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New Wall Connector :)

Discussion in 'Supercharging & Charging Infrastructure' started by pluginx007, Apr 12, 2016.

  1. AZ Desert Driver

    AZ Desert Driver Rare combination

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    I just re-read the 300+ instructions/comments on the The home Tesla charging FAQ is located HERE. Great work. Thanks.
    But I am now cross eyed... My install is to an attached garage.
    Seems like the hang up is the simple 120 volt branch circuit . One guy said he could run 6,6,6-10 in a conduit for the 14-50, but he would have to run another pair of wires in that same conduit to supply the 120VAC socket. He would install a new 50 amp breaker in my main panel, and make that breaker a dual 50/20 amp to fit into the slot. No sub panel in my garage - just the 14-50 socket (and the 120 outlet).
    Another one said he could run 2,2,2,8 from a new 100 amp breaker to the garage sub panel and use 30 inches of NM from wall penetration at 18" to the panel at 48". He said if I asked for a HPWC, he could not install, but if I stated I only wanted a single 14-50 and 120 outlet, I'm good.

    is it true that adding a 120 v outlet from a 2,2,2,8 system causes a problem?
     
  2. FlasherZ

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

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    First, we have to get terminology right... there is no such thing as a "2,2,2,8 system", so I'm making some assumptions based on what they're telling you.

    You cannot attach a 15A or 20A receptacle to a circuit provided by a breaker that is larger than 20A, so you can't connect the 120V loads directly to the 2/3 feeder coming from the main panel. That's why you need the subpanel - to provide the protection for the branch circuit.

    For a wall connector, it's that 30" of NM cable that gets you in trouble. 2/3+G NM (which is basically 2/2/2/8) is only rated at 95A. This means a wall connector cannot be installed at the 80A charging / 100A breaker setting legally on that feed. Technically, you can use the 2/3+G NM cable to feed a wall connector plus 120V loads, *but* you could not have it at the 80A charging/100A breaker setting - the maximum you could have is probably the 64A (80A breaker) charging setting, which leaves you 15A in feeder calculation room for a 120VAC circuit.

    As an option, the running of two circuits in the same conduit will be okay, provided it's done using #6 wire-in-conduit for the charging plus #12 wire-in-conduit for the 120VAC. Running two circuits in the same conduit means you'll have to de-rate the wire capacity using a 0.8 factor because there will be more than 3 current carrying conductors in the same raceway. However, #6 will work ok for the charging circuit as a 90 degC conductor is good with de-rating to 60A (75A for 90 degC * .8 = 60A), and you only need 50A rating for a 40A charging load. Your 120VAC circuit rating will be a maximum of 16A with #12 wire, so you can put a 20A breaker on it (but cannot put 20A receptacles on it). You would have to pay attention to conduit fill, but it should be okay.

    My own preference would be to install a subpanel in the garage. It gives you a disconnect and it gives you a place to land future load-sharing wall connectors later. I would try to run conduit the entire way instead of using NM cable.
     
  3. AZ Desert Driver

    AZ Desert Driver Rare combination

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    Boy - simple stuff is not simple. Thanks for the guidance.
    Because two different bidders said they had to make the 18" wall penetration a junction box, and switch from #2 wire to NM for that final 18"..I thought running conduit the whole way without a splice was outlawed.
    So now I'm thinking of running up to the roof and then along the parapets, drilling through the roof and dropping down into a sub panel .
    My end game is a single 14-50 for a MS and a 120v for the garage load, including a fridge and light duty workshop tools. Not planning on a HPWC. Figure if I get two teslas, we can charge sequentially off the one socket. Using the roof design, I don't trench my lawn. The roof design should let me have wire in conduit the entire length, with a few "junction boxes" as pulling access - but no splices.

