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    What is lightning arrestors in a Lightning protection system?


    Are you interested in knowing all about lightening arrestors? Searching for detailed information including its use, how it is used in the lightening protection system, its range of coverage etc.? On this Ask Expert page check out the responses from experts for all your queries.

    If you have noticed on tall or high rise buildings and even on top of churches, temples or chimneys, we can see a tri-shaped rod called the lightning arrestors. Many of us many not no the use and its advantage and thus I would like our experts to provide more details on the same with respect to the following questions:
    a) What is a lightning arrestor and its use?
    b) Why is lightning arrestor used in a Lightning protection system?
    c) What is the range or coverage of a normal lightning arrestor?
    d) What is the working or function of a lightning arrestor?
    e) What are the components of a lightning arrestor or Lightning protection system?
    f) What is the cost of installing a lightning arrestor for a small(upto 750 sq.ft), medium(upto 1800 sq.ft) or big house((above 1800 sq.ft)?
  • Answers

    2 Answers found.
  • It is a device used on electric power systems and telecommunication systems. When there is the lightning heavy voltage of power will be released and if it comes in contact with any electrical appliances or telecommunications this voltage will damage them. Sometimes because of this high voltage, many untoward incidents will also take place. To control these accidents lightning arrestors are used. They will change the path of the heavy voltage so that they will ground safely and no equipment will get spoiled. It protects the insulation and conductors of the system from the damaging effects of lightning.

    A lightning arrester is supposed to have the characteristics that are mentioned below.
    1. It should not draw any current during the normal operating condition, i
    2, Any t abnormal voltage must be broken down so that it may provide a conducting path to ground.
    3. While doing this activity it should not get damaged.
    Many types of lightning arresters are known. The choices will depend on the factors like voltage and frequency of the line, cost, weather condition, and reliability.

    The cost of lightning arrestors will depend on the area of the building and the purpose. The cost may vary from Rs.5000/- for a single arrestor to more than a lakh of rupees based on the area. There will be s special design for these protection systems installation which involves a large coverage area with fewer arrestors.

    drrao
    always confident

  • During storms and bad weather, lightening is a common phenomenon and sometimes it is so severe that the electric charges generated by the cloud collisions create a big electric field which tries to reach ground for its dissipation and if any big building or tree or structure comes in between the electric field burns it with its high strength and destruction takes place immediately. Let us go through the answers to the question sequence wise -

    a) Lightening arrestor is a metallic rod provided at the top of a structure and is connected to the ground through a conducting cable or wire so that in case some lightening strikes on it the electricity takes the least resistance path of the rod and wire and goes to the Earth. The potential of Earth is at zero level and it accepts the tremendous electrical charges easily and absorbs them. In every house there is an Earth connection which goes to the Earth and in case of any electricity leakage in the house it goes to the Earth. The same privilege goes to the lightening arrestor also. It is a great safety device.

    b) Lightening arrestor is used for protection of the high rise structures to save them from destruction. It is a safety device.

    c) Whenever a thunderbolt comes near the lightening rod it would give it an easy path of travelling and the electric current would flow to the ground through the electrical wire. There is nothing like a range for it but yes in presence of a lightening conductor on the top of a high rise structure some nearby shorter structures might come in its shadow and can remain inactive though they would also have their own lightening protection rods and systems in place.

    d) The working of the lightening conductor is based on the principle of least resistance for the flow of electricity. Remember the instantaneous electric current can be of the order of thousands of Amperes but the lightening system will allow it to flow to the ground smoothly. Though in some severe cases the lightening system itself is found as charred or incinerated by the high electric currents. Those are rare instances.

    e) The lightening arrestor system has 3 components. First is the rooftop rod conductor. This is a long rod slightly sharp at the upper end and is fastened firmly on the highest point. Then second part of the system is the electric wire of sufficient diameter which is connected to the bottom of this rod and then from the outside of the building it traverse down to the ground. The third part of the system is the ground rod or mesh which is kept in a dug hole and after connecting the wire to the top of that it is to be sealed from the top and we would see only a wire going inside the Earth.

    f) A complete lightening arrestor system for a medium house would cost in the range Rs 1500 to 5000 depending upon the quality and design. Copper is a very good conductor of electricity and is used for this purpose.

    Knowledge is power.


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