to plug in the Mobile Connector.

    Model 3 NEMA Adapters
     
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  7. ChrisH

    ChrisH Member

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    Thanks for the clarification. The builder just called it an electric car charger and installed it in the garage haha.

    Glad to hear the 6-50 should work and thanks for the reminder about needing the adapter!
     
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  8. swaltner

    swaltner Member

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    Also, contact your builder and let them know that if they're going to offer a "car charger" as an option on new house builds, they should do it "right". They might want to install a NEMA 14-50 outlet in the garage (would require an extra wire for neutral, which is why they did a 6-50 outlet instead of the 14-50) but they really should be using 6 gauge wire and a 50 amp circuit breaker. The NEMA 14-50 is the low-cost option that has the most wide spread use on EVs, mostly because it's widely deployed at RV parks. Installing the proper wire and circuit breaker avoid issues when charging cars like the Tesla Model S, which would attempt to draw 40 amps continuous and be unsafe on your setup.

    However, as mentioned, you won't have a problem charging your Model 3.
     
  9. ChrisH

    ChrisH Member

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    Absolutely. When I started looking into Teslas I was upset to learn it was a 6-50 and not a 14-50 and then was more upset to learn it only had a 40 amp breaker. My fault for not doing research prior to paying for something though!
     
  10. TexasEV

    TexasEV Well-Known Member

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    Some 30 or 32A J1772s are made to plug into a 6-50 outlet. Maybe the builder was saying it was EV charger ready (actually EVSE ready) rather than the charger itself?
     
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  11. Rocky_H

    Rocky_H Active Member

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    I disagree with that. There is no reason to use a 14-50 instead of 6-50 for electric car charging. Car charging will only be using the 240V connection, which a 6-50 has, rather than the 120/240V dual voltage options that RV make use of in a 14-50. 6-50 has everything a car charging connector will need, and is one less wire to have to run, since the neutral is going to be unused anyway, so it is sensible and cost effective.
    However, yes, having it with 8 gauge and a 40A breaker is not a very smart choice. There is an exception in electric code that if you know you are going to use it for a 40A rated appliance, you can use a 50A outlet type with a 40A breaker, because there is no 40A outlet type. But that would be for a known 40A appliance. When they are including this in a new house build, they don't know what type of EVSE the new owner is going to use, so the 6-50 or 14-50 on a 40A circuit is kind of inappropriate and dangerous.
    Yes, in this case, you're all set, because the mobile charge cable that comes with the Model 3 has a 32A limit anyway, which is already set for a 40A circuit type. I don't remember if the new cables come with a few more adapter types or not. So if it doesn't come with the 6-50 adapter, you would need to get one of those.
     
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  12. TexLaw

    TexLaw Member

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    It's nice of you to try to give the builder some motive besides cutting improper corners in order to put money in his pocket, but that outlet should have a 50A breaker and proper wiring.
     
  13. Rocky_H

    Rocky_H Active Member

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    Well, let's go with what's common, though. Every electric car on the market except for Tesla has a 6 or 7kW onboard charger at the maximum. So a 40 or 30 amp circuit is the common denominator. That's why almost every public charging station from Chargepoint, Blink, Semacharge, Greenlots, Aerovironment, etc. etc. is 30A. That's what's standard. So what I have heard of more commonly in these kinds of "EV ready" new house constructions is to put in the circuit that's 30 or 40 amp and run it to a location in the garage, but then end it with capped wires and maybe a blank cover plate. So the circuit level is to be expected, but I think it was bad form to put a 6-50 outlet on it, which is misleading if you don't know to double check what's behind it.
     
  14. TexLaw

    TexLaw Member

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    My point, exactly. I'm of the school that, if you are going to install a receptacle, you wire it up to its full capability (unless you just cannot, due to service restrictions, in which case you indicate max amps on the receptacle).
     
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  15. SteveB26

    SteveB26 Member

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    I think that they should have put a 90 amp breaker and wire and put in a wall charger for a Tesla that can pull 72 amps :) BUT I stupidly went through the same thing new construction they installed a 40 amp breaker and cable and just left it in the garage and when I bought my car and wall charger the electrician hooked it up but I only pull 32A which is more then enough for my needs but still would be nice to get 48 of 72 which would require me to upgrade the board in my car to accept 72 amps (Tesla told me my car can take it but it would cost a couple grand).
     