    So - I think you said....#2 into sub panel where it begins with a 100 amp breaker and terminates in a 50 amp sub panel breaker. Then #6 into the 14-50 off the 50 amp sub panel breaker. I can also tap into the #2 wire in the sub panel and feed a 20a breaker with 120v. (how this is done is still escaping me). Can my garage load can be a 20 amp- 4 gang GFI socket?. (or did you say I could only mount a 15a GFI?). Or did you say I need to run a new #12 wire pair from a new breaker in the main panel to sub panel, installing a 20 amp breaker in sub panel and then off into the gfi sockets?. Do I run #6 or #2; do I run 6 conductors over the roof or do I run bigger wire and only 4 conductors and branch into my 120v. Boy - simple stuff is not simple. Am I overthinking this?
     
  4. ccutrer

    ccutrer Active Member

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    If you're dropping a sub panel on your garage, you run three conductors plus a ground to the sub panel, then three conductors plus ground to the 14-50, and two conductors plus ground to the 120v outlet. If you skip the subpanel, you run all five conductors plus two grounds in a single conduit, and you have to debate them (so #12 would only be good for a 15A receptacle, as @FlasherZ pointed out). Or you could go differently and skip the subpanel, but run the two circuits in separate conduits in order to avoid the derating.

    I also agree with @FlasherZ's recommendation - just do the subpanel. It's far more flexible in the long run. Even if you don't plan on charging two EVs at the same time, it would be a huge pain in the neck to swap which one is plugged in to a single outlet. With a subpanel, you start out with one, and if you decide that it's too much of a pain, you switch the 14-50 to a wall connector, and add another wall connector off the subpanel, rather than having to start over from the main panel (where your wire cost will be more due to linger distance; having to retrench if you go underground, or plain deal with another conduit either way).
     
  5. cscott

    cscott Member

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    Any luck with that? I live in the city and my charger is going to be accessible to the public but hardwired to my electric supply -- I'd love to have a simple option to enable/disable the charger only when I'm at home. It seems like that data I/O port ought to be able to do that...
     
  6. SmartElectric

    SmartElectric Active Member

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    You will likely find that no one else would use your charger. I cannot say I've ever seen or heard someone use a private charger that they didn't already negotiate with the owner to use...
     
  7. DMC-Orangeville

    DMC-Orangeville 85D and John Deere 5100E

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    If you feed your HPWC (or Nema 14-50) with a disconnect switch or spa panel switch, mounted beside the device, it's a simple matter to turn off the power, and lock off the switch. Example images below.

    heavy_duty_switch.jpg Spa Panel.jpg
     
  8. Rocky_H

    Rocky_H Active Member

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    He didn’t say not negotiated beforehand. Regardless, all of that depends on how you describe the listing on Plugshare. If it’s outside and just listed as available, then that would be really unreliable and frustrating for people to expect to use it but not know if it will be powered or not.

    In Twin Falls Idaho, there is a dentist’s office, where the owner has a Tesla. He got a 14-50 outlet installed at the office and offered it for sharing. For the listing, it just says to not come use it during regular business hours of Monday through Friday, 8-5, but evenings and weekends are free for people to use. Several Tesla owners used that for a couple of years before Twin Falls got a Supercharger. And I got to share my 14-50 outlet in my garage in Boise with a few people before we got a Supercharger here. I did include to contact me beforehand to arrange it, but the description also says that I can leave my UMC cord running out from under my garage door if someone asks, so they can use it even if I’m not home.

    So there are many flexible ways to do this.
     
  9. cscott

    cscott Member

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    So... my disconnect will be in my basement, next to my main circuit breaker box. I don't fancy a trip to the basement every time I path my car. And besides, I'm not *that* paranoid. I just want a little extra piece of mind, and having the outlet only turned on (say) midnight to six am would give that. We don't often have issues, but we have an apartment building next door and we somewhat frequently find folks parking in our space, especially around holidays. New Year's is the worst. And agreed, EVs aren't that common yet. Just planning ahead.

