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NEMA TT-30P to 14-50R

Discussion in 'Model X: Battery & Charging' started by dogsx, Jun 12, 2017.

  1. dogsx

    dogsx Member

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    We just took delivery of our X in May. We charge with a 50 amp at home but wanted a back up way to charge when visiting friends. They have 30 amp RV outlets. We ordered the NEMA TT-30P adapter. It is for EV not the RV type. We also have 30 amp RV outlets so were able to test the adapter. It won't work. The company sent a second one thinking perhaps the first one was defective. The second one won't work either. The Tesla charger cord stays red and if you do plug it in (changing the charging volt to 24) it gives an alarm alert. The company doesn't know why it won't work on our new X when apparently they have worked fine on prior year S's. Does anyone know what the problem might be? Thank you.
     
  2. davewill

    davewill Member

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    #2 davewill, Jun 12, 2017
    Last edited: Jun 12, 2017
    Could be a problem with the outlet. Perhaps a bad ground or reversed Hot and Neutral. An RV might work just fine, but the UMC would detect that and fail. I'd try an off-the-shelf TT-30 to 5-15 adapter and plug an outlet tester into it to check that out. You could then try the 5-15 adapter for the UMC and see if that works.
     
  3. CmdrThor

    CmdrThor Active Member

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    I made my own. Get one of these Amazon.com: Camco 55283 30 AMP Mini Replacement Male Plug with PowerGrip Handle: Automotive and one of these Amazon.com: Leviton 55054 30 Amp, 125/250 Volt, NEMA 14-30R, 3P, 4W, Surface Mounting Receptacle, Straight Blade, Industrial Grade, Grounding, , Side Wired, Steel Strap, Black: Home Improvement and wire the straight blades on the plug to those on the receptacle and don't wire anything to the neutral on the receptacle. You'll need at least 10/2 NM-B. You'll also need the 14-30 Tesla Mobile Connector adapter.
     
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  4. dogsx

    dogsx Member

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    Thank you davewill. I will have to get a to 5-15 adapter to try this.
     
  5. dogsx

    dogsx Member

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    Oh boy. This made my head explode. :) Thank you CmdrThor.
     
  6. CmdrThor

    CmdrThor Active Member

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    Using a 5-15 adapter you will end up charging at 12 amps which defeats the purpose of the 30 amp plug.
     
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  7. dogsx

    dogsx Member

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    I think he meant to try that just to make sure it wasn't the outlet.
     
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  8. Rocky_H

    Rocky_H Active Member

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    I notice you don't mention where you got this or what "the company" is. I ordered mine from EVSEAdapters.com. You say it's for EV, not the RV type, so I do think you know that if you order this type of thing from a camping type supply store, they are wired wrong for the Tesla charging cables and will not work.
     
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  9. volkerbradley

    volkerbradley Member

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  10. Rocky_H

    Rocky_H Active Member

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    Yes, that's what I got too, because I looked at that big yellow thing and thought that looked like a terrible amount of torque having the weight sticking straight out of the outlet so far like that. And TT-30 prongs are pretty small to hold that much weight at that angle.
     
  11. tga

    tga Supporting Member

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    This is the right answer, primarily because you're using the 14-30 UMC adapter, which will auto-set the charge current to 24A, rather than relying on you to manually lower it from 40A and trust the car to remember it.

    Rather than use 10/2 NM (which is solid and not very flexible), use rubber jacketed stranded 10/3 SOOJ cord (available at Home Depot or Lowes). Yes, /3 - SOOJ counts the ground, NM does not.

    If the OP is handy with a screwdriver, the right thing to do is cut off the 14-50 and replace it with a 14-30. You need to get the polarity correct (on a 120V hot/neutral circuit, the UMC needs to see hot on a particular blade) - see @Cosmacelf 's super awesome homemade adapter doc - http://cosmacelf.net/Home Made Adapters.pdf

    But first verify that hot/neutral aren't reversed as @davewill suggested above. A red light on the UMC when plugging into 120V usually indicates hot/neutral are reversed. You really should fix that; it's a potential shock hazard.

    NEMA connector - Wikipedia
     
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  12. Solarman004

    Solarman004 Member

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    The adapters for RVs are not wired such that they will work on a Tesla. Like others above, I made my own.
    1. When facing the male TT-30 with the round ground pin at the top, the LEFT lower flat pin is Neutral and the Right lower flat pin is Hot.
    2. When facing the 14-50 receptacle with the round ground opening at top, the Left hole gets wired to Neutral, the Right hole to Hot, and the lower hole has no connection (you are using the 14-50 for 120 V, not 240 V).
    3. The Amazon sources listed in the post above are what I used to purchase the plug and socket. I had spare #8 wire at the house which I used to connect the two.This was slight overkill...you can use #10 or larger. Anything smaller than #10 is not rated for 30 amps.
    4. Set the car charge rate to a maximum of 24 amps when using (30 x 0.8). Because the car will recognize the NEMA 14-50 and try to charge at 40 amps default, I also put a label on my dogbone adapter to remind me to dial down the charge rate.
    5. The charging rate is slow as a TT-30 socket is only 120 V, but some of the state parks we go to only have TT-30 and no NEMA 14-50 so it is a valuable adapter to have if you camp.
     
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  13. Rocky_H

    Rocky_H Active Member

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    This is also one of the cases of why some people cut the unused angled neutral pin off of their Tesla 14-30 adapter. You can use the pre-made TT-30 adapter from EVSEAdapters, but plug the Tesla 14-30 plug into the 14-50 outlet, so the Tesla adapter will set the current properly.
     
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  14. Rossy

    Rossy Supporting Member

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    I thought about the risk and decided this was a sound recommendation. What if my wife/kids are in a situation where they need to hook up. Forgetting to set the limit to 24A should trip a breaker...but I'm not sure all RV parks breakers will trip when they should. Ordered the 14-30R receptacle from Amazon. and will order the Tesla UMC adaptor too $45 is cheap compared to bad things that might happen. Not happy with the 14-30R +30-TT solution for oitdoor/wet locations, thinking there should be a better way. But expect I can use 50A, or 15A if it's pouring raining out. Don't want to imagine 120V/30Amp 30-TT to 10-30R in a non GFCI situation meeting a puddle of water at an RV park.
    Assuming I take delivery and go camping. Could have photos next week.
     
  15. Freedom101

    Freedom101 Member

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    Thanks for the info, I just ordered this for my in laws (2 foot chord). Can you confirm whether I need to still change the amperage to 24 while using this one or will the car figure it out? Just trying to figure out if I need to label it for myself (and my wife).
     
  16. Cosmacelf

    Cosmacelf Active Member

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    Since it adapts to a 14-50 plug, you'll have to set the charge to 24 A manually. Yes, good idea to stick a label on the adapter stating that.
     
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