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Need advice about installation NEMA 14-50

Discussion in 'Model 3: Battery & Charging' started by BestHand, Jul 19, 2018.

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  1. BestHand

    BestHand Member

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    While I am waiting for Tesla email (sep18-Nov18 delivery) I am thinking about installation of NEMA 14-50 in my garage.
    Generally it should not be complicated as I am an engineer electrician myself, but in USA I work as a programmer and not familiar with codes. I see some complications in my case:
    1. Electrical box has only one pole free left. I am thinking of using wire nut to join wires of two circuits and piece of additional wire to connect the to one pole and make one breaker free. Then I could remove it and I will have two poles available.

    2. Electrical box is installed in between two vertical wooden stands, so I guess I can use only bottoms holes for the cable (all top holes are busy).

    3. There is some kind of shelf bellow the box, you can see on a picture (where also you can see the hose), and it looks like it is made of plywood. I do not know if I may install NEMA 14-50 receptacle on that surface.

    The electrical box has 100A main beaker.
    A/C uses 40 two poles breaker.

    I will use my car not often, as I do not use it to my work commute. Actually for me even 120V charge will be enough, but I still like to have NEMA 14-50 just in case.

    What would you do in my case?
     

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  2. P85_DA

    P85_DA Supporting Member

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    Replace one of your breakers with double pole breaker (combine ) and free slot ..you can mount the 14-50 on surface
     
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  3. BestHand

    BestHand Member

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    Do you mean single-pole Tandem Circuit Breaker? I like that idea, as every circuit still will be on its own breaker.
     
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  4. P85_DA

    P85_DA Supporting Member

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    #4 P85_DA, Jul 19, 2018
    Last edited: Jul 19, 2018
    726570D1-8DC6-4A43-98CD-CC99C41188D6.jpeg Yes
     
  5. Rocky_H

    Rocky_H Active Member

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    That's what I was hoping to do on mine, because I had this same issue, with only one single slot free, but mine was a Square D Homeline panel, that has non-split bus bars, and those WON'T take any of the tandem or quad breakers that will let you combine spaces. So there wasn't any way to use the tandem breakers. And guess what?! My panel looks exactly like his, so he may have the very same problem! So check that ahead of time if those kinds of breakers can even work in your panel.
     
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  6. P85_DA

    P85_DA Supporting Member

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    95F5C69D-90FB-4105-89F4-DC8F595DECF6.jpeg I have square d home line panel as well and use this...also his looks like a Murray /Siemens style
     
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  7. Rocky_H

    Rocky_H Active Member

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    Yes, but Square D makes a few styles of panels and some have the split bus bars and some have the non-split bus bars. I actually bought quad and tandem breakers to try to get this to work, and they are made to physically not fit in there if you have the non-split bus bars. I had to return those breakers since they couldn't work and had to do something else. (give up another circuit)
     
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  8. P85_DA

    P85_DA Supporting Member

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    302798A3-9AAD-4FE4-96FE-A74C28C062DF.jpeg Square d panel
     
  9. P85_DA

    P85_DA Supporting Member

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    Ahh ok I would have assumed they are all same lol
     
  10. BestHand

    BestHand Member

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  11. eprosenx

    eprosenx Active Member

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    I will second what others said about using the "double breaker in one" breakers. I bet your panel will accept them. Please post a good quality picture of the writing on the door of your panel (hopefully has info on which breaker types are allowed, model numbers, etc...). Then also a close up of the breakers so we can read the ampacities (make sure we have a pic of the list of circuits also). Additionally, please take the cover off if you are comfortable with that and take a picture that shows all the wiring.

    Technically you need to run a load calculation of all the devices in your house to make sure that you are not exceeding the capacity of the 100a feed, though since you have an understanding of this stuff if you had to you could aways swap down to a 14-30 receptacle or manually set charge current lower if it became an issue.

