Results 1 to 12 of 12
  1. #1
    Join Date
    Dec 2008
    Location
    Erwin, TN
    Posts
    310

    Default Grounding Electrode ?

    Would this be considered a proper grounding electrode ? I thought the water supply line had to be metal ?

    Similar Threads:
    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    OREP Insurance

  2. #2
    Join Date
    Mar 2007
    Location
    Santa Rosa, CA
    Posts
    3,035

    Default Re: Grounding Electrode ?

    Quote Originally Posted by Sam Morris View Post
    Would this be considered a proper grounding electrode ? I thought the water supply line had to be metal ?
    Sam,

    You are correct. That would not function as a grounding electrode.

    Are you certain that is the intent? Could it be bonding of the metal household water supply piping?

    Is it possible that there is some other type of grounding electrode? Such as a ground rod or Ufer? How old is the home. Around here, the vast majority of homes built since around 1970 have used Ufer (concrete-encased electrode) rather than a ground rod or water supply.

    If this is an older home or if your area does not use Ufers, then the main water supply pipe may have been replaced. (An "older" home in my area would be 1960s or before).

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  3. #3
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    682

    Default Re: Grounding Electrode ?

    For a very long time it has been a rule that if a water line is used as the grounding electrode there has to be a supplementary grounding electrode, usually a ground rod. Most likely this will be wired to to the main panel. If not present it needs to be added. In recent codes it is required that there are 2 rods 6 or more feet apart.

    If the metallic water supply pipe doesn't extend at least at least 10 feet beyond the foundation it can't be used as a grounding electrode. There doesn't need to be a water pipe used as a grounding electrode, it just has to be used as one if present.

    The metallic pipe shown in the pictures definitely needs to be bonded to the system ground at the panel, and that would be the function of the wire you see (assuming it's hooked up on the other end.)

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  4. #4
    Join Date
    Mar 2007
    Location
    Santa Rosa, CA
    Posts
    3,035

    Default Re: Grounding Electrode ?

    Quote Originally Posted by Bill Kriegh View Post
    If the metallic water supply pipe doesn't extend at least at least 10 feet beyond the foundation it can't be used as a grounding electrode. There doesn't need to be a water pipe used as a grounding electrode, it just has to be used as one if present.
    Bill,

    Are you saying that a metallic water pipe that is buried at least 10' MUST be used as a grounding electrode? I was not aware of that.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  5. #5
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    682

    Default Re: Grounding Electrode ?

    Gunnar, Art 250.50 states that any grounding electrodes present at a building must be used as part of the grounding electrode system.

    An underground metallic water pipe with at least 10 feet in contact with the ground is by definition a grounding electrode and must be used. It has to have supplementary grounding electrodes, like a UFER or ground rod(s).

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  6. #6
    Join Date
    Mar 2007
    Location
    Santa Rosa, CA
    Posts
    3,035

    Default Re: Grounding Electrode ?

    Quote Originally Posted by Bill Kriegh View Post
    GArt 250.50 states that any grounding electrodes present at a building must be used as part of the grounding electrode system.
    Bill,

    Apparently, I had never read it that way. Thank you!

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  7. #7
    Join Date
    Mar 2007
    Location
    Fletcher, NC
    Posts
    27,646

    Default Re: Grounding Electrode ?

    I disagree to the extent that Bill's statement is given as a blanket statement without the qualifier stated in the code (as I remember it - we are still unpacking from our move to Fletcher, NC, so my codes are still packed).

    The qualifier was about being made electrically continuous as I recall.

    I remember years ago there was debate on that wording, for example: does that wording mean 'made electrically continuous for at least 10 feet', or do it mean 'electrically continuous to the structure'?

    I.e., given this condition as an example: older home with a metal water pipe for the water service pipe, repairs were made replacing a bad section of the metal pipe with PVC, leaving the rest of the metal underground water pipe in place.

    Is the isolated section of metal underground water pipe (which is still over 10 feet long) still a grounding electrode?

    That code section also, as I recall, addressed metal well casings, but only if they were bonded to the metal water pipe (or wording like that).

    If an unbonded metal well casing (which would make an excellent grounding electrode going way down into earth and being below permanent water level) is exempted if not bonded (not electrically continuous), then isn't an unbonded and not electrically continuous metal water pipe also exempted?

    The answer in those AHJ was to the effect of 'yes, of course, if not electrically continuous to the structure'.

    Debatable?

