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DIY NEMA 14-50 Install

Discussion in 'Model S: Battery & Charging' started by Uricasha, Feb 25, 2017.

  1. Uricasha

    Uricasha Member

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    #1 Uricasha, Feb 25, 2017
    Last edited: Feb 25, 2017
    It is my hopes that this thread will serve as an informative discussion of how I installed my own Level 2 Charger. As a very important disclaimer, nobody would ever recommend that you work with electricity unless you have a full 100% understanding of how it works, and most importantly that touching live wires can cause death or serious injury. In light of that, use a licensed electrician to install your Level 2 charger. One more thing, I'm not a professional so don't take the practices I use here as elusion to doing it correctly.

    1. Permitting
    • I live in the City of Phoenix; therefore, my first step in this whole process was to apply for building permit, more specifically. "Minor Electrical Work". For the City of Phoenix, this type of permit can be applied for online without any electrical plans at this website. The cost for this permit was $250.
    • The City of Phoenix defines Minor Electrical Work as "The addition of of one or two new electrical branch circuits not to exceed 60 amps at 120/240 volts, single phase." For this application, I am installing one 50-amp branch circuit which is the recommended circuit rating for a NEMA 14-50 plug which can supply 40 amps/240v to your Tesla. More on this later. See Tesla's Mobile Connector information page here.
    2. Materials

    All of this stuff can be ordered from Home Depot/Lowes/Amazon. Links are included to give you a reference.
    • Corded Mobile Connector ($520 US) - Dedicated for garage. I plan on moving in the next couples years and having a universal NEMA 14-50 outlet would be more valuable to non-Tesla fan boys such as ourselves :)
    • Cable Organizer ($25 US) - Tesla's OEM cable organizer that allows you to neatly hang the cord on the wall
    IMG_3831.JPG
    • NEMA 14-50 Outlets - Qty:2 ($17.98 US) - I have a two car garage so all the outlet related items will have a quantity of 2.
    • NEMA 14-50 Outlet Wallplate - Qty:2 ($14.78 US) - I believe these may be cheaper at Home Depot. However, getting it delivered to my door is just as nice.
    • 2 Gang Outlet Box - Qty:2 ($12.18 US)
    • 50 amp Breaker ($9.47 US) - There are multiple main service load center types that take different types of breakers. Make sure you buy the same breakers as you currently have in your service panel. There could be a lot discussed on breaker interchangeability.
    • Heat Shrink Tubing - ($7.97 US) - Used for connections in conjunction with electrical tape when splitting the circuit.
    • Clamp Connector - ($15.96 US) - These are used at the junction box that splits the line going from the breaker panel to the NEMA 14-50 outlets.
    • 6" x 8" inch junction box - ($17.68 US) - Junction box for splitting the line going from the breaker box to the two NEMA 14-50 outlets. This box may seem big but I am using some pretty heavy gauge wire so it was nice to have the room.
    • Electrical Tape - ($4.26 US)
    • 6-gauge wire - ($160 US) - 75 feet for my installation needs.
    • Split Bolts - Qty: 6 ($33.76 US) - Used to splice the 6 gauge wire in the junction box. You could also use a copper wire clamp for this connection.
    3. Tools
    4. Electric Service Panel