    Yes, you will probably want to run the new power out the bottom - though that shelf is odd and greatly complicates things. That is what I did on my panel. I used EMT for my Wall Connector, but I just used Flex for my NEMA 14-50.

    I had to expand a knockout in the bottom of my panel from a 1/2 in size to a 3/4in size using a punch tool. It was not hard.

    FYI- There was some code I think previously in NEC that said you could not have more than 42 poles in a breaker panel, though they may have dropped that (though manufacturers have not updated equipment yet to reflect that I don't think). So that I think drove the "can't have tandem breakers" interlock requirement. So like my panel had 20 breaker spots, ALL of them were allowed to be tandem. Others that had 40 spots allowed NONE to be tandem. Ones with 30 spots often have 10 spots that can be tandem (notched), and 20 that can't be tandem. So you have to look at the spec on the door generally which tells you this information.

    MyInstall.jpg
    BreakerPanel.jpg
    InsidePanel.jpg
     
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  12. P85_DA

    P85_DA Supporting Member

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    @eprosenx how to u like that Sense monitor? Was thinking of getting one but still somewhat pricey
     
  13. Rocky_H

    Rocky_H Active Member

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    I'm trying to do some searching on it to find detail, but the terms are killing me in Google, because there is a different thing that uses almost the same words. There is a lot of discussion of single bus or split bus panels. That has to do with whether you have one single main breaker that disconnects at the top because it's two continuous bars that run all the way down. And the split bus is where it may have the bottom half of the panel as physically separate from the upper half, so you have multiple disconnects. That is usually older panels, and that's not what I'm talking about.

    The thing I'm talking about is where you are snapping the breaker down onto the bus bar, does it look like metal tabs that stick up and the breaker completely covers over them? Those kind can take those tandem and quad kind of breakers. My panel does NOT have that kind of bus bars. Mine is like you are holding up a ruler on edge. It's one extended bar that goes across, so the breaker goes down onto it to squeeze that ruler, but the ruler still sticks out the slot in the end, so it needs a very deep slot, which those specialty breakers are not made with.

    Maybe I'm forgetting the right term, but I thought it was something like "continuous bus bar" versus "split bus bar", but I'm having a hard time finding references or pictures of it.
     
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  14. BestHand

    BestHand Member

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    here it is:
     

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  15. P85_DA

    P85_DA Supporting Member

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    Ok you have 100a service u can use Murray/Siemens breakers like my very first pic at top ...I believe even the square D QO(quick out) breaker will fit...those 15s at bottom look like good candidates to free space
     
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  16. eprosenx

    eprosenx Active Member

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    Away from my laptop (more on this later) but PLEASE do not try to use square d breakers in this panel. Mixing different manufacturers breakers can be dangerous unless they are rated for that use. Lots of breakers are cross rated (since they have been sold under different brands over the years but are the same design), but I don’t think square d falls in that category with Murray.

    I can research more later.

    It looks like all of your breaker positions are rated for tandem breakers. Please send a slightly further zoomed out picture of the panel so we can see all the wires. I need to make sure you don’t have any shared neutrals (if so you have to be strategic in how you tandem them).
     
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  17. BestHand

    BestHand Member

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    So, that is what I thought to do. Last two 15A breakers out, one tandem breaker and 50A two poles breaker in. Will cut a hole for the box on a vertical surface of a shelf bellow (still do not know if it is a plywood or sheetrock, probably does not matter). Generally nothing really complicated, just want to make it reliable. That hose under a bit on a way though...
    Also the box on a right wall, close to the gate, so charging cable will lie on a car...
     
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  18. BestHand

    BestHand Member

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    As I checked, the wires do not have any shared neutrals.
     
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  19. eprosenx

    eprosenx Active Member

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    Oh good. Though are you positive? I am very suspicious since you have a bunch of red wires in your panel. Normally I only see red wires when they are in a sheath with another black wire (shared neutral).
     

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