TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Installing Separate Meter for my Tesla - Please Inspect before inspection fails

Discussion in 'Model S: Battery & Charging' started by ohaq, Oct 30, 2015.

  1. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan
    I live in Michigan, Ypsilanti. We are int he process of installing the second meter and nema 14-50 plug our self. Well the purpose of doing this ourselves (me and my cousin) is that he likes to do these kind of projects and he insisted that we give it a try. Any ways I went to the township for a permit and got a permit.

    I called DTE and they emailed me instructions, I copied some instruction at the bottom for wire specification where we are a little confused. Questions at the bottom.

    Below are pictures with some text explaining what i have done so far.

    outside 1.jpg
    outside: In the above image you see a separate meter 125amp installed with seu 2-2-2 connected to the top and SER 2-2-2-4 connected to the bottom. I went to lowes first and bought this cable they did not have 2-2-2. I asked if it was okay for me to use this the lowes associate said yes just dont use one of the wires, so we clipped the ground. white,red and black are connected. we ran out of cable so went to homedepot to get the 2-2-2 which will be connected to the main meter

    The main meter is locked so no connection is made to the main meter. The document provided by DTE said to connect to the load side and leave enough cable so that DTE can then move it to main line.

    outside 2.jpg
    outside

    inside 1.jpg
    inside garage: The cable on top is the old cable coming directly from the main panel, so lets ignore that.

    inside 2.jpg
    The bottom cable is coming from ev meter to 100amp panel. The reason for 100 amp is so that i can add another breaker when i get model 3. The cable coming from meter to panel is less than 10ft.

    Questions
    1. What did i do wrong above that will fail inspection? Now that we have done so much i would like to do all the fixes as well instead of getting an electrician to look it over and fix and do the remaining tasks.
    2. Do i need to ground the ev electrical panel? I did not right now as i thought that the panel is connected to ev meter which will connected to main meter which has a ground connected to it. I i do need to ground it can i just take the ground from the main panel?
    3. For inspection do i need to connect the to meters together and install a jumper in ev meter so that the inspector can test the connection? or will the inspector have jumper bypass with him?
    4. In Michigan home owners are allowed to pull the meter out so i have already requested DTE to remove the lock.

     
  2. brucet999

    brucet999 Active Member

    Joined:
    Mar 12, 2015
    Messages:
    1,314
    Location:
    Huntington Beach, CA
    You must ground the EV breaker panel just the same as your house main electrical panel. Since it is metered separately, it must remain as a stand-alone system not connected in any way to your house panel. Check local codes for grounding service panels. You probably will have to drive a grounding rod into the earth and perhaps bond to any gas or water pipes.
     
  3. wk057

    wk057 Senior Tinkerer

    Joined:
    Feb 23, 2014
    Messages:
    4,722
    Location:
    Hickory, NC, USA
    I'll leave a better response in the hands of FlasherZ, who has more knowledge of this particular area than I. My knowledge of service entrance related NEC items is a little fuzzy these days since it's not something I deal with.

    I assume you're trying to add a second utility meter due to needing larger service? Or are you just trying to monitor EV power usage?

    First, I see no grounding in your new panel. I can't think of a situation where the neutral conductor is allowed to also be the ground wire when feeding a panel. If it a service panel, the ground and neutral are to be bonded at the panel, thus requiring both present. If it is a sub panel fed from a service panel or sub panel the ground and neutral are to be separate and not bonded, thus requiring both present.

    Your existing utility meter pan may not support additional taps in this fashion depending on the service or load side in the original meter pan. The original meter pan may need to be replaced to make this work to code, and the incoming conductors may need to be replaced on the utility side given the added capacity. If you're existing panel is at load calc capacity it's more than likely your service conductors from the utility will need to be upgraded.

    Overall, and no offense intended, based on the questions it would seem that you should probably grab a copy of the NEC for whatever revision is in effect in your jurisdiction and study the relevant a bits before continuing and potentially making costly mistakes. Barring that, a professional electrician could get this done in no time at all and likely not even all that expensive. There are a lot of rules that apply and it's generally not as simple as just throwing a few wires together and presto. Grounding rules, specifically, can get pretty complicated.
     
