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18awg wire for HPWC Master/Slave

Discussion in 'Model S: Battery & Charging' started by Naonak, Apr 13, 2017.

  1. Naonak

    Naonak Member

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    Location:
    Kansas
    I have installed a second HPWC in my garage and I'm upgrading my circuit to a 100a to feed both chargers. I plan on putting the signaling wire between the two - the manual calls for an 18awg TP shielded wire.

    Does anyone know what the best wire to use for this is? I have tons of CAT5e and CAT6 wire around, but it's all 22 or 24 AWG. Looking into 18AWG wire, I find that the TP variety is unreasonably and ridiculously expensive, whereas the non-twisted version is super cheap. What kind of signaling is going through those wires and does it really need a twisted wire? Is the signaling that fragile that a little interference is going to cause it to fail?

    Any experience that people have with the install of multiple HPWCs would be great, or any suggestions on how to proceed!

    Thanks!
     
  2. GRiker

    GRiker New Member

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    I used shielded CAT-5 and it's worked well. Far less expensive than single-pair twisted/shielded. Attach the drain wire (shield) to ground on the master end only. It's a data connection (RS-485, I believe), so 22 or 24 AWG is fine.
     
  3. Naonak

    Naonak Member

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    Awesome, thanks for the info. I appreciate it.
     
  4. DarkMatter

    DarkMatter Member

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    If anyone in the future wants to use 18 AWG single twisted pair, it's often marketed as in-wall speaker wire. Any low-voltage installer will have it on hand which is probably why Tesla specifies it. Belden 5300UE would be a good example. Not all in-wall speaker wire is twisted but the good stuff is. I'm certain any Cat3+ or similar should also work well, and if you're paranoid you can group up the pairs to get the equivalent of 18 AWG.
     
    • Informative x 1
  5. Fiver

    Fiver Member

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    We used outdoor rated Cat 6 on our install for singaling. (3 chargers on single 100amp line, install was outside).
     
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  6. boaterva

    boaterva Supporting Member

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    It may be they specified 18AWG because of the max length of 49 feet for the data run. Mine was about 20' and I'm pretty sure the installer didn't use 18.
     
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