Lightning Protection FAQ's

FREQUENTLY ASKED QUESTIONS
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    (1) Is there any need for protection against direct lightning strikes?
    The research done and data published by reputed International Agencies like NASA, National Geographic etc,, have conclusively proved that there is an Enormous increase in the lightning activity all round the World due to various phenomena like Global Warning, etc. This has resulted in our building and other assets being more vulnerable to damage due to lightning than ever before. Besides the prevailing regulations, mandate the provision of reliable lightning protection system for all structures and buildings of 12 Mts and above. Hence, it is important that all our important buildings and structures be protected by using a reliable Lightning Protection System.
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    (2) What are the different methods of lightning protection and their Merits / demerits?

    Presently, there are 2 methods of Lightning Protection System being adopted in India. These are:

    1) Conventional Mesh / Franklin Rod System:
    In this method, a large number of Franklin rods and the strips are to be installed on the terrace and connected to the earth for the purpose of lightning protecti

    2) Early Streamer Emission System:
    In this method, generally one ESE lightning rod will be installed on the terrace and connected to the earth for the purpose of Lightning Protection.

    In comparison, the ESE lightning rods are active systems. Here, either one or a very small number of lightning rods to be used (for the same area) to provide the highest degree of protection. A detailed comparison between conventional systems and ESE systems can be furnished on request.

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    (3) What is the standard applicable for the lightning rods working on the ESE principle?

    The accepted standard world wide (more than 100 countries all over the world) for the lightning rods working on ESE principle is the French standard NFC 17102 and the Spanish standard UNE 21186.

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    (4) Are all ESE lightning rods the same?
    No. Though the fundamental principle of all ESE lightning rods is the same (that of generating an Early Streamer Emission), the technology used to generate the streamer may vary. Some of the ESE lightning rods available in the country work on obsolete technologies like Piezo Electric Technology, Simple Dielectric Technology, etc. However our NIMBUS Lightning Rod works on the state of the art (latest generation) High Voltage Pulse Emission Technology.
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    (5) Does the Nimbus require any form of external power supply for working?
    No. The Nimbus does not require any form of external power supply like external DC/AC supply or battery for its working. The Nimbus is a self powered device which captures the energy induced naturally by the impending lightning strike, stores it and generates the upstreamer using the stored energy.
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    (6) Am I unnecessarily attracting all lightning strikes from the surrounding areas by installing the Nimbus?

    No, the ESE rod does not unnecessarily attract the lightning strikes from surrounding areas. The Nimbus is designed to capture all lightning strikes within the area intended/ designed to be protected only and not from the surrounding areas.

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    (7) Will installing the Nimbus lightning rod cause any interference to the other electronics / electrical equipment in the vicinity?
    Since the Nimbus lightning rod emits the charged pulses only for a few micro seconds, there is practically no interference with the other electronics / electrical equipments located in the vicinity.
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    (8) Can the Nimbus lightning rod alone protect all equipments housed in my structure from damages due to lightning strikes?

    The Nimbus lightning rod can only protect the structure and the people from the direct impact to the light strike. The damage to equipments housed inside the structure occurs because of the transient voltage surges caused by a lightning strike. The Nimbus lightning rod does not offer any protection against these surges.The equipment housed inside the structure will have to be protected , by installing a separate Surge Protection System.

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    (9) How can I know if the Nimbus has actually captured a lightning strike?

    A lightning discharge counter (supplied optionally) will record all the instances of lightning strikes captured by the NIMBUS Lightning Rod. Hence, by installing a lightning discharger counter, the exact number of lightning strikes captured by the Nimbus can be known

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    (10) Will the Nimbus lightning rod provide 100% security on my installation from all lightning strikes?
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    (11) How do I design the proper lightning protection system for my system?
    At Jef , we help you design the appropriate LPS for your structure according to the guidelines laid down by the governing standards. This activity will include a detailed risk analysis of the assets, coverage drawings, models of lightning rods required to be installed etc. We also take up supply and installation of the Lightning Protection System wherever the client desires. More details on this can be made available on request. If you require an assistance, please get in touch with our branch office closest to you.
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    (12) What is the life time of the Nimbus lightning rod?

