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Thread: Lightning protection for site/roadway poles-what works?

  1. #1
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    Lightning protection for site/roadway poles-what works?

    I have a client with 40 - 35' poles on their site. Since this facility was built 2009 they have had 5 storms come through and cause significant damage to lamps, ballasts, and pole conductors. What can be done to increase isolation from lightning direct or indirect strikes?

  2. #2
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    Welcome to the Forum!

    What are on the poles, what are all the poles used for, what's the circuit runs like, please describe all the equipment that's in service. Are these all metal or a "telephone pole"?

    The only isolation thought for me is not to run metal conduit between poles, change to a lower pole use a lower profile lamp but be it a broadcaster of light!

    How's the Area look in respects to 2012 ? It just seems that nothing been spared in this country or missing any weather as of late!

    The NFPA 780 covers; Standard for the Installation of Lightning Protection Systems.

    Good Luck!
    If your even thirsty, your two quarts low.

  3. #3
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    Lightning protection for

    What are on the poles-35' square metal, cutoff fixtures, what are all the poles used for-site lighting, what's the circuit runs like-20A/3P with 480V-2P lamps-circuits loaded to 10 amps in PVC, please describe all the equipment that's in service-500' to 1500' circuits with TVSS at building.

  4. #4
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    Lightbulb

    One option would be to install an overhead ground wire system between all the poles located on the property. This is sometimes referred to as a "faraday cage" or "catenary wire" lightning protection system. This can be seen at military installations and other hazardous occupancies.

    Some guidance can be found in ANNEX G.1.2 of the NFPA 780. An example of this protection method can be found at FIGURE 7.3.3.2 of the NFPA 780.
    Bryan P. Holland, MCP

  5. #5
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    I got a quote from Erico and they do lightning protection for a living.... If you need something that will work 100% you can talk to them.


    https://docs.google.com/leaf?id=0B6s...thkey=CJfS6c0G

  6. #6
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    Ground rod at each pole connected to a rod at the top of the pole. That's the simplest. The effectiveness could be questionable depending on if the pole grounded through the base has a lower resistance than the ground wire to ground rod.

    I suppose you could use shield masts and/or shield wires like in a substation, but that is probably not practical, and possibly not viable.

    Could look into changing to concrete or fiberglass poles.
    "Just because you're paranoid, doesn't mean they're not out to get you"

  7. #7
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    lightning protection

    Usually the vendor supplying the pole sells lightning rod attachments for the top of the pole. There would be a ground wire run internally to the base of the pole and attached to a groundlug or plate. This in turn is connected to a ground rod.

  8. #8
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    Quote Originally Posted by guggemos View Post
    Usually the vendor supplying the pole sells lightning rod attachments for the top of the pole. There would be a ground wire run internally to the base of the pole and attached to a groundlug or plate. This in turn is connected to a ground rod.
    Seldom do these type of failures due to direct lightning strikes, but induced currents as the strike travels through the pole. The traditional lightning 'protectors' actually increase the strike potential as they attract the strike to be conducted through them by providing a low impedance path, thus the induced current damage could potentially increase.

    We have found the highly controversial LEC systems to be an effective solution. We installed a comprehensive system over one of our largest plant that suffered 2-3 strikes and subsequent plant shutdowns. That happened 5 years ago and we experienced no shutdowns related to lightning strikes hence. The Waisala nationwide strike monitoring system actually indicated slightly increased strike density for some of the years in the area.

    We also had similar experience with smaller installations, but those were not as well researched/documented after the fact, just the comment: "we no longer seem to have a problem with lighting."

  9. #9
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    Lightbulb

    Quote Originally Posted by weressl View Post
    The traditional lightning 'protectors' actually increase the strike potential as they attract the strike to be conducted through them by providing a low impedance path, thus the induced current damage could potentially increase.
    Sorry, but this is a false statement. "Traditional" lightning protection systems do not attract nor prevent a strike from occuring. The presents of or lack of a LPS on a structure does not and can not indicate if a strike will occur at some point in the future. A properly installed LPS does not increase the potential for damage, but MAY help to mitigate or reduce any potential damaged.



    We have found the highly controversial LEC systems to be an effective solution.
    Any component of or method of installation of a LPS not recognized by the NFPA 780 or other nationally recognized lightning protection standard should not be considered, regardless of the claims made by the manufacturer and/or installers. Devices and equipment that are not listed to the ANSI/UL96A standard should also be discounted.

    While I am not an authority on the LEC Dissipation Array System, I can assure you there are as many studies showing the ineffectiveness of these systems as there are claims that they actually do work. Any one considering a non-conventional system should first consult their insurance provider and research the system fully before committing.
    Bryan P. Holland, MCP

  10. #10
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    Quote Originally Posted by bphgravity View Post
    Sorry, but this is a false statement. "Traditional" lightning protection systems do not attract nor prevent a strike from occuring. The presents of or lack of a LPS on a structure does not and can not indicate if a strike will occur at some point in the future. A properly installed LPS does not increase the potential for damage, but MAY help to mitigate or reduce any potential damaged.
    Incorrect. Traditional lightning protection system DOES provide a low impedance 'attraction' point. That is the WHOLE purpose of it! The fundamental provision for a strike to occur is a low impedance path from the two charged objects - earth vs. cloud - and that is what the lightning rod provides compared to all other objects in the surrounding area. The charges are not stationary, but move along as the clouds blown by the wind. When the charges are high enough and the atmospheric discharge conditions optimal and a low impedance path is found, the strike occurs. So if a low impedance point is intentionally established that point will be more likely to be struck by lightning than others within a given area.




    Quote Originally Posted by bphgravity View Post
    Any component of or method of installation of a LPS not recognized by the NFPA 780 or other nationally recognized lightning protection standard should not be considered, regardless of the claims made by the manufacturer and/or installers. Devices and equipment that are not listed to the ANSI/UL96A standard should also be discounted.

    While I am not an authority on the LEC Dissipation Array System, I can assure you there are as many studies showing the ineffectiveness of these systems as there are claims that they actually do work. Any one considering a non-conventional system should first consult their insurance provider and research the system fully before committing.
    LEC offered system is UL listed. I have shared my experience, that's all. I used to be a sceptic, but I find it hard to argue with facts and try to explain it away. Prof.(Emeritus) Moore of the Univ of Minessota, one of the foremost authority on lighting, had clearly acknowledged that while there is insufficient scientific understanding of what seems to occur with these systems, there is evidence that merits future work. So did Prof. Besleayan et al. None of the 'studies' that attempted to disprove the systems actually used the hardware, but conducted various statistical gymnastics. Studies need to be funded.

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