  4. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan
    Thanks i look into the grounding service panel. My parents also have a separate meter but in their case the electrician connected the separate meter to HOME LINE Load Center HOM24L70RB Load Center , 70A with a 50 amp breaker. I opened that up and saw that it did not have a separate ground like the main panel and based on that setup i thought i might not need one as well for my 100 amp main breaker.

    Thanks for the input.

    - - - Updated - - -


    The new meter is required for the DTE PEV rate so that DTE can monitor the EV charging and bill me separately for the EV charging.

    The main breaker is 150amp and i was charging using that i.e the old wire you see in the picture (not connected to the panel), now to get the new rate the new panel is added.

    It wasn't expensive getting an electrician to do it. It was $600 but that was for a Separate meter and 50amp connection. Later my cousin convinced me that we can do it and then the project became bigger from a 50amp to 100amp panel. I guess I can hire a electrician now and have him complete the job.

    Adding ground rods seems a lot of work, tapping into the existing ground seemed simpler.

    I am not sure what was special about the connection at my parents house done by the electrician. He connected the separate meter to HOME LINE Load Center HOM24L70RB Load Center , 70A with a 50 amp breaker, no special ground wire ws going into the load center.
     
  5. brucet999

    brucet999 Active Member

    Joined:
    Mar 12, 2015
    Messages:
    1,314
    Location:
    Huntington Beach, CA
    I'm quite surprised that you are apparently allowed to run sheathed cable like that on the exterior of your house with no protection from mechanical damage.
     
  6. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    #6 FlasherZ, Oct 31, 2015
    Last edited: Oct 31, 2015
    First, quick terminology note - in your photo, that's not the "main panel" or "EV panel" that hold the meters - that's your "primary meter pan" or "EV meter pan". Panels are the breaker boxes.

    A few thoughts from a quick glance, although it may not be everything. First, the disclaimers: sometimes local codes differ, so no guarantees this helps you or is complete. I am not a state-licensed electrician in Michigan (nor in my local states, as Illinois and Missouri do not require licenses, leaving it to county & municipalities to establish their standards), and have no knowledge of specific Michigan codes. A local electrician will help you understand any local standards that may need to be followed or may differ from the below.

    1. Clipping the ground as close as you did may cause heartburn. Since the sharp edges of clipped conductors can compromise the insulation when other conductors rub against them, the proper way to handle it would have been to leave more exposed, then cap and/or secure the conductors. Your inspector might have heartburn at how close you clipped those.

    2. Non-conductive conduit bushings are required to cover the inside ends of the fittings in the meter panel and EV service panel where the cables enter the box.

    3. As noted by brucet999, in my area you're not permitted to run service-entrance cables where subject to damage. 230.50(B)(1) says it must be encased in an approved conduit. You may have local codes that permit it, but I haven't seen any. I would run conduit from meter to meter

    4. NEC 230.70(A)(1) requires that service panels be placed as close as possible to the meter, either outside or at the point at which the conductors enter the building, because the service-entrance cables are not over-current protected (except by transformer fuse). If it is further than 5 feet from the point at which your wires enter the building to the EV breaker panel, a disconnect may be required at the point of entrance into the building (either inside/outside), or you need to move that panel. The location is also important, because if your EV service breaker panel is not in the same area(generally reachable from the same spot) as your main home's service panel, NEC 230.72 requires you to place a primary service disconnect near the main breaker panel, and you'd have to run a 4-wire connection (including ground) from that primary service disconnect to the subpanel that you have -- all service disconnects for a building need to be grouped together. Finally, in that case, #2 cable will not be good for 100A because NEC limits #2 aluminum to 90 amps, you'll need to bump up the wire size between the disconnect and the EV charging panel.

    5. The grounding requirements are not met. (EDIT: See below for more details in addition here. This may not be an issue where you are.) The new panel in your garage is considered a service disconnect panel, and is required to be grounded in the same way that your existing home panel is - typically, a continuous #8 (for 100A) (minimum) copper conductor connected from the panel's neutral/ground bus to two 8' (minimum) rods driven 6' (minimum) apart into the earth. You can use the same ground rods as your primary panel, but must run a separate conductor and separate clamps from the new panel. If you require a service disconnect (the point above), you ground the service disconnect, then run a 4-wire connection to the EV breaker panel, separating grounds and neutrals - this panel will not be considered a service panel but rather a subpanel.