    All the components used in the Nimbus lightning rod have a design life of approximately 15 to 18 years. The design life of the Nimbus lightning rod as claimed by the manufacturer is 15 years. However, the commercial guarantee is , 18 months from the date of supply.


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    (13) Is the Nimbus capable of working in corrosive atmosphere or high temperature areas?

    The body of the Nimbus is made of AISI 316 grade stainless steel which is highly resistant of corrosion. Further, the electronics are encapsulated in an epoxy mould. Epoxy material being resistant to temperature and also a very bad conductor of heat, the outside temperature will not reflect on the electronic components housed outside. Hence, the Nimbus is fully capable of working in corrosive atmosphere and high temperature and high temperature areas upto 120 ËšC

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    (14) Can the Nimbus be installed directly at Chimney or Vent?

    The Nimbus is not recommended to be installed at top of the chimney or vent. Specially, in case of a vent which is emitting flammable or explosivegases, it is recommended to install the Nimbus on a near by structure which is taller than the vent to be protected and a safe distance away from the vent.

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    (15) What is the best way to protect a tall chimney or vent?

    Since the tall Chimneys or vents are always structures with a narrow base, the conventional Franklyn Rods are ideally suited for protecting them. The conventional rods are also not affected by the temperature of the flue gases / other emissions of the chimney. However, it is to be noted that the conventional rods only protect these chimneys / vents and not the structures around them. This is because, as the height of mounting of the Franklyn rod increases, its angle of coverage reduces drastically.

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    (16) At what height should the Nimbus lightning rod to be mounted on a building/structure?

    The Nimbus lightning rod should ideally be mounted such that the tip of the Nimbus is 5 Mts above the highest and farthest plane on the structure to be protected. However, the Nimbus lightning rod should be at least 2 Mts above any other point on the structure to be protected (like Antenna, Cooling Systems of Air Conditioners, etc) to avoid flashovers.

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    (17) What is the area covered by each Nimbus lightning rod?

    The area covered by each Nimbus lightning rod varies depending on the level of protection and the height of mounting. Please refer to our catalogue to know the exact radius of protection offered by different models of the Nimbus lightning rod for different levels of protection and heights of mounting.

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    (18) Does the Nimbus lightning rod need any special insulated high voltage cable for its working?

    The Nimbus lightning rod does not require any special high voltage cable to be used as down conductor for its working. In fact, the governing standards for the ESE lightning rods, (The NFC-17-102), have specifically forbidden the use of such down conductors.

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    (19) Is the Nimbus lightning rod compatible with the existing GI Strip down Conductors and normal earth terminations?

    The Nimbus lightning rod is fully compatible with the GI strip down conductors and normal earth terminations. However, the resistance of the earth termination shall be less than 10 Ohms and the GI strip down conductor have at least 150 Sq.mm cross section area.

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    (20) How many down conductors should be used for a given installation?

    As per the standards , one down conductor shall be used where the building height is less than 28 Mts and 2 down conductors for building height more than 28 Mts. Also, of the width of the building is more than 2 times its height, then 2 down conductors are to be installed. However, from the point of view of safety it is recommended to have at least 2 down conductors for every installation irrespective of the height of the structure.

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    (21) What is the cross section of Down Conductor that should be used?

    If a copper down conductor is used, the cross section shall be at least 50 Sq.mm. If GI down conductor is used, the cross section should be at least 150 Sq.mm.

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    (22) What is the profile of the Down Conductor to be used?

    It is advisable to use a flat down conductor instead of a circular down conductor. Since the lightning current is of a high frequency and consequently exhibits skin effect, a flat down conductor offers more surface area for the current to flow as compared to a circular down conductor.

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