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need help with running wire to a NEMA 14-50 outlet

Discussion in 'Model 3: Battery & Charging' started by tuoncan, Jul 16, 2018.

  1. tuoncan

    tuoncan Member

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    Hi,

    I'm thinking of running a NEMA 14-50 outlet to my electrical panel. I know the nema 14-50 has 4 wires. From the look of my electrical panel, i'm a bit confused as of where I should connect the neutral and ground wire to. Can I connect both wires to the same bus bar as where the green wire of my AC unit is connected to?

    See the picture below. Thank you for your help!
    20180715_135110.jpg

    Would using a 6-50 outlet a better alternative since that only needs 3 wires?

    Note. I know my main load can only take 100 amps. We currently have the AC unit breaker at 50 amps but since we don't use the AC at home and I will rarely come home to use the charger (i.e. I work far away). I plan to add an additional 50 amps breaker to the existing panel for now until I get a chance to upgrade my electrical panel in the future. I will be charging my car mainly at my 2nd house near work.
     
  2. mspohr

    mspohr Active Member

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    Assuming this is your main electric panel.
    Looks like a Zinsco panel which are notorious for electrical fires. Also, the panel looks very old and corroded. Not good.
    You really should replace the entire panel and all of the breakers.
    You only have 50 amp service? Is this your main panel or a sub-panel?
    There should be a separate ground bus (green and bare wires). Looks like some of the bare ground wires are connected to the neutral (white) bus. Not good. White (neutral) wires all go to the neutral bus.
    For the 14-50, you connect the green wire to the ground bus and the white (neutral) wire to the neutral bus. The two live wires (usually red and black) connect to the circuit breaker.
    However, as I said, you really should replace the entire panel and all of the breakers. This looks like a fire just waiting to happen... especially if you add a 14-50.
     
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  3. mongo

    mongo Well-Known Member

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  4. tuoncan

    tuoncan Member

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    #4 tuoncan, Jul 16, 2018
    Last edited: Jul 16, 2018
    This is the main panel with 100 amps for the whole house. I agree that this is pretty old. I will look into replacing it then. Should I go with the 200 amps new panel or should I need more than that?

    Thanks
     
  5. brkaus

    brkaus Active Member

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    You should probably start by calling 3 electricians for quotes.
     
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  6. mspohr

    mspohr Active Member

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    200 amp panel should be good. You don't need more unless you have a lot of air conditioning and more than one Tesla charging.
     
  7. P85_DA

    P85_DA Supporting Member

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    200a you need to get electric company involved ...and bigger cost ...you are a brave person trying to work with that panel !!! Get a nice Square D replacement ;)
     
  8. eprosenx

    eprosenx Active Member

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    Wow, I have not seen a panel like that before. Nice. I can not comment on how dangerous that panel is or is not (the internets do say there are safety concerns), the technologies have sure changed a lot over time, however, that one appears built into your house and so it may be painful to replace. I do believe there are aftermarket manufacturers of replacement breakers for these panels.

    To your questions though: If this is the main service panel then the neutral and ground busses should be solidly attached together and so they are functionally equivalent. I can't seem to verify this in the picture (partly because I don't know what the bonding setup looks like in this model of panel). If they are well connected together you can intermix ground and neutral connections on either bus freely.

    A 6-50 outlet may be a great option since you are right, you would not need to deal with landing a 6 AWG (or possibly 8 AWG) neutral wire under that ground bus (not sure if it is even large enough). Saves you on the extra wire too which is un-needed for a Tesla.

    That panel looks pretty cleanly installed and I see no obvious wire concerns.

    I would ask an electrician to evaluate this for you and for pricing on a new 200a panel (should be plenty given you are just fine on 100a right now and have very little in the way of circuits). I personally would want a new modern panel, but if cost prohibitive and an electrician did not have concerns then you may be able to get away with adding a new breaker to the existing panel. Perhaps a middle ground might involve replacing all the breakers in the panel (including the main) and really only just re-using the existing bus.
     
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  9. davewill

    davewill Member

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    You couldn't pay me to try putting a constant EV charging load on that panel. There's two separate upgrades being tossed around here. First is getting a new modern panel. That is just paying the electrician to do the work. The other is changing the feed to 200a, which involves the power company and may require new wires to be pulled from the transformer. You can do the first without doing the second.
     
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  10. Rocky_H

    Rocky_H Active Member

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    Yeah, good of you to make that clear. Taking out a 100A panel and replacing it with a 200A panel doesn't just magically give you 200A worth of capacity. Although I do hear that painting those racing stripes on your car is good for at least 20 extra horsepower.
     
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  11. RandyS

    RandyS Fan of Elon

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    Tuoncan,
    Not sure what your utility is in California, but you'll want to call and get connected with a Service Planner. They will work with you and your electrician/contractor on the job, and will ultimately issue you a work order or a service order that can be used to get a permit so that your contractor/electrician can proceed with the work. This work order will have all the instructions on it for your job.

    Is your home fed overhead or underground? Overhead can be easier when it comes to panel replacements or upgrades.

    If you are fed with an underground service, then the Planner will look at the system maps and see if you have conduit or perhaps direct-buried cable. If you have conduit, then it might be possible to pull larger wire that would support a larger electric panel. That would be nice. But if you have direct-buried cable, then new conduit and cable to the transformer will be needed. This may have to cross your driveway, sidewalk, etc. which would require trenching and perhaps concrete/asphalt work. That can be expensive.

