Results 1 to 10 of 10
  1. #1
    Join Date
    Mar 2007
    Location
    Cape Cod, Massachusetts
    Posts
    574

    Default Second ground connection

    Here's a remote panel located in detached garage. It is wired with four conductors from service equipment that is located in main house. The ground and neutral bars are isolated. The panel also has it's own ground connection to a ground rod that is not the same ground rod as the main house.

    Is the additional ground connection at the remote panel allowed?

    Similar Threads:
    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    F.I.R.E. Services
    Ken Amelin
    Cape Cod's Best Inspection Services
    www.midcapehomeinspection.com

  2. #2
    Join Date
    Mar 2012
    Location
    North Central Texas
    Posts
    472

    Default Re: Second ground connection

    Quote Originally Posted by Ken Amelin View Post
    Is the additional ground connection at the remote panel allowed?
    It is required to have its own ground as per NEC 250.32A, each building requires its own grounding electrode system.

    http://www.iaei.org/magazine/2004/01...-outbuildings/

    Texas Inspector
    http://www.texasinspector.com
    What the plainspoken man lacks in subtlety, he makes up in clarity.

  3. #3
    Join Date
    Mar 2007
    Location
    Cape Cod, Massachusetts
    Posts
    574

    Default Re: Second ground connection

    Thanks both of you for the quick reply. - Just in time for my report.

    Ken Amelin
    Cape Cod's Best Inspection Services
    www.midcapehomeinspection.com

  4. #4
    Al Neuman's Avatar
    Al Neuman Guest

    Default Re: Second ground connection

    The ground wire from the rod is connected in the wrong place.

    It should be terminated on the neutral bus.... Not the equipment ground bus.


  5. #5
    Gerry Bennett's Avatar
    Gerry Bennett Guest

    Default Re: Second ground connection

    Quote Originally Posted by Al Neuman View Post
    The ground wire from the rod is connected in the wrong place.

    It should be terminated on the neutral bus.... Not the equipment ground bus.
    Now you are going to open up a can of worms, but you are correct!


  6. #6
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Second ground connection

    Quote Originally Posted by Al Neuman View Post
    The ground wire from the rod is connected in the wrong place.

    It should be terminated on the neutral bus.... Not the equipment ground bus.
    Quote Originally Posted by Robert Meier View Post
    This is not a service, the bare GEC is terminated on the correct bus. It should not be on the neutral bus.
    Robert is correct.

    That is a remote panel/distribution panel/etc. and the neutral is not allowed to be bonded to ground.

    I also doubt that those main lugs are listed for that small of conductors.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  7. #7
    Gerry Bennett's Avatar
    Gerry Bennett Guest

    Default Re: Second ground connection

    Quote Originally Posted by Jerry Peck View Post
    Robert is correct.

    That is a remote panel/distribution panel/etc. and the neutral is not allowed to be bonded to ground.

    I also doubt that those main lugs are listed for that small of conductors.
    Excuse my post It was wrong! I looked at it quickly and thought of a job I did. It was a detached garage with an existing overhead 3 wire triplex wiring. The inspector (more than one) said to make it right add a ground rod but don't isolate the ground from the neutrals.
    I am going to check later the reason for that,maybe someone knows.

    Last edited by Gerry Bennett; 10-05-2012 at 03:35 PM. Reason: adding 250.32 B exception1

  8. #8
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Second ground connection

    Quote Originally Posted by Gerry Bennett View Post
    It was a detached garage with an existing overhead 3 wire triplex wiring. The inspector (more than one) said to make it right add a ground rod but don't isolate the ground from the neutrals.
    I am going to check later the reason for that,maybe someone knows.
    Triplex has 2-hot conductors and 1-groundED conductor, but 0-groundING conductors.

    Older detached garages (separate buildings) were allowed (under certain conditions) to be fed with triplex wiring at that time.

    The grounded conductor served as the groundED neutral and the groundING conductor, as such, the groundED neutral was connected to the GEC going to a grounding electrode at the separate building.

    The certain conditions were that there was *no* metallic path of any kind between the buildings, no phone cable, no intercom cable, no metallic water piping, *no* metallic paths between the two.

    With a 4-wire feed, an equipment ground is now run with the feeders, and if the groundED neutral conductor was bonded to the GEC going to the grounding electrode, then the neutral current would try to take both paths back to the source, i.e., some neutral current would go on the intended neutral conductor, however, some neutral current would also go on the unintended GEC to the grounding electrode and to earth, then back to the source.

    That is the reason why.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  9. #9
    Gerry Bennett's Avatar
    Gerry Bennett Guest

    Default Re: Second ground connection

    Quote Originally Posted by Jerry Peck View Post
    Triplex has 2-hot conductors and 1-groundED conductor, but 0-groundING conductors.

    Older detached garages (separate buildings) were allowed (under certain conditions) to be fed with triplex wiring at that time.

    The grounded conductor served as the groundED neutral and the groundING conductor, as such, the groundED neutral was connected to the GEC going to a grounding electrode at the separate building.

    The certain conditions were that there was *no* metallic path of any kind between the buildings, no phone cable, no intercom cable, no metallic water piping, *no* metallic paths between the two.

    With a 4-wire feed, an equipment ground is now run with the feeders, and if the groundED neutral conductor was bonded to the GEC going to the grounding electrode, then the neutral current would try to take both paths back to the source, i.e., some neutral current would go on the intended neutral conductor, however, some neutral current would also go on the unintended GEC to the grounding electrode and to earth, then back to the source.

    That is the reason why.
    Thanks for that clear answer. We are required when doing a service ground to "jump" the meter, ground clamp below the meter, a loop and a ground clamp above the meter. The reason I heard was on occasion the water meter service man would receive a shock when he removed the meter for replacement. Would this also be some unintended neutral current?


  10. #10
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Second ground connection

    Yes, it could be, but it might also be unintended current from a ground-fault. It could also be both.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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
  •