    • This is the most dangerous part of the install. The first thing I always do prior to accessing the innards of the panel is to open the main disconnect to the panel. After I open the panel, I check for voltage with my non-contact voltage tester. Anytime my hands ever go near this panel, I always check for voltage, even if I checked it two minutes earlier. As a rule of thumb for myself, anytime I touch a wire, I always check for voltage. Well enough with the disclaimer, here are some pictures of the panel with the breaker installed
    IMG_0390.JPG IMG_0391.JPG IMG_0393.JPG IMG_0395.JPG
    • With the 75 foot roll of 6 gauge wire, I started in my attic. Directly above my service panel in the attic, there were wires coming up between the inner drywall and the stucco outer wall. Since this wire is so thick, I simply straightened it and blindly routed it from the attic down to the service panel. As you can see from the photos (more specifically photo 4), there wasn't much room in the service panel openning to receive the 6 gauge wire I shoved down from the attic. To make it a little easier, I cut a 6" x 6" hole in the drywall directly opposite of the service entrance openning and I was able to easily receive the 6 gauge wire from inside the house then push the wire outside towards the service entrance openning. I pulled a couple feet of wire through the service entrance wire openning and followed the same wire routing method that the service panel already had.
    • To connect the wires to the circuit breaker, I stripped approximately 1/2" of insulation from the wire thus exposing the copper wires. Then insert the bare copper ends into the circuit breaker (photo 3) and tighten until its really snug. (There is a torque spec for this, but this is what we call good ol american cowboying). It doesn't matter which wire goes into each hole as long as they are the black or red wires....
    • For the white wire and bare ground wire, I just connected them to the ground rails in the panel. I have read that the neutral and ground bars should be separate but the person who wired this before me did not split them out and the City inspector didn't seem to care either.
    • Since I now had a new breaker, I had to knock out two of the tabs on the cover panel and label the breaker.
    • From here, we are done with the service panel connections. I opened the breaker to the wires I just installed, put the cover on the service panel, then shut the main disconnect to the panel so that my girlfriend could make me dinner. :)
    • As always, I ensured the wires did not have voltage by checking with my non-contact voltage tester after I opened the breaker.
    5. Attic
    • Because I'm using non-metallic sheathed wire (NM-B), I simply rolled the wire to the junction box in the attic.
      • In the picture below, the wire on the left is coming from the breaker/service panel. The other wire on the bottom of the junction box and the one on the right are going to the two NEMA 14-50 outlets in the garage.
    IMG_0004.JPG
    • To setup the junction box, I secured it to a sturdy piece of wood and attached 3
      clamp connectors

      to accept the 6 gauge wire.
    • For the wires going into the junction box, I routed the wire through the clamp connectors and left approximately 12" of wire to play with in the junction box.
    IMG_0007.jpg
    • To attach the three 6 gauge wires, I had to use two split bolts, one piece of heat shrink tubing, and lots of electrical tape. I did this for all three 6 gauge wires, 120v red, 120v black, and neutral white. For the green ground wires, I used a twist connector and electrical tape. The ground wire was also attached to the junction box.
    • Now, I routed the rest of the electrical wire from the junction box to the two NEMA-14-50 outlets in the garage by going down in between the walls.
    6. Garage / NEMA 14-50 Plugs

    • To cut the holes for the NEMA 14-50 outlets, I used the "2 gang outlet boxes" as a template then used the drywall saw to cut a neat rectangle in the drywall.
    • The 6 gauge wire were routed through the back of the "2 gang outlet boxes" and the "2 gang outlet boxes" were secured to the wall.
    • Using the instructions on the box, I attached the wires (red, black, white, bare copper) to the NEMA 14-50 outlets and tightened the wire.
    • The NEMA 14-50 outlets were then secured to the "2 gang outlet boxes" and the wallplate was attached.
    • I also had some label plates manufactured to let any future homeowners know that they can't exceed 9.6kW of charging load at once between both outlets. That's what the breaker is for as well i guess..
    IMG_0012.JPG IMG_0013.JPG IMG_0014.JPG

    • After my install, I had to make an all-day appointment with the city inspector so that he could spend 5 minutes looking at the installation and justify the $250 permit fee..
    I hit my 10,000 character limit on this forum!!!

    Thanks!!!!. Please keep your hate mail to a minimum and let me know if there anything you would like to be expanded on :)
     
    • Informative x 3
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    • Helpful x 1
    • Love x 1
  2. Chris TX

    Chris TX Active Member

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    You're linking pictures that are being hosted by the Model 3 Owners Club, and you have to join it to view them.

    Try re-hosting on something like Imgur.
     
  3. Uricasha

    Uricasha Member

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    I"ll have to check out Imgur. I uploaded new ones.

    Thanks
     
  4. PV-EV

    PV-EV Member

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    Neutrals and grounds are normally kept separate except you are using a meter/main/loadcenter type of service panel and the main bond between the neutral and ground is done at that location. Therefore it is acceptable in your case. For many people this will not be the case. In general if your loadcenter is a separate box from your meter and main disconnect then the grounds and neutrals should be kept separate.
     
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  5. n2mb_racing

    n2mb_racing Member

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    I'm not sure if you are allowed to have that junction box and two 14-50 outlets on the same circuit.

    Why didn't you do two runs and two breakers? That's likely a safer way to go.
     
  6. n2mb_racing

    n2mb_racing Member

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    Might want to double check on this:

    "On 50A circuits, the rule is one breaker - one homerun - one outlet (NEC 210.23) The only exception is circuits which supply only cooking appliances (210.23C). If you want to use two devices on one circuit, unplug the one you're not using and plug in the one you are."
     
