Results 1 to 5 of 5

Thread: Ground Rod/conductor Size for Site Lighting

  1. #1
    Join Date
    Aug 2010
    Location
    Metro DC
    Posts
    27

    Ground Rod/conductor Size for Site Lighting

    Drawing detail for site lighting calls for 10' x 3/4" ground rods at concrete bases for parking lot lighting and bollard style walkway lighting for new retail building construction project. Detail also shows #8 bare copper bonding metal pole to ground rod. I assume engineer called for this to limit potential lightning damage. Crew installed 8' x 5/8" ground rods into poured bases by mistake. We do have equipment grounding conductors pulled in with circuit conductors. My question is: Will 8' ground rods with #8 copper be sufficient for intent or do we need to go back and install 10' x 3/4" with # 8 copper. I question the size of the #8 grounding conductor also. Thanks for feed back.

  2. #2
    Join Date
    May 2005
    Location
    Redmond, WA
    Posts
    783
    In my opinion, the concrete encased 8' rod is a much better ground than a single 10' rod. But my opnion doesn't count.

    If the engineer/owner/inspector doesn't accept the installtion, try doing a ground resistance test comparing a single 10' rod and the foundation. Isolate the EGC so the test is reading just the one foundation/rod.
    Bob Wilson

  3. #3
    Join Date
    Jan 2009
    Location
    Easton, Maryland NEC: 2011
    Posts
    7,881
    While specs should be followed and you may be dinged for that, the rods are just extra and not required by the NEC.

    You pulled an EGC right?

    Why do you question the #8?
    "Electricity is really just organized lightning." George Carlin


    Derék

  4. #4
    Join Date
    Aug 2010
    Location
    Metro DC
    Posts
    27
    Yes, equipment grounding conductors were pulled in with circuit conductors separately. I questioned the #8 conductor as being underrated for capacity to the 10' rod but fine for the 8' rod?

  5. #5
    Join Date
    Oct 2006
    Location
    Litchfield, CT
    Posts
    8,622
    Why don't they just spec more concrete if someone is so worried about it? What on earth (pun intended) does a rod do differently then the concrete form?
    "Electricity is actually made up of extremely tiny particles called electrons, that you cannot see with the naked eye unless you have been drinking."

Posting Permissions

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