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Combining two 110v/12A circuits?

Discussion in 'Model S: Battery & Charging' started by hemants, Feb 26, 2015.

  1. hemants

    hemants Member

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    My garage has 4 110V outlets. When I charge currently I get 120V/12A of charging.

    Presumably each outlet is rated for 12A of current. Is there any way I could combine two outlets into one and get 20 amps of charging?

    from the quotes I've received for Nema 14-50, the physical 50 amp wire and fishing through the basement into the garage is the largest expense.

    I've been 'okay' with 12A but would be happier with 20.
     
  2. CmdrThor

    CmdrThor Member

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    Presumably all 4 outlets are on the same circuit. You should contact a licensed electrician. Electricity is dangerous and you could kill yourself.
     
  3. FlasherZ

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

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    #3 FlasherZ, Feb 26, 2015
    Last edited: Feb 26, 2015
    Can you do it? Yes, under certain circumstances. Is it safe? No. See my FAQ in my signature, below, for more details, specifically the question about the "Quick220" type devices, and parallel circuits, which are disallowed by NEC.

    As noted by CmdThor, all the outlets may be on the same circuit so it wouldn't help you anyway. In my attached garage, all of them are, and it wouldn't help anyway because the circuit rating is 20A.

    Your easiest bet would be to take a look at your wiring to see if it is #12. If it is, then you can install a 20-amp outlet (NEMA 5-20) and order the adapter from Tesla which would give you 16A charging. Your best bet is to make the investment to have a NEMA 14-50 installed.

    There are other solutions in between - especially if you have multiple circuits in the garage, but they involve doing things that probably shouldn't be done.
     
  4. wycolo

    wycolo Active Member

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    #4 wycolo, Feb 26, 2015
    Last edited: Feb 26, 2015
    With a voltmeter check between all 4 'hot' sides (the narrower slot in each wall socket). With luck you will discover 240 volts between some of them. The closest ones could provide a convenient 240 volt source to charge your Tesla. Drawing 12 amps max from each leg will make a big difference!

    Approach this in a careful adult fashion etc etc YMMV caveat emptor . . .

    Edit: You are only going to get the 12A you are now getting, but at 240v instead. The MS charges with less energy loss at the higher voltage. But like the others have said, do a rewiring job and charge at 20A or much higher, and enjoy quicker charging.
    --
     
  5. TexasEV

    TexasEV Active Member

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    You would be even happier with 40A charging. It's a whole different experience. For what the cars cost, I just don't understand people wanting to try various gimmicks to avoid the usually minor additional expense of installing a 50A circuit to get the 40A charging the car was designed for. Just consider it part of the cost of the car.
     
  6. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I completely agree with FlasherZ's advice.

    I have a "Quick220" and besides the safety issues, it's just a pain in the a** to use. The biggest problem is that the "Quick220" will not work with 120V circuits that have GFCI protection. All modern garage, kitchen, bathroom, and outdoor outlets have GFCI protection per code. Because the "Quick220" does not return any current to neutral, it immediately trips a 120V GFCI. Although I have tested the "Quick220" to verify operation, pulling extension cords out of the house from non-GFCI outlets, after owning it for 5 years with Teslas, I have never used it for an actual, needed charge. Don't bother!

    The UMC and HPWC include 240V GFCI's for safety. If at all possible, I recommend installing a 14-50 outlet for the UMC or better yet, just put in an HPWC and leave the UMC in the car for when you need it.

    Good Luck!
     
  7. FlasherZ

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

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    (Not to mention you need to have beefy 10-ga extension cords with high-quality thermoplastic plugs - not the cheap ones that melt - on them for the current you're going to haul through them... they'll run you well over $70 each, if not $100. Need two of them? You've just invested nearly $200 that would go toward a 14-50 install.)
     
  8. Rockster

    Rockster Active Member

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    I believe it cost me around $200 to have my 14-50 installed. One phone call and less than an hour of our electrician's time, it was done.

    Absolutely worth it. (Of course, a few months later I upgraded to hundred amp and an HPWC but that's a different story. :rolleyes:)
     
  9. CHG-ON

    CHG-ON Still in love after all these miles

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    I completely agree with FlasherZ. Don't try this as it is a HUGE fire hazard. Spend the $ for an electrician and you will be able sleep soundly. I do a lot of electrical work and have learned to never take the risks for forgranted.
     
