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HPC Electrical Cable Size

Discussion in 'Model S' started by ibcs, Mar 5, 2012.

  1. ibcs

    ibcs Member

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    I'm will be adding wiring to the garage for the HPC for the Model S. I can't find the exact specifications for the new HPC. I have two wiring choices that I have found both from Belden. I also need to know the number of conductors is it 3 plus shield or 4 plus shield?

    Belden C5601 - 85 Amps per conductor at 30 degrees C.
    Belden 27264 - 95 Amps per conductor at 25 degrees C.

    Any thoughts or comments would be greatly appreciated.

    Thank you
     
  2. Doug_G

    Doug_G Lead Moderator

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    Model S can reportedly draw 80A, and you need a 20% margin, so I think even 95 is borderline.
     
  3. dsm363

    dsm363 Roadster + Sig Model S

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    Are you doing the wiring yourself on a project before your Model S will arrive? If you're working with an electrician, they could always help you out. Once the HPC is released, the will include an install sheet for the electrician with the needed details and specs.
     
  4. ibcs

    ibcs Member

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    I have an electrician ready for the assignment. I have a contact within the wiring business that can get me the needed wire given enough lead time. This wire is $1.50 - 2.00 per foot and I'll need 65 ft. to complete the job. Just trying to plan during the painful waiting time for delivery.

    I was just hoping that the HPC specs were available and I'd missed them.

    Belden C5611 is #3 wire rated for 104 Amps at 25 C
    Belden 27896 is #3 wire rated at 110 Amps at 25 C.

    Thanks for the input.
     
  5. dsm363

    dsm363 Roadster + Sig Model S

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    If I can ask, what aproximate reservation number are you? I think you'll have plenty of time to get everything done in time for your car even if you are one of the first Signature deliveries.

    Check this out
    http://webarchive.teslamotors.com/display_data/home_connector_installation.pdf

    This should at least give you a starting point to discuss it with your electrician. I just wouldn't finalize anything until the new HPC is released. Good luck.
     
  6. ibcs

    ibcs Member

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    Signature #121 - Yes, I have time, but I sure hope not much more time.
     
  7. vfx

    vfx Well-Known Member

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    Copper keeps going up!
     
  8. dsm363

    dsm363 Roadster + Sig Model S

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    Awesome. You can probably schedule an appointment with your electrician to make sure they are available in early July. Hopefully Tesla will send out HPCs ahead of the car for people that order it so you can get it installed.
     
  9. Robert.Boston

    Robert.Boston Model S VIN P01536

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    So, worst-case scenario: your actual voltage is 208v. The twin chargers pull 20kW, so you have 20,000/208 = 96A. With the 20% safety factor, the gear should be rated to 115A.

    More likely is that actual voltage is not below 220v, so you'll draw 20,000/220 = 90.9A and should have gear rated to 109A.

    So, if you really want to order now before we have the spec sheets, I'd go with Belden 27896 is #3 wire rated at 110 Amps at 25 C. It's probably overkill, but unless you have a long run, the extra cost is small (and, if you have a long run, you should want the better wire anyway).
     
  10. Doug_G

    Doug_G Lead Moderator

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    Judging by the Roadster, the power is limited based on amps, not power, so you don't need to factor out the voltage. My understanding was that the Model S HPC draws 80A.
     
  11. ibcs

    ibcs Member

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    Thanks Robert,

    I'm still working out the placement of the HPC, but it could be 65 ft. In that case, I want to have the heavier wire. I will probably wait until we get final word. A friend of mine works for Belden, so I might me able to get a decent deal. As someone stated, copper is going up and up lately.
     
  12. Beavis

    Beavis Signature 991

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    So, are the install instructions on the website not for the HPC?
     
  13. Doug_G

    Doug_G Lead Moderator

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    They are for the Roadster HPC, which is different.
     
  14. Beavis

    Beavis Signature 991

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    I guess I just assumed that the set up would be the same. Glad I didn't start on that project yet.
     
  15. Doug_G

    Doug_G Lead Moderator

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    The Model S reportedly will be able to draw a little more power from its HPC than the Roadster can.
     
  16. dsm363

    dsm363 Roadster + Sig Model S

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    Yeah. Sorry for confusion. I just put up Roadster HPC as an example of what they'll likely post for your electrician to install the Model S HPC. It should be similar but Doug is right, the new HPC can draw more power. I believe it can deliver up to 80A.
     
  17. ibcs

    ibcs Member

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    No confusion. I'm thrilled with everyone's input. I now know that I need #3 wire which is a little more expensive, so I want to shop for the best price available.

    Thank you for everyone that has added to the discussion.
     
  18. dhrivnak

    dhrivnak Active Member

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    I installed my own HPC for the Roadster and I used 6 gauge wire. It uses two power wires and a neutral for a total of 3 wires. With a 35’ run the wire is fine at 70 amps. With the longer run and higher current you may want 4 gauge wire. Then remember due to de-rating you will need a 100 amp breaker for the 80 amp circuit. Check around as I was able to get 3 conductor 6 gauge for $2/ft that worked very well.
     
  19. Lloyd

    Lloyd Active Member

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    #19 Lloyd, Mar 5, 2012
    Last edited: Mar 5, 2012
    If I remember correctly it uses two hots and a GROUND, not a neutral. The neutral is left unused in this application. I used #4 wire for a 6' pull. #6 is insufficient if you put it behind a 100 amp breaker as suggested. See below

    http://www.armstrongssupply.com/wire_chart.htm
     
  20. hcsharp

    hcsharp Active Member

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    That is correct. If you are going 65' you will need #2 aluminum or #3 Cu.

    For the Roadster you should not use #6 for the HPC. You should use #4 Cu. You are supposed to size the wire for the breaker, not the device. Regardless, #6 is insufficient even for 70A unless the insulation is rated for 90 deg C or greater and exposed to air, not behind a wall, etc.
     

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