  7. Uricasha

    Uricasha Member

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    Table 314.16(A) of NEC
    • 3 (6-gauge) wires requires a minimum box size of 4" x 4".x 1.5" (I had 6" x 8" x 4")
    Table 210.24 of NEC
    • 50 amp branch circuit requires 6 gauge copper wire and 50 amp receptacles which is what I installed.
     
  8. Uricasha

    Uricasha Member

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    The City of Phoenix referenced NEC 2011. I don't see that exact language in NEC 210.23. 210.23.a.1 does say. The rating of one cord-and-plug connected utilization equipment not fastened in place shall not exceed 80 percent of the branch-circuit ampere rating. I created the label plates to go above and beyond the code. Also, the City of Phoenix inspector did not have any qualms with two outlets.
     
  9. PV-EV

    PV-EV Member

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    This is misleading even though correct. #6 conductors require 5 cu inches per conductor. Your error is in counting the number of conductors. Per NEC the number of conductors in your situation is 10 for a total required box size of 50 cubic inches. Each cable has three conductors for a total of nine and the grounds are counted as one. The box you selected is still large enough.
     
    • Informative x 2
  10. davewill

    davewill Member

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    Nice work! both the wiring and documenting your process.
     
  11. jcaspar

    jcaspar Member

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    I did something similar but instead ran 2g NM-B to a 100 amp subpanel in the garage, then two 50 amp breakers to two 14-50s. Added a 40 amp breaker for a charger for my daughter's Ford Focus. No spit bolts or electrical tape and can charge two cars at once.
     
  12. n2mb_racing

    n2mb_racing Member

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    I guess I'm just curious why you didn't do two runs and two separate circuits. I'd recommend that to others, if possible.

    I faced a maybe similar problem in my install. The load calculation we did would have been over 200 amps, if I installed two outlets. Figuring the upgrade to 400 amp service was going to be way too expensive, we went with one NEMA 14-50 for the model S and one NEMA 6-20 for the roadster. That solved the load calculation issue. The Roadster charges slower, but it gets less use anyway....
     
  13. jaguar36

    jaguar36 Active Member

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    I like how you actually paid the $250 permitting fee and had an inspector come and sign off on the install, and yet you still have folks on here playing back seat electrician.
     
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  14. TomatoOne

    TomatoOne Member

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    Thanks for the write up.

    Just want to remind everyone to pay attention to the local electrical code and other regulations. Some authorities recognize a dedicated EV charging outlet as an item of work, which might be cheaper to inspect (it's only $79 in Ontario). A switch within sight is also often required, so you can turn it off from inside the garage in emergency.
     
  15. jeffro01

    jeffro01 Active Member

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    Fair point but I've met plenty of inspectors who don't know the code very well so there's that... Flasher, where are you? :) I'm pretty sure the install violates NEC code because he branched the feeder circuit into two circuits but again, I'm just playing back seat electrician... :)

    Jeff
     
    • Like x 1
  16. ColdRauv

    ColdRauv Member

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    2014 NEC 210.17 states that the EVSE receptacles need to be on dedicated circuits, but Phoenix is on the 2011 NEC which has no such code language.
     
  17. ColdRauv

    ColdRauv Member

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    The 2017 NEC moves the requirements of 210.17 into 625.40 where it belongs.
     
  18. tga

    tga Supporting Member

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    Technically, 2Ga NM-B is only good to 95A (you have to use the 60C column)
     
  19. n2mb_racing

    n2mb_racing Member

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    All good points. I think the DIY is great and should be made sticky. I'm just wondering if the original poster could edit or add a note suggesting that putting two outlets on one circuit may not be allowed. Just add a recommendation that if you need two outlets, it might be a good idea to run two circuits.

    I'd say add that minor note to the original post then make it sticky. Someone in the future shouldn't have to read all our discussions to figure out the details. Everything should be summarized in the first post.
     
  20. SageBrush

    SageBrush Active Member

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    #20 SageBrush, Mar 1, 2017
    Last edited: Mar 1, 2017
    You must be kidding -- this is great!

    I'm curious, would an electrician have to pull a permit also ? $250 is really steep.

    I also appreciated the follow-up comments. Thanks all!
    My approach to DIY is to over-spec and over-build, and to err on the side of caution as a hedge against errors. It still works out to be much less expensive. There is more than a little good sense in having separate runs to each outlet, even if it is not strictly required by code.
     

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