  10. wycolo

    wycolo Active Member

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    Someone curious enough to know about 'finding both phases' is naturally going to start poking around. Using the voltmeter before removing any box covers is a good start as it will show if 240v is available or not. Then removing cover plates to inspect the wiring to sketch the circuits. One may discover an unused 10 ga pair intended for some future 240v appliance, but capped off for the time being!
    --
     
  11. uselesslogin

    uselesslogin Enthusiast

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    #11 uselesslogin, Feb 27, 2015
    Last edited: Feb 27, 2015
    My only thought is if it is a 20amp circuit and breaker. If the wiring is sufficient gauge you could replace the outlet so that it has the one prong at the right angle (NEMA 5-20) and then Tesla sells the NEMA 5-20 plug. That will get you from charging at 12 amps to 16 amps. That isn't a big upgrade but only thing that sounds reasonably safe to me besides getting a new circuit.

    And just to explain a 15 amp circuit is rated for 12 amps of continuous draw and a 20 amp is rated for 16. It is always 80% of the breaker for continuous draw.
     
  12. Cosmacelf

    Cosmacelf Active Member

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    First step, just see what breaker your garage plugs are connected to. If it 20a, then you will likely have an option to easily and cheaply convert one of your garage plugs to a NEMA 5-20 outlet (looks the same as a regular 5-15 outlet, except that it has a horizontal notch in the left blade). You could then charge at 16 amps instead of 12 amps, giving you about 43% faster charge.

    ImageUploadedByTapatalk1425224348.718598.jpg
     
  13. wycolo

    wycolo Active Member

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    Assuming the cover plates are removed to check if the wiring gauge can actually justify either the breaker or outlet rating. One never knows . .
    --
     
  14. tga

    tga Active Member

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    Personally, I wouldn't trust that - unless you can inspect the entire run, you can't be sure there isn't some 14 gauge wire somewhere in line.
     
  15. rpo

    rpo Member

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    I use a Quick220 for 100% of my charging at home and have used it four times at different homes while on road trips. It is totally safe to use, but like others said, you cannot use it on GFCI outlets. My older home does not have any, so one end is plugged into the garage and another about 20 feet away in my basement. I used the Quick220 because my house does not have enough power for a 50 amp dedicated circuit.

    I charge at 246 volts with 12 amps. That gets me 8.8 miles per hour which is plenty for my usage. A single 120 outlet at 12 amps in my garage only yielded 3.4 miles per hour. Plus on road trips, where I am staying for a day or more at someone's house, I can always find two outlets on opposite phases to charge. It makes those desolate destinations without a 240v outlet feasible instead of relying on 120v where it can take 3 days to charge!
     
  16. FlasherZ

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

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    It is not totally safe to use. There are plenty of failure scenarios that devices such as that do not take into account. Not only that, but it violates NEC and comes with liability and insurance implications.
     
  17. rpo

    rpo Member

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    What failure scenarios would those be? NEC doesn't cover temporary electrical installations, and since that is what the Quick220 would be, it doesn't apply.
     
  18. FlasherZ

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

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    The NEC does indeed cover temporary electrical installations. Article 590. 590.2(A), "Other Articles", says "Except as specifically modified in this article, all other requirements of this Code for permanent wiring shall apply to temporary wiring installations." That includes most of articles 250 (grounding), 300 (wiring methods), and 625 (electric vehicle charging).

    The Quick220 suffers from several deficiencies. The primary violation is 300.2(B), stating all conductors of the same circuit and equipment grounding conductors shall be contained within the same raceway, cable, or cord, from the panel. However, there are numerous violations of grounding code because of multiple EGC's from separate circuits; lack of common-trip for all ungrounded conductors; among others.

    When two grounding conductors are used, the failure of a neutral in a feeder -- say to a campground pedestal, which is more common than you might think -- can create a situation where return current will flow through the grounds on the Quick220 device, or in some cases, leave exposed parts of the device at 120V to ground.

    It's a bad idea, period. Do it right the first time so people don't get killed.
     
  19. scottm

    scottm Active Member

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    What Tesla adapter tip do you use on the mobile charger to connect to the quick220?
     
  20. wycolo

    wycolo Active Member

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    If someone has a Quick220 try replacing the outlet with a gfi and see if it can work or just trips out 100% of the time. I'm guessing as you start to draw real current (more than a couple amps) the separate return paths will differentiate by >.01 ma and game over.

    House wiring convention is that all conductors must terminate in boxes open to room inspection. If you suspect cobjobbery then kill entire house and bring up breakers one at a time as you draw up a sketch.
    --
     

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