    In general, for inspection purposes you will not have to have the system live, so no jumpers will be needed. Keep in mind that if your jurisdiction requires it, you will first need to clear the inspection through your appropriate inspection office, then the power company generally does its own inspection and connects it.

    While your power company allows you to pull the meter, it probably doesn't allow you to reconnect it without the power company being present. Typically, how this works is that you schedule the power company to pull the meter (or do it yourself), you schedule the inspection at the same time, and schedule the power company to come back and turn on power later that day after the inspection is tagged complete. The risk you run is that if you fail the inspection and get red-tagged, the power company won't turn you back on unless the inspection clears. In this case, you can probably simply unbolt the new conductor in the primary meter pan and have them reconnect for you. That way you can correct errors if any.

    (EDIT: #5 was modified based on more clarification and I address more below.)
     
  7. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan

    Thank you very much for all the details. I am having a OMG moment. I will run through all these with my cousin and if he gives up then we will have to have an electrician come and have him do the rest. HE might swear on our messup.

    Thanks again great information, point 1 makes me laugh each time I read it. Inspector heartburn. Looks like this project will be prolonged to next week.

    - - - Updated - - -

    Thanks All, I cant believe that all of you have been so nice in your response. Looking at what i have done, I am speechless.
     
  8. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    No problem. Some of this stuff is complex with all the rules over the past 20 years or so. Since the early 1990's, standards have changed very significantly, and it's tough even for those who regularly do work to tick-and-tie each point. I keep the NEC on the desktop of every computer I have (and a portable version in my phone).

    I would recommend reaching out to your inspector, even before you schedule the official inspection and ask any questions you might have, if you're unclear on anything. Most of them want to help, although occasionally in very busy locales they will refer you to a contractor/electrician.

    Some parts of the code are subject to interpretation, too - the only opinion that matters is your inspector as the Authority Having Jurisdiction (AHJ).
     
  9. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    #9 FlasherZ, Oct 31, 2015
    Last edited: Oct 31, 2015
    Ok, I read something that reminded me I need to confuse you even more about grounding. :)

    It is permitted in some areas to run the grounding from the meter pan, and that's a power company standard (this is actually very common); in this case, you will not need to run that ground conductor from your EV service panel to grounding rods. You need to look to see how your system is grounded: in your main breaker panel, is there a large-diameter copper wire that runs externally to grounding conductors? If so, you'll need to do the same for the EV panel. When you open the primary meter pan, you might find your ground connected in there - in which case you don't have to worry about grounding, because it's done through the neutral.

    It's a very confusing topic, I know, but I tried to simplify it as much as possible.
     
  10. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan
    Yes the main breaker/panel has 2 ground wires one coming from outside, I assume coming from the ground rods and the other going towards the water pipes inside the basement. At my parents house there was no lock so i looked at the main meter pan and saw that the ground was connected to the neutral in the pan. I guess this is why at my parents he did not run separate ground.

    Again thanks for all your help. I got the no of my inspector and will wait for DTE to unlock the pan to see whats going on in there.
     
  11. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    No problem. Good luck!

    (And that locking mechanism is one I don't see all that much out in this area - they use simple meter seals that you can cut yourself with their permission.)
     
  12. brucet999

    brucet999 Active Member

    Joined:
    Mar 12, 2015
    Messages:
    1,314
    Location:
    Huntington Beach, CA
    Can OP run solid copper grounding wire from his EV panel to the same grounding rod and water pipes as the main panel, or does he need separate grounding rod?
     
  13. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    You can use the same rods but need separate wire and clamps. You don't have to ground to the water pipe unless it's considered one of the two electrodes - the water system bonding is only needed from the main panel.
     
  14. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan
    Great Information here. Thanks all.

    DTE removed the lock, I looked and the ground is not connected in main meter pan :mad:. I was hoping that it would be similar to my parents house but its not.

    At my parents the connection is similar to this image below
    meterground.PNG

    It seems that i will have to run the ground wire to the rod as i dont have a ground coming in to the main meter pan.

    My ev panel is less than 5 feet from the meter but i am using around 8 feet of cable to connect between the ev meter pan and panel. I am going to take a chance and see if the inspector points that out, if he does then i'll fix it.
     
