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Best 14-50 Extension

Discussion in 'Model S: Battery & Charging' started by steilkurve, Jul 21, 2015.

  1. steilkurve

    steilkurve Member

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    Which one would folks recommend? Looking for not too bulky. Just want as a backup for when I need to reach far behind a stove to charge. ;-)
     
  2. Zarwin

    Zarwin Member

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    There are multiple RV 14-50 extensions on the market. I bought this one:

    Amazon.com: Camco 55195 50 AMP 30 Extension Cord with PowerGrip Handle: Automotive

    It's very well made, but heavy and bulky, as they will all be. What I find interesting is that the reviews for RV 14-50 extensions like this one have lots of Tesla references. It's a market that companies making these products never expected to be in, but suddenly they are. Don't often see that.
     
  3. steilkurve

    steilkurve Member

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    Thanks. Saw that one. Seems bulky. Anything lighter anyone else?
     
  4. Brass Guy

    Brass Guy Member

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    The cable needs to be rated for 50A. The only way to make it lighter or less bulky is to choose a shorter one.
     
  5. TexasEV

    TexasEV Active Member

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    And if it's shorter it's unlikely to reach from the car in the garage to behind the stove in the kitchen. Are you sure you need to do this? Is there a family member you're planning to visit where you need to charge this way, or are you just trying to be prepared? If it's a relative you visit often, you may want to consider having a 14-50 outlet installed in their garage.
     
  6. pgiralt

    pgiralt Active Member

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    +1 for this cable. It is very well built. Yes, it's heavy, but that's because it's got lots of copper. It comes with a nice carrying handle making it easy to cary around.
     
  7. Cosmacelf

    Cosmacelf Active Member

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    If you want lighter, build your own with only three conductors. It won't be a 14-50 extension cord, but it will work for Tesla charging. Alternatively, there is a company that will modify your UMC to give it a seamless 50' cord length.
     
  8. linkster

    linkster Member

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    #8 linkster, Jul 22, 2015
    Last edited: Jul 22, 2015
    Sorry, none.

    Remember, you SHOULDN't charge at more than 32A from oven/range 14-50's since 98+% are wired with 8-3 Romex deploying a 2-pole 40A breaker.

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    +1 @$249
     
  9. steilkurve

    steilkurve Member

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    Not an expert but news to me. I've charged on an oven before and it did give me 40A. Could have been part of the 2%. But if it does deliver 32A, leaving the car at 40 is a problem? Won't it just pull 32 then. Sorry if it's a dumb question.
     
  10. NigelM

    NigelM Recovering Member

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    #10 NigelM, Jul 22, 2015
    Last edited: Jul 22, 2015
    Quite likely that you got 40A from an oven that was wired/had a 50A breaker. See my note above, it's perfectly safe to draw 32A off a properly wired 40A circuit.

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    Modify the UMC to be 50' and you have the inconvenience of unrolling and repacking 50' every time you use it. An extension cable is there only for the occasions when you really need it.

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    I also keep one of these in the trunk 'footwell'. It's heavy but very well built.
     
  11. mknox

    mknox Well-Known Member

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    I bought a 50' version of that one (or one like it). It weighs a lot and you really need two people to coil it back up when you're done. I have needed the full 50' on at least two occasions, so not much of a choice, really.
     
  12. steilkurve

    steilkurve Member

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    Ok. Tx. So I don't have to play around with the amperage. If it's a 50 breaker, it'll automatically give me 40. Likewise, if it's a 40 breaker, the car will dial it down to 32. No manual intervention needed?
     
  13. mknox

    mknox Well-Known Member

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    No. If you use your NEMA 14-50 adapter on your UMC it's going to assume you have a 50 amp circuit and set the car to 40 amps by default. If you plug in to a stove 14-50 outlet that's been wired to a 40 amp breaker, you need to manually dial the car down to 32 amps (80% of the circuit rating for "continuous" loads).
     
  14. linkster

    linkster Member

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    The above statement is completely false.

    The UMC/"S" receives the charging limitation information from the UMC adapter and it cannot "see" upstream (wire gauge nor breaker size).

    btw, I will be glad to put the inconvience of unfurling my lightweight 50' UMC (that I keep in the car for trips) up against your bulky, heavy, overkill 50A extension any day. There is just no reason to carry a 50A rated extension when the UMC only has a 40A rating.
     
  15. mknox

    mknox Well-Known Member

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    I agree, and if I'd known about the retrofit I'd have gone that route myself.

    Are you sure about the 40 amp rating, however? I know electrical codes require that circuits running "continuous loads" operate at a maximum of 80% of the rated capacity. That's why we can only pull 40 amps from a 50 amp electrical circuit. I assumed, perhaps incorrectly, that the same would apply to the UMC itself.
     
  16. NigelM

    NigelM Recovering Member

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    Looks like one of my fellow members disagrees with me about manual intervention. But if in any doubt change the setting inside the car to a max of 80% of the breaker size. See FlasherZ's great FAQ here.

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    I'm certain I've seen it but as this is a safety question, I'm not going to argue with you. OP should double check that his settings are max 80% of the breaker size.

    Next time you're in FL. My point was that you have to unfurl your 50' every time you use your UMC, I only have to unfurl my extension cable once or twice a year when I need it.
     
  17. steilkurve

    steilkurve Member

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  18. linkster

    linkster Member

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    mk

    Flash will be more specific, but it doesn't have to follow the the same rules since it is outside (cools better) the wall with its (4) 12 ga. and signal wires. I think the HPWC only has 6 ga. for L1 and L2 (correct me if i'am wrong) but we all know its not just about the gauge but also the jacket material (and if it's liquid cooled :biggrin:).
     
  19. bollar

    bollar Disgruntled Member

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    That cable is 20 ft vs. 30 ft on the other reference cable.

    As for what will happen if you don't dial down the amperage? That will depend on the wiring on the circuit, the size of the circuit breaker, the age of wiring and possibly some other things. Scenarios range from:

    - Nothing bad happens
    - Breaker trips constantly (pulling more amps than the breaker rating)
    - Burning the house down

    At the very least, I'd verify the circuit breaker's rating and set the car to 80% of that if it's less than 50 amps.
     
  20. LetsGoFast

    LetsGoFast Active Member

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    The best case scenario when you draw more current from a circuit than it is rated for is that it trips the circuit breaker and shuts off the charge. The worst case scenario is that overloading the circuit starts a fire (and burns down the rest of the city like Mrs. O'Leary's cow didn't actually do). In between those outcomes, you might do some heat damage to the receptacle or wires that requires attention from an electrician to repair before you can use the stove again. There is also some chance that you are protected from yourself by the safety margins envisioned by the people who designed the code and you manage to draw more power than the circuit is rated for and nothing untoward happens, but it isn't a risk worth taking for a slightly faster charge.
     

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