Lightning flashes are common in bad weather with thunderstorms. To protect yourself from lightning, you generally move inside your home or business. But what if lightning strikes these buildings? When lightning strikes a building, it travels through these buildings to find a path to the ground. It will pass through the electrical wires and electronic devices that are plugged into your home or business. Thus, it can cause a fire that may harm people and property. So, to offer protection against lightning, you can install lightning rods in-home or business structures and do a lightning rod test often to make sure of its function.
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What is a Lightning Rod?
Lightning rods, also known as lightning conductors, are rods made of metal. Benjamin Franklin first developed these rods. You can mount this metal rod on any structure. It helps to protect the building or any other structure from lightning strikes. The rod connects to the ground with the help of a cable or wire. The rod is generally 2cm-2.5cm in diameter. When lightning strikes the building, it will first strike the rod. As a result, the lightning goes into the ground without passing through the building. You can also name lightning rods as air terminals, strike termination devices, or finials.
A lightning rod can be of any conductive material. This can be either copper or aluminum. Mostly, lightning rods are made up of copper and alloys. It is available in different forms like hollow, flat strips, rounded, solid, or pointed. Do not use rods with poor conductivity. Whatever is the form, a lightning rod functions only if it has a connection to the earth.
How Does a Lightning Rod Work?
Generally, people believe that lightning rods attract lightning. However, that is not true. These rods provide a safe, low-resistance, and alternate path to lightning’s high voltage electric currents. The lightning protection system prevents structural damage due to a voltage spike. In addition to this, it also prevents the failure of internal systems. If lightning strikes any surface with poor conductivity, it can cause physical damage to that surface. Being a good conductor, rods give a safe path to the ground without causing any lightning damage.
When lightning strikes, it jumps around. The “jumping” occurs due to the difference in strike target voltage and the earth voltage. Whenever lightning strikes, it always looks for the lowest resistance path. If the strike occurs near a lightning protection system, it will offer a low-resistance path. As a result, it will get a jump that diverts the strike to the ground safely. Even if it is not a direct strike, the conductors will pick the current.
Image: lightning rod against a cloud dark sky
Typical Residential Lightning Protection System
If you want to protect an open structure, you need to take a very tall lightning rod. Make sure that the rod is taller than the building or structure. If there is a strong electric field, this tall rod will send positive steamers to disperse the electric field. It’s not that the rod will always conduct the lightning, but it will do much better than the structure. The main aim is to provide a lightning strike a low resistance path to the ground. A good lightning protection system ensures complete safety from lightning strikes.
When there are flat roofs, you have to install rods along the perimeter. In the case of sloped roofs, you must install lightning rods along the peaks. The lightning protector can have round or pointed ends. Further, the height of the lightning protector with respect to the structure and the earth decides its efficiency.
When you install a lightning protection system, you must take care of adjacent structures. There should not be anything that is 50 feet above the adjacent structures.
Image: house lightning rod system
Why is the Maintenance of Lightning Rods Important?
If you install lightning rods, you must do periodic inspection and maintenance. Many national and international regulations suggest the maintenance procedure. During maintenance, you can detect deviations from reference standards. Also, you can detect any other issues that occurred due to an atmospheric condition. For example, corrosion, incorrect handling, or expansion of buildings may affect lightning protection components. These can also change the installation structure of lightning rods.
In the absence of maintenance, lightning rods may not work properly when required. As a result, you fail to stop the harmful effects of lightning. The different parts of lightning rods worsen over time. Thus, you must make sure that each part is in good condition.
Image: Short circuit protection or lightning protection system for mobile phone substation
Here is what you need to check during maintenance activity.
- Make sure that rods are working fine. When there is early streamer emission (ESE), the upward leader emitting elements must be operational.
- Down conductors should have continuity all time. Further, they should be fixed to avoid any breakage or sparks.
- Make sure that ground resistance values are below 10 ohms. This dissipates harmful currents quickly. Further, it also minimizes return currents and contact voltages.
How do you do Lightning Rod Revision?
The maintenance procedure of complete lightning protection systems includes
Visual inspection: During the visual check, you must confirm that
- Lightning rod has no damage due to lightning strikes
- All the elements of the rod are in a good state
- Conductors have good continuity
- Fixings are working fine
- Any damage due to corrosion
- Equipotential bonding is right
Manufacturers put certain specifications to the lightning rods. During maintenance activity, you must verify that the electrical continuity of down conductors is in good condition. You must also check the correct performance of air terminals in the case of ESE. Checking air terminals is difficult as well as risky. This is because you install rods at least 2 meters above any building or structure that you need to protect. Thus, it becomes difficult to reach the air terminals, and the operator is also in danger while performing these inspections.
Further, you need to check the earthing system. For this, you must check earth resistance. Make sure that it is always below 10 ohms. You must check the earthing annually. If you record high earth values, you must use a conductive plus. Or you can install a system that has more earth rods.
Additionally, you need to check all the electrical lines that need protection against high voltages. You must also do ground testing to check the ground rod’s functionality.
If you detect any issues or deterioration during an inspection, you must carry out important corrective measures as soon as possible to ensure maximum protection.
Further, the person who conducts this inspection must prepare a report regarding the inspection information with all the data and the photographs.
When Must you Inspect a lightning Rod?
According to industry standards, you must conduct an inspection when
- Firstly, when a building undergoes a repair or modification
- Secondly, during the initial installation of the lightning protection system
- Thirdly, when a lightning bolt strikes a structure.
For this, you can install a lightning event counter that counts the number of times lightning strikes the structure. Even If any of the above situations do not arise, you must periodically inspect the lightning protection system.
The maintenance protocol suggests you do the following verifications regularly.
For protection I and II, you must do an annual revision. For protection levels III and IV, you can perform a visual verification after every two years.
For protection levels I and II, you must conduct complete verification after every two years. For protection levels III and IV, you can do it after every four years.
Complete verification of critical systems:
You must do this verification annually for all types of protection levels to prevent the damaging effects of lightning bolts.
Some countries have high rates of precipitation during the rainy season. In such countries, you must inspect before the beginning of the rainy season. You can call a specialist for lightning protection installation. The person will also do the inspection and maintenance. However, check if the concerned person has lightning protection professional certification.
Lightning protection systems intercept any lightning before it strikes a building. Thus, you must ensure that cables, wires, electrodes, and other components are always in good working condition. If you need any help regarding lightning rod installation, contact Cloom. We deal in a wide variety of cable assemblies and wiring harnesses.