    And the longer story is that we have an additional four parking spaces adjacent that we rent out. We can deal with parking elsewhere for a while if someone's in our spot, but it's really bad if someone squats in a space that one of our renters is paying us to use. We'd like to eventually provide our parking space renters with the ability to charge at their spot... so we need to be able to exercise a little bit of control.

    In any case, my real question here was about the data I/O spec. I've seen third party chargers out there which offer a 12v "control" input to turn the charger on/off (without needing a hefty 60+A disconnect). I'd be happy if we understood the tesla interconnect wiring even just enough to do *that*.
     
  10. MP3Mike

    MP3Mike Well-Known Member

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    Depending on what you install, and local code, that may not be acceptable. Often times the disconnect has to be in direct line of sight and/or within a certain distance of the device. (Which is why you see disconnect boxes next to a lot of HPWCs that aren't installed in the garage/near the breaker panel.)
     
  11. Pollux

    Pollux Active Member

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    I just want to take a moment to thank the creator of this thread, pluginx007, and all of the contributors for the many clarifications and insights. Sadly, I am unable to wrap my brain around much of what is being said; apparently, my recent intelligence upgrade surgery has failed, leaving me with my original intellectual capabilities, to wit, those of a flatworm.

    That said, I rushed from my terminal to the backyard a few days ago to engage an electrician in conversation about the line he is running from my new-to-me (old) house to my new-to-me (old) garage. This conversation took place over a newly-excavated trench. Soon, perhaps that very day, there would be pipe and wiring! Excitedly, I began to question him about the details of the installation, including the line that they were proposing to run. #3? #4? I wasn't sure exactly what I was saying or asking, but technical terms I had recently read on this thread came tumbling out of my mouth, in somewhat random fashion. I still don't know what I babbled that morning. But we realized there was a major disconnect: despite my repeated requests for a connection capable of supporting 100A out to the garage (of which up to 80A for an HPWC), but which would run for the time being at a constant 60A due to the overall limitations of the power budget for the house, what was being installed was wiring to support a 60A circuit. Whoa!!! NOT what I asked for! Dunno how many times I had had this discussion, but here we were, at almost literally the last second, about to install a 60A-capable circuit instead of a 100A-capable circuit.

    New round of specsmanship by the electrical contractors, old materials gave way to new, and while I'm at it hey, let's toss in a handy sub panel (I really do try to pay attention to this thread!) rather than just a single circuit to the HPWC... today, they finished closing the trench after last Friday's inspection, the HPWC is up on the garage wall, and only a few steps remain tomorrow.

    THANK YOU, @pluginx0007, thread contributors, and TMC!!

    Alan
     
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  12. Ormond

    Ormond Member

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    I don't know why I'm reading these posts. It's all Greek to me. I might not be smart enough to have a Tesla. :)
     
  13. Pollux

    Pollux Active Member

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    If a flatworm can do it, so can you! :)
     
  14. Pollux

    Pollux Active Member

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    P.S. Acquiring a Tesla also regrows lost hair, causes unwanted hair to fall out, and adds an air of rugged mystery that all sexes find attractive.
     
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  15. HJD.

    HJD. Member

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    Long time lurker, first time poster...and soon to be X owner (and seriously contemplating adding an S to the mix too...).

    I've learned so much from everyone's insights and unique setups, and it's helped to inform my own wiring plans.

    I'd appreciate the community's feedback. Here's the situation:

    Waiting on delivery of our first Tesla. I live in a pretty new house (<5 years old). I have a atttached garage (connected permanent breezeway from house to garage) and I'm going to be running a 100A circuit to the garage for the Tesla, into a sub panel. My intent is to put 2 HPWCs in the garage and share the load across them. Each WC will get its own 100A breaker in the sub panel, just in case I need to power one down for any reason (thanks @FlasherZ for the helpful diagrams!).

    Why 2 WCs? Future proofing really...we'd like to get a second one if we can find a way to afford it, and I don't want to rip open drywall more times than I need to.

