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Advice needed: NEMA 14-50 outlet install

Discussion in 'Model S: Battery & Charging' started by ny888, May 11, 2015.

  1. ny888

    ny888 Member

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    I had 2 electricians come to give me quote. My panel is full, all breakers used. Only other heavy load is electric dryer, my range is gas. No a/c. Panel to outlet would be about 40-50 feet. One electrician says he can most likely double up and not need sub panel. Other one quotes with sub panel. Quotes could not be more disparate. 1st one is $500 and the other one is $1325. How can they be so different?
     
  2. Chris TX

    Chris TX Active Member

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    Look into using duplex breakers. They can take an existing pair of breakers and add another pair. No need for another panel.
     
  3. Tdriver

    Tdriver Member

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    Some companies have a history of going for top price hoping you don't get other quotes......a lot of people don't get a second quote.
    I just got three quotes for a wall connector and some low wattage outdoor outlets.....$3500, $1650, $850. The low guy is doing a nice clean job and is licensed.
     
  4. Cosmacelf

    Cosmacelf Active Member

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    When the electrician said "double up" presumably he meant swap out some breakers for double density ones? If that's what he meant, then that's a good way to go. Price sounds good.

    The second electrician just quoted a different way of doing the work that is more expensive.
     
  5. ny888

    ny888 Member

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    What gauge wire should I use, 6 or 8? Electrician feels 8 is enough but up to me.
     
  6. RandyS

    RandyS Fan of Elon

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    I've seen #8 wire used in 40 amp charging circuits and the conduit gets pretty warm when charging for a long time...Plus, you have 40 or 50 feet of extra length thrown in...If it were me, I'd use #6 wire...The extra cost doesn't amount to much...
     
  7. 647chang

    647chang Member

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    I used 6 gauge, and with parts and everything it run me a little over $200, that includes cutting and patching all the holes in the wall. Took me a whole day to do it. As long as they are licensed, you shouldn't have to worry.
     
  8. linkster

    linkster Member

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    I would double up by using narrow/GE or piggyback/Square D or similar type breakers to make room. I would use a 50A breaker and pull 6-3 (includes a bare ground) NM-B (romex) or 8 ga. THHN (in conduit) for this branch circuit.
     
  9. Moonwick

    Moonwick Member

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    I'd definitely go with 6ga, especially if you're going more than a few feet. 8ga will get pretty warm after a few hours of carrying 40A; all that heat is energy that could be going into your battery instead. ;) It's worth noting that the S is relatively sensitive to voltage drops and will turn down the amperage if it senses that your wiring is being pushed a bit too far. Using 6ga instead of 8ga over a significant distance like you're planning will probably save you some headaches where the car throttles back the amperage due to other loads (like AC compressors and so on).
     
  10. No2DinosaurFuel

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    I don't know... But my electrician gave me 10 or 12G wires for the 240V for my 30A electric car charger. It was running around 10 feet or so. Is that too small gauge for that length? I eventually will be moving to the HPWC and have room enough to get 100A breakers on my service panel. What is the wire rating for 80A or 100A?
     
  11. Lloyd

    Lloyd Active Member

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    Here is a good reference for wire ampacity:

    http://www.cerrowire.com/ampacity-charts
     
  12. ibdb

    ibdb 3 Car Garage and a 5 Car Life

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    Telsa recommends 6G on their site. I'm inclined to trust them.
     
  13. chriSharek

    chriSharek Member

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    I installed the 50-amp dual pole breaker, 90 feet of 1" conduit and #4 gauge wiring this past weekend for my HPWC (link below). The price difference between the #4 and #6 was a penny per linear foot, so I opted for the #4. If you're just installing a NEMA 14-50 I'm sure #8 would work fine.

    Preparing for my baby - HPWC Install
     
  14. No2DinosaurFuel

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    THanks. I guess I should be fine. But it is the limit though. Thinking now, the length is probably closer to 5ft or so with solid copper core with teflon coat with metal shield. He is a certified electrician so hopefully he knows what he is doing. hahah. I did bring the wire gauge up as a concern, but he said I should be good for such a short wire run.
     
  15. linkster

    linkster Member

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    10ga. is needed for 30A (24A continuos) which is what I have been using for nearly 50K miles.
     
  16. KJD

    KJD Member

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    The Tesla home charging FAQ has some good information on that.
    FAQ: Home Tesla charging infrastructure QA
     
  17. davewill

    davewill Member

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    Most 30a EVSEs actually charge at 30a, and require a 40a circuit. That would require 8ga wire. What EVSE are you installing?
     
  18. Cosmacelf

    Cosmacelf Active Member

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    The wire gauge needed depends on what kind of wire you use. Typically, wire run in a conduit will be fine with 8 gauge, but romex wire not run in a conduit is going to need 6 gauge.
     
  19. linkster

    linkster Member

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    #19 linkster, May 12, 2015
    Last edited: May 12, 2015
    Opps! You're correct! I was thinking UMC and not EVSE. (now where is the delete previous post button?):cool:
     
  20. No2DinosaurFuel

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    I am using the bosch powermax 30A charger. I forgot the exact model number but it is the common one on amazon.com
     

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