Long ago, it was believed that lightning was a punishment for sins, and that a stork on the roof could protect a house from being struck by lightning. Today, it is known that humans have no influence on electrostatic discharge and other natural phenomena. However, they can effectively prevent the effects of their occurrence. A lightning protection system, also known as a lightning rod, protects buildings from fire and other consequences of lightning strikes. Is the installation of a lightning rod mandatory? How does a lightning rod work? What elements does it consist of? And how much does it cost to install a lightning protection system? Onninen experts answer these and other questions about lightning rods.
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When is a lightning rod mandatory?
Lightning strikes are one of the main causes of building fires. A lightning rod protects the house, installations, electrical devices and household members from the often tragic effects of lightning strikes. The obligation to equip a given building with a lightning protection system results from legal regulations. According to § 53 section 2 of the Regulation of the Minister of Infrastructure of 12 April 2002 on the technical requirements that buildings and their location should meet (Journal of Laws 2002 No. 75 item 690 with subsequent amendments): "The building should be equipped with an installation protecting against atmospheric discharges. This obligation applies to buildings specified in the Polish Standard on lightning protection of buildings."
This is the PN-EN 62305 standard, which introduces a system for assessing the need for lightning protection. This is one of the exceptions where the application of the standard is mandatory. The risk (R) of loss of human life or permanent electric shock, loss of public services and loss of cultural heritage is subject to calculation. Based on the obtained risk value, appropriate measures should be selected so as not to exceed the acceptable tolerable risk (RT). The PN-EN 62305 standard contains not only a detailed description and calculation methodology, but also regulates materials and shapes and minimum, permissible transverse dimensions of external lightning protection system elements in buildings (air terminals, down conductors and earthing).
It also contains the principles of laying air terminals and the conditions for using the roof covering of a building. To facilitate the analysis, calculation examples are provided for various types of buildings, e.g. a house, a block of flats, a hospital, etc. In practice, an investor building a house will rarely consider a lightning protection system, leaving the decision in this respect to the designer. Moreover, according to the provisions of the PN-EN 62305 standard, the designer may decide whether to implement lightning protection or not, regardless of the calculation results, based on his own experience and knowledge. If you are going to build a house or reconstruct the roof, be sure to consult a designer. Do you design, install or service lightning protection systems? Treat the PN-EN 62305 standard as required reading.
It is worth remembering that having a lightning protection system may be required by your insurer. If you have a home insurance policy that covers the risk of lightning strikes, be sure to check the insurer's liability conditions in the general insurance conditions. This document often includes a provision that the building must be equipped with a properly functioning and regularly inspected lightning rod.
The role of lightning protection in building safety
When the potential difference increases sufficiently, an electrical discharge can begin. The task of a lightning protection system is to intercept the atmospheric discharge that has been directed at a given building and to conduct the lightning current below the ground surface. Below the ground surface, the current is dispersed thanks to the grounding system. This is the principle of operation of a lightning rod in brief.
Lightning protection plays a key role in building safety, as it protects not only the building, installations and equipment, but above all human life. A lightning strike to the roof can cause a fire, damage an electronic device and, in extreme cases, electrocution.
In the case of most standard single-family homes, the use of a lightning rod is NOT mandatory, which does not change the fact that it is worth having solid lightning protection. You will gain peace during lightning discharges.
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Elements of lightning protection installation
The lightning protection system is not just a metal rod visible on roofs, but a whole system of elements running along the surface of walls and located in the ground. A traditional lightning rod is constructed:
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from air terminals – air terminals are wires made of stainless or galvanized steel that connect the lightning arrester to the ground, receive the discharge (lightning strikes the air terminal) and discharge the current to the ground, they must be connected to other metal elements of the roof, e.g. antennas; - from down conductors and grounding conductors – the down conductor is used to connect the air terminal and the grounding conductor or earth electrode in the foundations, and the grounding conductor connects the down conductor to the earth electrode;
- from the grounding electrode – the grounding electrode is a metal element of various structures, located below the ground surface, constituting the end of the lightning protection installation, made of electrically conductive materials;
- from test connectors – a special clamp that connects the down conductor to the grounding conductor, mounted above the ground.
What is an active lightning rod?
The active lightning rod is a solution that has been heavily promoted in recent years. It has a mast and a special head with an ionizing device mounted on it, which uses the surrounding electromagnetic field to increase the electric potential on the blade. A positive feedback system stimulates growth. As a result, the action of the bottom-up precursor is initiated. The discharges are discharged into the ground through a single air terminal with a pin grounding. The active lightning rod is supposed to protect a larger area than a traditional lightning protection system, but expert opinions on this subject are divided.
Lightning protection installation costs
The cost of installing a lightning protection system is influenced by various factors. Prices start at around PLN 2,000, but can exceed PLN 10,000. The final cost will depend primarily on the building's square footage, size, shape and roof material, type of lightning protection wire, quality of equipment, number of earthings, method of routing lightning protection wires, as well as the location, pricing policy and reputation of the selected contractor. As a rule, you will pay more for a lightning protection system with an active system. It is worth asking several installation companies in the area to send you an individual offer. Do not be guided only by price. Treat this expense as a long-term investment in the safety of household members and electronic equipment. It is best to plan lightning protection at the building design stage.
Lightning rods at the Onninen wholesaler
In the Onninen electrical installation wholesaler you will find the highest quality lightning protection equipment. Our offer includes masts, spikes, air terminals and accessories, lightning protection earthing rods, vertical and horizontal air terminal elements, solutions for creating grounding and equipotential connections, lightning protection pipes with accessories, strips and lightning protection wires.
Don't know which lightning protection wire or other lightning protection element to choose? Onninen experts provide professional support in selecting solutions. Contact us!