New Grounding Requirements

Discussion in 'Design, Development and Standards Discussions' started by Jeff Toney, Jan 6, 2008.

  1. Jeff Toney

    Jeff Toney Friend of the Community

    I would like to see an example of how to ground a monopole using six ground rods installed symmetrically around a monopole with a minimum of 20' spacing.

    A ground ring is usually installed around the monopole foundation approx 2' from the foundation with two or three ground rods. It is then tied to the shelter ground ring.

    I am having trouble visualizing how this is going to work on a site with more than one carrier.

    Any ideas or web sites I can check out??
  2. Wireless Estimator

    Wireless Estimator Administrator Staff Member

    You bring up an interesting question, Jeff. The standard states that: For self-supporting structures the default grounding configuration shall be a minimum of six grounding electrodes installed symmetrically around the base of the structure at a minimum 20 ft [6m] spacing. A minimum of one lead shall be connected to each leg for latticed structures and a minimum of three leads shall be symmetrically connected to the base for pole structures.

    There appears to be no specification on the diameter of the ground ring. However, when you space the electrodes every 20? it would require a 40?X40? area which is considerably larger than some lease footprints. The electrodes and tails could also extend under BTS foundations where available space is at a premium on high capacity sites. It would be helpful to hear from an A&E firm as to how they will address the new requirement.
  3. Jeff Toney

    Jeff Toney Friend of the Community

    I do work for an A&E firm that designs tower sites in Ohio. I am wondering what the authors of Rev G envisioned the grounding to look like at a typical raw land site with multiple carriers?!

    It would be interesting to hear from someone involved in the development of Rev G.
  4. Bob Hardee

    Bob Hardee Friend of the Community

    As a former site acquisition manager, I believe this new rule will create many new challenges for finding and acquiring suitable tower sites.
    Since the area for grounding will greatly increase, in order to have room for multiple equipment pads and shelters, a much larger lease area will be required. As most sites where zoning has historically been allowed are very limited in space, the rule greatly reduces or entirely eliminates potential sites in many urban areas, the precise locations where they are most required.
    When suitable sites are found, the cost will also increase due the the expanded land requirement. Most existing sites in these locations have already been maxed out.
    Bob Hardee
  5. Jerome Levy

    Jerome Levy Industry Observer

    I think what you are going to see is the TIA committee starting to work on Rev. H in the near future. Whenever there are major changes like we had in Rev. G, there will bound to be areas that could have been tweaked as engineers outside of the committee get a chance to contribute their information as they review each section, such as the obvious spacing disparity for the ground rods. When Rev. D came out, which was also a major change, Rev. E wasn't too far behind.

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