  16. Rocky_H

    Rocky_H Active Member

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    There are two equally valid choices to do it properly; we're just preferring different ones. You're saying to increase the breaker and wire. But since Tesla is the only company that makes a 10kW onboard charger, I think that's overkill for what usually isn't necessary. I would say 40A and 8 gauge is fine, but they should leave the end with just wire nuts instead of putting a wrong rated outlet on it. Because a lot of people with electric cars are just going to remove the outlet anyway to put a 40A hardwired EVSE like a Clipper Creek CS-40, on it anyway, and the open wire ends are already set up for that.
     
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  17. ChrisH

    ChrisH Member

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    Thanks for this. You saying it is inappropriate and dangerous makes me worried but you are more meaning vehicles that can charge higher than 32amps would not be safe with this set up but the model 3 is because of the new umc limit of 32amps right? I know I will have to buy the 6-50 adapter. Thanks again.
     
  18. imjustdave

    imjustdave New Member

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    This to me is the example of you tried to show you tried but really the effort was half @#$ and you want credit for it.

    At the end of the day your builder and or electrician or both basically pulled a fast one "OOO look Pretty plug for you green car" See you new home is all ready for you.... BUY BUY BUY... Then you move in and look at the details. 40 amp breaker, 6 gauge wire pretty basic EV plug that yes qualifies for some cars but at the low end really. Even if you didn't own a EV and want to use a welder, table saw, or big air compressor AKA something in the garage that needed real power I feel 50 amp would a have been a real benefit, yes there are 30 and 40 amp requirements of garage toys, but 50 is a cover all options sort of thing. even big RV could use it without an adapter. And then there is the real story behind all of this... Most garages have the main panel so the plug is close by. The cost difference is basically in the wire maybe a $1 more a foot seeing as it should have the 4th wire with it, Labor, breaker, staples to hold the wire I feel even the outlet might be cheaper as its more common. And none of this would be out of scope of the home anyways assuming it has a oven. So yeah I would view that execution as sub par, I would even call them out on it. it will work and overnight charging should be plenty long to charge a car.

    Sorry for my rant i just dislike stuff like this
     
  19. Rocky_H

    Rocky_H Active Member

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    Yes, that's right. The thing is, it is an exception case in the electric code to be able to put a 50A outlet type on a 40A circuit. That is not normally done most of the time. The valid condition of the exception is if it is known to be installed for a 40A rated appliance. Many (most?) ranges are 40A. So for the stove outlet that gets run from the panel to the kitchen, it is very common to run that as a 40A circuit with a 14-50 on it. You know it's going to be an oven there. No one is going to plug a welder or RV into their kitchen outlet. This case of the pre-built circuits for electric car charging is too open-ended and unknown what is going to be plugged into it, so it is irresponsible for them to put in that 50/40 exception case without any information of what the new homeowner is going to plug into it. They need to have it with the full 50/50 rating if they are going to put an outlet on there.

    But yes, with the Model 3's cable, it can only pull 32A maximum no matter what, so that's already sized correctly for a 40A circuit anyway, so it can't be a problem with that charging cable. The thing that would be bad would be if another Tesla owner came to your house and plugged their original style UMC into it. That would try to pull 40A continuously, maxing out the circuit, heating it up, and (hopefully) tripping the breaker before something worse happens.
    Yes, absolutely half-assing it.
     
  20. miimura

    miimura Active Member

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    #20 miimura, Feb 23, 2018
    Last edited: Feb 23, 2018
    Here is a list of EV charging equipment that can directly plug into the OP's NEMA 6-50 outlet connected to 8ga wire and 40 amp breaker with everything exactly within specs:
    - Tesla Mobile Connector Gen2 w/ 6-50 adapter
    - Clipper Creek HCS-40P
    - ChargePoint Home 32A
    - Leviton EVB32-5ML
    - Siemens Versicharge VC30GRYU
    - Aerovironment EV Charger
    - Bosch Level 2 Plug-in EV Charger

    In fact, JuiceBox and Clipper Creek are the only major makers I can think of that offer plug-in EVSEs with NEMA 14-50 plugs. The only 40A EVSEs that have a 6-50 plug that would draw more than the 40 amp breaker could handle are the Tesla Mobile Connector Gen1, the Leviton EVB40 series, the 40 amp version of the Bosch unit, and the Clipper Creek HCS-50P. 30 and 32 amp EVSEs are far more common than 40 amp EVSEs, so I don't fault the builder for doing it that way.
     
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