    Here's the question:

    In the interest of future-proofing / backup solutions, I was contemplating also putting in a NEMA 14-50 next to each of the HPWCs, and give them each a 50A breaker in the sub panel, BUT - I plan to leave the breakers off unless I need the outlets. I recognize that using the full 80A off the HPWCs I have no headroom on the #2 we're pulling in from the main panel in the house. The 14-50s will be used only as a backup in some unforeseen circumstance where the HPWCs are not working for some reason.

    Will this setup be okay from a safety perspective? Will it pass code here in Chicago? Any suggestions on further optimizing this setup? Essentially...I want to maximize my flexibility -- have 80A available to both WCs and have 2 14-50s without having to run more than the #2 I'm already going to pull from the house to the garage. As I mentioned, the 14-50s are purely for backup purposes and I don't plan on using them unless the WCs have an issue.

    Thanks!
     
  16. FlatSix911

    FlatSix911 Porsche 918 Hybrid

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    I had the same thought and added a NEMA 14-50 next to the HPWC... works greats for guests :cool:

    IMG_3843.JPG
     
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  17. HJD.

    HJD. Member

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    Nice setup...do you have any load issues / concerns? From the looks of it, you're running both on the same 50A circuit?
     
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  18. FlatSix911

    FlatSix911 Porsche 918 Hybrid

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    Yes, both on a 50A circuit with 40A continuous output ... one at a time only :cool:
     
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  19. Ulmo

    Ulmo Active Member

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    (Page 29 of manual for North America should say 1-D instead of the European 1-8 for the amperage setting dial.)

    I wrote a reference to your post with the following shortened URL https://is.gd/UmFjWA into the manual I received today with my new HPWC. It's hard to write the j but I managed it.
     
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  20. Ulmo

    Ulmo Active Member

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    #320 Ulmo, Dec 28, 2016
    Last edited: Dec 28, 2016
    Correction to my below quoted and reference post:

    I won't quote much, because as I skimmed my above post, it was pretty well and completely written, almost a how-to. This is just for my small nit correction to myself.

    I meant this one at Cal Tech in Pasadena (not Cal Poly as I incorrectly wrote): Free Destination Charging: 50x L2 80A Stations @ Caltech, Pasadena, CA

    Note that the above quote leaves out important ideas in the original message; please read the entire referenced message to get my ideas and plans more accurately. Basically, for the lazy, I said it's better to have different parking spots for different types of proprietary connectors, and then eventually when there are enough EV's that the connector types can overlap (near 100% market penetration of EV's), they can go ahead and start overlapping the connector types. This widespread methodology of implementing charging spots with high parking space coverage also requires a more liberal policy at such parking spots toward letting ICE cars park in charging spots. This could be managed some way, such as having a "preference" for EV's at those spots. It would be a bit first come first serve. One way to automatically make these available more often than not is make them further away from the buildings they serve, kind of the reverse of the premium parking spot idea of current charging location incentives. Most premium owners such as Tesla like to park far away to protect their investments, whereas the Leafs, Bolts, etc. like to park nice and close, so the spread could be more in that format, overall. This changes with Model 3, so putting a few reasonably close generalized Level 2 (J1772) chargers closer to the building would be perfect (see the Cal Tech reference for a great way to do that!). Nothing's set in stone, of course. Just good ideas to contemplate while designing charging options.

    I like the idea of destination chargers having a low fee for use, that is close to at-cost, since it means no one will be stealing from anyone else (excess free benefit, excess costs for a charge, etc.). I hope low-fee accounting methods exist for this. Does anybody know, for instance, the overhead cost of ChargePoint? I really like their interface. (As opposed to EVGO whose interface generally sucks since you have to call in a lot when you sign up, and signing up can't be done in advance of EV purchase, because it's not low cost to get an EVGO card sent, unlike ChargePoint which has a fairly sensible fee structure for early startup.)
     

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