    In addition, in San Diego, there is a new requirement that there be a minimum of 36" between your gas meter and your electric panel when you make these types of modifications. So that may require you to move your panel if you live in this area.

    Lots of things to consider...The first step is to call the utility and set up a call with the Planner....I hope that helps...
     
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  12. tuoncan

    tuoncan Member

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    Thank you all for the help and suggestions. I have requested my city for a "utility meter spot report" check. The permit to upgrade to a new electric panel is ~$155. I have a couple of quotes with ~$2000 at the lowest. The electric panel is outside on the back of my house. The electric is being feed in above to my roof from the pole nearby. After the spot check I guess I will find out if upgrading to 200A is doable or not. The worst case is getting stuck at 100A with a new panel.
     
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  13. eprosenx

    eprosenx Active Member

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    Yeah, I think what Dave was calling out was that you could install a 200 amp capable panel, but still just have it on a 100a service (might have to downsize the main breaker to 100a?). That way you would get away from the outdated panel, but might not have to upgrade the service at the same time if there was added cost to that (but still would be easy to upgrade later).

    But with that being said, I would not want less than a 200a service on my house and I would want a modern circuit breaker panel. Just seems prudent.
     
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  14. eprosenx

    eprosenx Active Member

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    Aerial service is typically stupid easy for the utility to upgrade. You just need a sufficient size conduit from the panel up to the weatherhead. I think generally you are responsible for the wire up to the weatherhead and from there the utility will splice on their own wires (typically smaller gauge since they are cooled better hanging in free air).
     
  15. 3inthree

    3inthree Supporting Member

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    My wife is a Realtor, and she has handled several transactions where the house had a Zinsco panel. Most of the major insurance carriers here in Florida won't insure a house with a Zinsco panel. As a result, several sellers have had to replace the panel. In most cases, a 100A panel was about $2,000 installed -- so the estimate you got was in the ballpark.

    Good luck!
     
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  16. Rocky_H

    Rocky_H Active Member

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    Even if you don't get a larger main service, I think that would still put you in a pretty good situation. If your house does fine with 100A service now, that's probably still fine, with some space to add a little bit. My house, built in 1996, only has a 125A main service, and it's fine. Part of this that I would suggest is not to get hung up on thinking you NEED a 50A circuit for overnight charging anyway.

    I usually suggest people back into this calculation from how much they drive into how many miles they would need to be able to refill overnight. Let's look at possibly a smaller level of circuit. If it were a 30A circuit, you can get 22 miles per hour of recharging on a Model 3. If you get to charge overnight while you sleep for 8 hours, that is 176 miles overnight. I would think the vast majority of days, you probably won't need that much. Maybe if you could only get a 20A circuit, that's still 15 miles per hour. That's 120 miles every night. That should still be pretty solid for most of the time. And if there's some rare occasion a few times a year, where you need more than that faster, you're in California--there's a Supercharger somewhere nearby that you can use to cover that unusual case.

    Within the load calculation, there's a provision called "non-concurrent use", where you can have two different loads that are going to be used at opposite times of day, so you only need to pick the larger of the two to add to the total. So your oven, clothes dryer, or air conditioner are generally daytime use, but the car charging circuit will be mostly overnight, so it should be able to offset with one of those others to let you fit in a decent circuit in a 100A service.
     
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  17. Glamisduner

    Glamisduner Active Member

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    If your going to replace the panel you may as well upgrade to a 200 amp since your getting an EV, whatever the extra cost is IMO.

    Unless you don't care if you have to upgrade again in the near future?
    I mean if your going to upgrade I would do it right, and now would be your best time to do it...

    What if you want to add solar in the future? I mean your in SD and power is expensive, your going to want solar and will likely need a bigger panel at that time.

    I would imagine the ground would go where the green wire is and the neutral on the side with the other neutrals. From what I have read they are all connected to the same buss, but this helps keep them organized.
     
  18. mspohr

    mspohr Active Member

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    The ground bus and neutral bus should be kept separate until the service entrance where there should be a good earth ground.
    If they are connected in other places, you risk creating "ground loops" with potential untoward effects.
     
  19. eprosenx

    eprosenx Active Member

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    Normally I would think about this the other way around (I think you are correct in your thinking, but I would describe it differently). The ground bus and neutral bus must always be kept separate downstream of the service entrance, but they are always tied together at the service entrance. It is pretty clear in this case that we are looking at the service entrance from the fact that it is outside and it is described as the main panel. (so they can be used interchangeably here, though not a horrible idea to keep them separate in case this panel ever became a sub-panel for some reason and needed to be separated)

    Just to provide some terminology clarity here: "Ground Loops" are generally defined as unwanted "noise" on grounding conductors normally caused through induction from other electrical wires. The condition you are warning about here is very valid, but I don't think "ground loop" is the right terminology. "Unintentional Ground / Neutral Bonding" is how I would put it. The danger is that you could end up with ground paths (like metal conduit) having current flowing over them between a subpanel and the main panel.
     
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  20. mspohr

    mspohr Active Member

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    I'm confused that this is the main panel.
    I don't see a 100 amp breaker. I don't see any obvious feed to this panel.
    There is a 50 amp breaker on the right which could be the service feed to the panel but then it's only 50 amp service (and there's no neutral wire with this feed.)
    A large earth ground is connected to all of the neutrals plus a few ground wires. There's a single green ground wire on the left (which seems to come in with the wires to the 50 amp feed) but I'm not sure this bus is connected to the neutral bus.
     

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