    Sure, but to do otherwise means that every metal underground water pipe which is repaired with PVC would require an electrician to bond out to the remaining section of metal underground water pipe ... and to verify there was at least 10 feet of length to it.

    Jerry Peck
    Construction Litigation Consultant - Retired
    www.AskCodeMan.com

  8. #8
    Join Date
    Mar 2007
    Location
    Santa Rosa, CA
    Posts
    3,035

    Default Re: Grounding Electrode ?

    Jerry,

    I also seem to recall that the GEC connection to the metallic water pipe is required to be within 5 feet of where the water supply enters the building. If I am correct, and if this repair was more than 5 feet out from the house, it could not function as the grounding electrode.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  9. #9
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    682

    Default Re: Grounding Electrode ?

    Of course the qualifier needs to be taken into account. If the metallic pipe doesn't enter the structure it's not considered a grounding electrode because it can't be connected within 5 feet of where it enters the structure. I've never seen a requirement that required the metallic pipe that penetrates a foundation (or goes under it ) is required be installed AS an electrode. If it meets the requirements, so be it. But.............

    If a water supply in metallic pipe enters a structure, and is continuous for 10 or more feet it is considered a grounding electrode. If that pipe is repaired closer to the structure than 10 feet with non-metallic parts it is no longer continuous and no longer a grounding electrode, and no requirement to make it so. Since this type of electrode must have an additional electrode (used to be just a ground rod or other electrode, now 2 rods required if rods are used) installed as well, so you drive a second ground rod and go home. There is no requirement that a non metallic repair be jumped as long as the minimum requirements for electrodes are met.

    I'm not sure why you'd be digging to find metallic pipe that didn't enter the structure.

    Anyway, UFERS and non metallic water supply pipe are two of the best thing to come along in years. They solve a few potential future problems from the get-go.

    All that said,it is reasonably within the possibility that the remaining metallic pipe that enters the structure could become energized by any number of crazy things and should be bonded. (things like that buried cable to a shed getting nicked, or pin-holed by lightning and shorting to the pipe)

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  10. #10
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    682

    Default Re: Grounding Electrode ?

    Of course the qualifier needs to be taken into account. If the metallic pipe doesn't enter the structure it's not considered a grounding electrode because it can't be connected within 5 feet of where it enters the structure. (not present) I've never seen a requirement that required the metallic pipe that penetrates a foundation (or goes under it ) be installed AS an electrode. If it meets the requirements, so be it. But.............

    If a water supply in metallic pipe enters a structure, and is continuous for 10 or more feet it is considered a grounding electrode. If that pipe is repaired closer to the structure than 10 feet with non-metallic parts it is no longer continuous and no longer a grounding electrode, and no requirement to make it so. Since this type of electrode must have an additional electrode (used to be just a ground rod or other electrode, now 2 rods required if rods are used) installed as well, so you drive required ground rod(s) and go home. There is no requirement that a non metallic repair be jumped as long as the minimum requirements for electrodes are met.

    I'm not sure why you'd be digging to find metallic pipe that didn't enter the structure.

    Anyway, UFERS and non metallic water supply pipe are two of the best thing to come along in years. They solve a few potential future problems from the get-go.

    All that said,it is reasonably within the possibility that the remaining metallic pipe that enters the structure could become energized by any number of crazy things and should be bonded. (things like that buried cable to a shed getting nicked, or pin-holed by lightning and shorting to the pipe)

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  11. #11
    Join Date
    Mar 2007
    Location
    Garland, TX
    Posts
    641

    Default Re: Grounding Electrode ?

    mike holt offers free code graphics and ques of the day
    as it happens today's addresses this topic in a way

    https://www.mikeholt.com/dailycodegraphicquestion.php

    GEC Water Pipe.jpg

    badair http://www.adairinspection.com Garland, TX 75042 TREC # 4563
    Commercial-Residential-Construction-EIFS-Stucco-ACMV-Infrared Thermography
    life is the random lottery of events followed by numerous narrow escapes

  12. #12
    Join Date
    Oct 2014
    Location
    Maryland, DC, and Northern Virginia, electrical only
    Posts
    203

    Default Re: Grounding Electrode ?

    Consider 250.52(A)(8). Depending on your interpretation of "local," that underground well casing could qualify as a "metal underground structure" that must be treated as an electrode. How about that 10 ft metal underground water pipe that was separated from the rest by a chunk of PVC or pex and so is no longer bonded to the [building's] water pipe? Seems to qualify as well.


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •