Connect with us

Supplemental Ground Rod Bonding Question

Discussion in 'Electrical Engineering' started by RFI-EMI-GUY, May 27, 2008.

Scroll to continue with content
  1. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    I have a house in Florida built in 1980's. There is an underground
    service entrance, a meter can and a main disconnect panel which serves
    the sub panel in the house as well as a few circuits outside (pool pump
    and pool lights). There is a ground rod bonded to the meter can. (main
    ground rod)

    I recently had a digital satellite antenna installed by Dish. The
    installer chose to ground the dish to my pool pump ground rod which
    appears to be isolated from the main ground rod.

    Due to the poor grounding by the Dish installer, I chose to install a
    series or rods around the sides and corner of the house encompassing the
    dish installation, pool pump, main electrical service and the
    telephone NIC box. (all these items to be bonded together) These ground
    rods were spaced about 12 to 16 feet apart and bonded with #6 solid
    copper conductor. After installing this supplemental ground system, I
    confirmed that several volt differential between the new supplemental
    system and the existing main ground rod (of unknown condition). This
    test done without bonding the new supplemental system to the existing
    main ground system.

    It will be far easier for me to bond this new system to the
    ground/neutral bus bar inside of the main disconnect panel than to work
    inside the meter can. (requiring breaking the seal and working with live
    conductors nearby).

    Will there be any code violation or concern by attaching this new ground
    system to the main panel as described above? Bear in mind, the
    ground/neutral bus bar is connected by the neutral conductor to the main
    ground in the meter can only a foot away.


    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  2. Tom Horne

    Tom Horne Guest

    It is perfectly acceptable to run the new Grounding Electrode Conductor
    (GEC) to the existing ground rod by adding an additional acorn clamp to
    that rod. I strongly recommend that you do not run the new GEC inside
    your home in order to terminate it. You are much better off if you keep
    the GEC outside your home. Don't make lightning energy pass through
    your service equipment enclosure on the way to earth.
     
  3. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    I do intend to bond them together. The question is whether (assuming the
    main ground rod is up to code)using the ground/neutral bus bar inside
    the main disconnect panel (to bond a supplemental ground system) is OK
    per NEC as opposed to bonding within the meter can. For sake of
    argument, I can bond the conductors outside the meter can and the main
    disconnect panel as well. I just prefer not to bond the supplemental
    ground system inside the meter can as it requires working within live
    conductors. (Please re-read my original post for clarity)

    The pool ground rod is for the pool pump casing. The pool and pump were
    added after the house was built.

    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  4. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    The new GEC would be bonded inside the main disconnect panel which is
    outside the house next to the meter can. There will be very little
    conductor (inductance) between the existing main GEC and the new
    supplemental GEC. I am not trusting of the 28 year old conductor from
    the meter can to the existing main GEC and so would not like to rely
    entirely on direct bonding of that existing ground rod*. Thus I have
    another conductor I wish to bring inside the main disconnect panel to
    bond the ground/neutral bus bar.

    *If I have work done in future that requires opening the meter can, I
    may want to replace the old conductor and at that time, I will have the
    utility company make the connections.

    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  5. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    The new GEC would be bonded inside the main disconnect panel which is
    outside the house next to the meter can. There will be very little
    conductor (inductance) between the existing main GEC and the new
    supplemental GEC. I am not trusting of the 28 year old conductor from
    the meter can to the existing main GEC and so would not like to rely
    entirely on direct bonding of that existing ground rod*. Thus I have
    another conductor I wish to bring inside the main disconnect panel to
    bond the ground/neutral bus bar.

    *If I have work done in future that requires opening the meter can, I
    may want to replace the old conductor and at that time, I will have the
    utility company make the connections.

    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  6. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    The new GEC would be bonded inside the main disconnect panel which is
    outside the house next to the meter can. There will be very little
    conductor (inductance) between the existing main GEC and the new
    supplemental GEC. I am not trusting of the 28 year old conductor from
    the meter can to the existing main GEC and so would not like to rely
    entirely on direct bonding of that existing ground rod*. Thus I have
    another conductor I wish to bring inside the main disconnect panel to
    bond the ground/neutral bus bar.

    *If I have work done in future that requires opening the meter can, I
    may want to replace the old conductor and at that time, I will have the
    utility company make the connections.

    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  7. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    Putting this into an even simpler context and assuming that I have a
    single point ground system (albeit many rods), is there anything in the
    NEC that prevents me from connecting the ground system at two points. 1)
    within the meter can at the neutral (as existing) and 2) within a short
    distance away, connecting to the ground.neutral bus bar inside the main
    disconnect panel.

    I can see a case where this may exist to the extreme:

    A pole mounted meter can, and some distance away, a house mounted main
    disconnect panel. Would it not be prudent to have a ground rod at each
    of those locations?


    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  8. ehsjr

    ehsjr Guest


    Bond ALL your grounding electrodes to create your
    "grounding electrode system". Connect the grounding
    electrode system via the "grounding electrode conductor"
    to the service per 250.24. From the 2005 NEC:
    "(A) System Grounding Connections. A premises wiring system
    supplied by a grounded ac service shall have a grounding
    electrode conductor connected to the grounded service conductor,
    at each service, in accordance with 250.24(A)(1) through (A)(5).

    (1) General. The connection shall be made at any accessible point
    from the load end of the service drop or service lateral to and
    including the terminal or bus to which the grounded service
    conductor is connected at the service disconnecting means."

    There is a single grounding electrode conductor - I got the
    impression that you might be thinking of bringing multiple
    conductors from the various electrodes into the panel and
    bonding them there. That's the wrong way - you can't have
    multiple GEC's.

    Ed
     
  9. bud--

    bud-- Guest

    Connecting inside the meter can would be more fun. Have someone standing
    appropriately far away taking pictures to post.

    My 1st choice would be to split-bolt the #6 bond wire to the grounding
    electrode conductor (GEC) in the vicinity of the meter. You sound like
    you wouldn't like that idea.

    The permissible connection locations are in 810.21(F) They include:
    - any point on the grounding electrode system (as above)
    - metal service raceway (like a ground clamp on EMT above the meter;
    below the meter more than normal bonding of the pipe is required)
    - grounded interior metal water pipe within 5 ft of the building
    entrance (10 ft min underground metal water service pipe should already
    be an electrode; else metal interior water pipe should already be bonded)
    - the meter enclosure or service disconnect enclosure.

    The ground/neutral bar of the service disconnect is not specifically
    included, but is substantially the same as the last item above (even
    though the GEC does not land on the bar).

    Ask the AHJ?

    The bonding wire should run in "as straight a line as practicable" and
    can be inside or outside.

    If the NEC is enforced for dish installs, the installer should have made
    this bonding run.
     
  10. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    I have pretty much satisfied myself that I will have: 1) a single point
    grounding system. The original ground rods and supplemental ground rods
    will all be bonded together at ground level and, 2) A redundant ground
    conductor which will terminate inside the main disconnect panel at the
    ground bus. I really don't trust the original ground conductor at the
    meter can and using a split bolt right at the meter can to bond the
    redundant conductor does not preclude the possibility of the main
    conductor loosening inside the meter can.

    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-