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Anybody use Aluminum wire to their NEMA 14-50 outlet?

Discussion in 'Model S: Battery & Charging' started by Barry, May 7, 2014.

  1. Barry

    Barry Member

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    Has anyone used Aluminum electrical wire for their charging outlet? I live in a mixed-use building (condo with commercial on first floor), so use of Aluminum is permitted. A neighbor told me the cost of aluminum conduit is about 25% that of copper for an equal current rating. I'm aware of the problems in the 60s and 70s related to aluminum wiring (not accounting for different coefficient of expansion than copper and galvanic corrosion at the termination.) As those problems have been addressed, any reason not to use it?
     
  2. ElSupreme

    ElSupreme Model S 03182

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    Unless you are running a really long way, #8 (or #6) Cu isn't all that expensive. I would rather spend the little bit more on Cu than to try do deal with the thicker and stiffer Al. #8 Cu is already hard to deal with inside a j-box for the 14-50R.
     
  3. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    I wouldn't doubt if some said they did, but typically I've found that for #2 or smaller, CU is really the best choice and isn't too much of a difference price-wise, all things considered (labor, materials, etc.)

    You only need #6 AL for a 14-50 if you wanted to use it, so in many cases it's not bigger than what's already considered (#8 CU is sufficient for wire-in-conduit, not Romex) and it's more of a pain in the ass to deal with.
     
  4. sfriedrich

    sfriedrich Member

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    I'm an all copper man, here; especially for high power circuits.
     
  5. CliffG

    CliffG Member

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    Yes, and we used #4 Al - and the difference in pricing for #6 Cu was in the hundreds of bucks for the 100+ ft. wiring.
     
  6. ghost640

    ghost640 Member

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    Can I ask a sort-of related noob question - what's the difference between 14-50 and 14-50R? I just went to the hardware store to buy one - my Tesla pamphlet says 14-50 but the store just had the 14-50R.
     
  7. ElSupreme

    ElSupreme Model S 03182

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    14-50R stands for the 'R'eceptacle, or the female end.
     
  8. Barry

    Barry Member

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    I'm not familiar with all the details of the building mechanicals, but the main electrical room is about 300 ft from my assigned parking spot in the building. There may be a closer access point and I'll have to find out details from building maintenance when the time gets closer (I have a MX rez, so it will be a while).
     
  9. brucet999

    brucet999 Active Member

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    Look up ampacity tables online. Normal wire sizes called out for a given sized outlet are predicated on 100 ft of wire distance from the panel (or less) allowing no more than 5% voltage drop from line resistance. Your 300 foot run will require larger wire to reduce the line losses. Remember, you are delivering watts to the onboard charger, so even though the amperage will remain at 40, lower voltage from line losses will reduce the number of watts delivered and therefore increase the time required for a charge.
     
  10. Barry

    Barry Member

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    A thread from the past :smile:

    I went with copper. First, the electrician said if aluminum is used, the connections need to be inspected every year, tightened, etc. Second, the HOAs insurance policy would need to be amended if aluminum was used. Bottom line, too much hassle, despite potnetial cost savings.
     
  11. Cyclone

    Cyclone Active Member

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    Meanwhile, congrats on the 85D. Still going to get a MX, or did MSd sway the decision?
     
  12. Barry

    Barry Member

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    My primary reason for reserving an X was for the AWD. Being an empty nester, I really didn't need an SUV any more, and I wasn't thrilled with the doors on the X. When the D event happened, I cancelled my X rez and ordered the 85D.
     
  13. Cyclone

    Cyclone Active Member

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    Cool. Glad you won't have to run another outlet for a second vehicle then!
     
  14. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Aluminum is fine to use, you can use #6 for a NEMA 14-50 (50A at the 75 deg termination). You need to make sure to use CoAl rated devices (most are at that gauge). Some people will recommend some older mechanisms to help cope (anti-oxidation paste) - and some inspectors will even require it - but today's aluminum really doesn't need it.

    There are a lot of people scared about aluminum wiring, which was warranted when considering the 1970's 2000-series aluminum used in wiring (they basically took long-haul high tension cable aluminum and made solid building wire out of it). Today's 9000-series aluminum wire is much closer to the expansion/contraction rates of existing copper wire. In addition, since larger wires are stranded, you have more protection against a single strand that works loose - you really don't have to re-torque it anymore than re-torquing copper.

    Now, with that said, the copper will run cooler and at that gauge the price difference isn't too much; I recommend copper (and Tesla requires its "find an electrician" program electricians to use copper), but it will be ok.

    For the HPWC, you run into a problem because you have to use #1 AL for a 100A circuit and you won't be able to work that into the HPWC terminals. You're best to use aluminum and transition to #3 copper in a junction box near the HPWC with listed connectors if you have a longer run.
     
  15. hanstremblay

    hanstremblay Member

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    I use AL for my HPWC at 80A on a 100A breaker for one year now alu.jpg
     

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