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Dual Tesla HPWC Installation

Discussion in 'Model S: Battery & Charging' started by SSonnentag, Jul 20, 2018.

  1. SoCalNick

    SoCalNick Member

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    Yeah, I'm confused about the Data Cable also.
    From reading Appendix B of the HPWC manual, they say...
    • The signal wire should be in it's own 1/2" conduit.
    • If you run the signal wire in the power conduit, the insulation rating of the signal wire should be equal or greater than that of the power wires. (I have no idea how to check that.)
    • They also say to use twisted pair, and recommend shielded cable.
    As a network / infrastructure wiring consultant, I deal with network data cables a lot...
    Firstly, we can easily get Cat6 Shielded Twisted Pair cable, but the HPWC only uses 1 pair, whereas a network cable contains 4 pairs.

    I have seen many people "double up" these cables to make a "better connection" but that is now how twisted pair works - the whole point behind twisted pair is that the send and receive pairs are twisted together, so that the crosstalk between the two is neutralized.
    If you use the white/orange, orange/white pair alone, you will get better signal than if you use both orange cables in D+ and both brown cables in D-.

    Secondly, the shielded cables need to be connected/grounded to something or the EMI will produce the same interference in the shield, that will then be transmitted to the signal pair. There is no ground in an HPWC, only a neutral, and I don't think we should be connecting the STP cable to that.

    SSonnentag did a great job of routing the data cable through a separate conduit, which I think is overkill, but certainly will get the best results.

    Last dumb question.
    The instructions say to set the rotary switch to "1 to 8" on the master, depending on the amperage of the circuit. That only allows for a 50A circuit, as anything higher uses "9 through D". I'm hoping that this is just a typo.
     
  2. Rocky_H

    Rocky_H Active Member

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    That is false. It does use ground and does not use neutral.
     
    • Helpful x 1
  3. SoCalNick

    SoCalNick Member

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    Yes, you are correct; my mistake.
     
  4. TechVP

    TechVP Active Poster

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    Back to the HPWC CAT communication cable wire minimum specifications, does anyone know if this has been covered in another thread?
    -TechVP
     
  5. TechVP

    TechVP Active Poster

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    This comes from the specification of the wire that is chosen. In my case, the wiring is THHN. The specification for THHN cable is 90 deg. celcius. Therefore, a Tesla HPWC comm wire installed in the power conduit has to match or exceed that rating.
     
  6. TechVP

    TechVP Active Poster

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    #26 TechVP, Oct 2, 2018
    Last edited: Oct 2, 2018
    A bit of digging, and I believe I have a solution to the cable dilemma . Belden 1120A appears to meet all the criteria above.
    If you agree with this selection, send me a Thumbs Up.

    Here is a link to a vendor that will sell a 50 foot minimum for $25. Shipping is extra, so budget $1 / foot to be safe.
    Belden 1120A 18 AWG 1-Pair Shielded Tray Cable, 600V

    Here is the Technical Specification for Belden 1120A
    https://www.wireandcableyourway.com/uploads/file/1120A Technical Data Sheet (English).pdf

    Amazon has a vendor that carries this, but it is quite expensive. Check the vendor link above which is quoting 0.50/ft and is in stock.

    And here could be an alternate for the budget minded. Specs seem favorably similar. Can be bought by the foot.
    #18-2C THHN-PVC Shielded Tray Cable

    -TechVP
     
    • Like x 1
  7. SoCalNick

    SoCalNick Member

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    Seems like the ideal cable - good work.
     

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