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  1. #1
    Jim Otten's Avatar
    Jim Otten Guest

    Default How to locate grounding electrode system

    I need to locate the grounding electrode system for my home. The service panel and GEC were put in place in 1990 when major renovations where done to the vintage 1906 house. In 1990, the basement was excavated and retaining walls poured.

    I do not see any wire coming from the service panel or house to track it to the GEC (the wires are inside the wall, and I do not know where the ground wire exits to the exterior of the house or where it bonds to the grounding system) . I also do not know what kind of grounding electrode system was required in 1990-91 (work was done with permits, so I am confident it met code requirements, I just don't know what those requirements were).

    Do I look near the service panel, near the water main into the house, . . . ?? Before I start digging, I'd like to have the best chance of finding it, and also to know what I am looking for.

    Any help and suggestions will be appreciated.

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  2. #2
    James Duffin's Avatar
    James Duffin Guest

    Default Re: How to locate grounding electrode system

    Have you looked at the meter base for the GEC? It may be just as easy to drive a new ground rod and run a new GEC.


  3. #3
    Jim Otten's Avatar
    Jim Otten Guest

    Default Re: How to locate grounding electrode system

    Thanks James. I have not looked anywhere yet -- I'll have to dig -- but if the service base is the most likely place, then that is where I will start. I wanted to find out what the practice/code was in 1991 (California) to try to narrow my efforts to the most likely successful place to dig. Is it likely that my house will have a rod driven into the ground (could grounding system be only made up of wire bonded to water pipe??)


  4. #4
    Join Date
    Mar 2007
    Location
    Knoxville, TN
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    2,446

    Default Re: How to locate grounding electrode system

    Since you are not really sure what you are looking for, I suggest you call an electrician or a home inspector in your area and have them look.


  5. #5
    James Duffin's Avatar
    James Duffin Guest

    Default Re: How to locate grounding electrode system

    Quote Originally Posted by Jim Otten View Post
    Thanks James. I have not looked anywhere yet -- I'll have to dig -- but if the service base is the most likely place, then that is where I will start. I wanted to find out what the practice/code was in 1991 (California) to try to narrow my efforts to the most likely successful place to dig. Is it likely that my house will have a rod driven into the ground (could grounding system be only made up of wire bonded to water pipe??)
    The water pipe can not be the only GE. See the code comment below.

    (2) Supplemental Electrode Required.
    A metal underground
    water pipe shall be supplemented by an additional
    electrode of a type specified in 250.52(A)(2) through
    (A)(8). Where the supplemental electrode is a rod, pipe, or
    plate type, it shall comply with 250.56. The supplemental
    electrode shall be permitted to be bonded to the grounding
    electrode conductor, the grounded service-entrance conductor,
    the nonflexible grounded service raceway, or any
    grounded service enclosure.


  6. #6
    Join Date
    Mar 2007
    Location
    Plano, Texas
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    4,170

    Default Re: How to locate grounding electrode system

    First off, don't endanger yourself if you are not qualified to work on electrical... and yes, the GEC is part of the electrical system and you can die just as dead from doing the wrong thing with it!
    That said, typically where I am located there will be a note at the service equipment as to where the bonding clamp is located for the water pipe, then there will also be a clue as to which direction the GE is depending on the direction of the GEC.
    Next, why do you need to locate the GEC? It might make a difference in the answers. Is the house a slab, crawl space, or basement?
    A picture of the meter, panel and a perspective shot or two would help.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  7. #7
    Jim Otten's Avatar
    Jim Otten Guest

    Default Re: How to locate grounding electrode system

    To answer some questions and give addtional info:
    I need to find the GEC/ground rods because:
    (a) The electric meter is no longer seated properly on the service panel (unclear what the cause of the improper seating is, but it has been that way for quite awhile -- house settling, never properly seated in the first place ???) - There has been no work to the electrical system for 20 years.
    (b) The electric company wants certain things verified (e.g. grounding electrodes) before they will reseat or install a new meter.

    If I can not find the grounding electrodes, then I will have an electrician install new rods (two 8-ft rods would be called for under current code). If I can find the existing GEC and show where it is bonded to grounding rods and/or water pipe to the Utilities Company's satisfaction, then I will not need an electrician to re-work the existing system. The ideal situation for me would be to find everything in order so that no additional work is required other than having the utilities company come to reset (or install a new) meter.

    I am not an electrician, but I have significant understanding and experience with electrical systems. I am doing the initial ground work to find out how much, if any, I will need from a certified electrician before the utilities company will fix the meter.

    I carefully dug just a bit today in the immediate vicinity of the service box, but did not find anything. I'd love to get information on where you guys think the most likely bonding location would be, how deep it might be, etc. And can anyone confirm that in 1991 a grounding rod was required in addition to bonding to water pipe (I realize current code is not met with bonding to water pipe alone). The reason I ask, is that if it was only bonded to water pipe, then I'll add grounding rods anyway (even if I could be grandfathered -- remember, I'm not having any "work" done, just reseating the meter). But if ground rod(s) were definitely required in 1991, then I am confident they are there (as it would be up to code at that time) so I want to find them.

    To address your question of what the situation is: In 1991, the basement was excavated, and retaining walls were poured. A 200Amp service was put in, as the basement was wired at that time. Is the GEC ever laid partially in the concrete of the retaining walls?

    I hope this helps -- here is a link to a youtube video which shows the layout.
    YouTube - IMG 0421

    Thanks all.


  8. #8
    James Duffin's Avatar
    James Duffin Guest

    Default Re: How to locate grounding electrode system

    I would just drive a new ground rod and run a #6 bare copper wire to the small lug beside the neutral lug in the meter base and be done with it. Be sure and put the underground ground clamp on the ground rod before you drive it or you will not be able to get the clamp on due to the top of the rod being mushroomed.


  9. #9
    Join Date
    Feb 2009
    Location
    Southern Vancouver Island
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    4,546

    Default Re: How to locate grounding electrode system

    To answer your question, yes you could have a Ufer ground, grounding conductor
    embedded in the 1990 concrete. The bare copper could then be completely enclosed behind the wall sheathing, but the upper end will be visible when they pull the meter.

    A third possibility is a flat plate buried 2 feet underground. The grounding wire would be normally visible outside before going underground, so that seems unlikely.

    Much as you would like to assume the work was properly done to code, we see plenty of cases where mistakes have been overlooked. Sometimes the authorities are simply too busy with the big projects to get out to the small reno jobs. Approval is sometimes granted without an inspection, at least that's the case here.

    Last edited by John Kogel; 05-08-2011 at 10:20 PM.
    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

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