  15. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    I don't think you'll have an issue. There are two reasons why service panels need to be as close as possible to the cable entrance: 1) service entrance conductors are unprotected, except for a transformer fuse that really doesn't provide protection; and 2) the service disconnects (main breakers) to disconnect all power for the building must number 6 or less and must all be grouped together in the same rough location.

    - - - Updated - - -

    While you're in the main meter pan, is there an unused set of lugs on the load side (typically bottom) to which you can attach the wires temporarily? If not, you may need to add some, if the meter pan allows you to do so. Eventually, it sounds like the power company will move them to the top (when they can disconnect the transformer), but you'll need room on the load side for now.
     
  16. kennybobby

    kennybobby Member

    Joined:
    Sep 14, 2014
    Messages:
    479
    Location:
    Heart o' Dixie
    i wondered about that from your OP photos--didn't see any ground rods and thought they may be using the steel conduit as the ground path.

    i figured that you would regret the Lowes advice to cut the ground wire since you likely need to ground the ev service panel back to the ev meter pan.
     
  17. JeffS

    JeffS Member

    Joined:
    Oct 7, 2015
    Messages:
    239
    Location:
    Wisconsin
    Just a thought from some guy that you have no reason to believe or consider. Electric cars pull big power. Mostly night when nothing else is on...but still.

    Homes and apartments are insured against loss. Sometimes electricity makes things start on fire. Insurance covers the damage when this happens.
    Unless the homeowner wired something. Then they get a whole big line of other "experts" and "inspectors" over to see if there is any reason they shouldn't cover the loss. Their goal - don't pay. Simple business principle in the insurance world.

    There are obvious signs that wiring was done by a homeowner. There are things professionals do when they wire that make it obvious it was done by a professional.

    I ran a separate meter for my electric car charging equipment. Meter is on a shed. Circuits are pulled underground to the garage. Two 20A charging stations and one 50A for my Tesla all in the garage from the dedicated panel in my shed.

    I did the grunt work. But had a licensed electrician under a proper permit, pull all the wire and make the circuits hot. That's proper in my book.
    Even if the car's charging circuit doesn't create a problem that starts a fire - the existence of a home-owner-installed big drawing circuit gives insurance companies a reason to send in their "experts". To me, that's just not worth the risk.

    Again, just some guy and his opinion. For what its worth.
     
  18. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan
    Thanks for the replies. All suggestions are appreciated.

    Here are 2 ideas that are crossing my mind. I will go with the first 1 unless someone says that both are equally good and then i would just go with the easy one.


    1. Connect ground from ev breaker panel to ground rod
    2. Connect ground from ev meter pan to ground rod. This way all work can be just on the outside

    The green box is where the ground would go if i connected to the ev meter pan. I guess to be consistent i should copy what was already done i.e. bring the cable from the main breaker panel to rod.
    ev pan.PNG

    here is the current ground going to the main break panel, in the green box, bare wire.
    GROUND.png
     
  19. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    Your power company gets to determine that one. The NEC permits you to connect the GEC's anywhere between the load side of the meter and the service disconnect panel, but the power company sets the standards for the meters and whether they get grounded. My guess is that the standard in your area is to ground it from the main panel, meaning you should run a ground wire to your EV panel.

    Because your supply conductors are #2, you only need a #8 ground wire to your ground rods. It must be a continuous length of wire, though, no joining it together anywhere.

    (If your power company allowed, the *best* option is actually to connect your GEC's to the primary meter pan and disconnect it everywhere else, then you don't have to worry about grounding the EV panel...)
     
  20. ohaq

    ohaq Model S #P9,326

    Joined:
    Apr 20, 2012
    Messages:
    228
    Location:
    Michigan
    Thanks again, I think both ways are okay in our area as my parents house is also near by in the same city and we have the same power company (DTE) and in their case the ground is connected to the main meter pan. Parents house was built in 2005 and mine in 2002. Now I am thinking of pulling the ground wire connected to the main breaker panel and just connected it to the main meter so that i dont have to dig to get to the rod.

    Thanks for pointing that it should be continuous length.

    I have trying to get hold of the inspector, he must be busy, as he hasn't returned my call.
     

Share This Page