Lightning protection: calculation, installation, verification, earthing

Every year, many buildings and electrical equipment suffer from the effects of lightning discharges. To protect buildings from such natural phenomena, a lightning protection system should be installed .

Lightning protection in a private house is a complex of measures and facilities that ensure the safe operation of a land facility during a thunderstorm period. This is a necessary attribute of any structure that provides protection of explosive, fire dangerous, technological, material values, as well as people from primary and secondary manifestations of lightning.

Features of choice

If there are no lightning protection devices on the structure, a lightning strike can cause a fire, destroy the object or damage a person.

The main device of the lightning rod is single, but different materials are used for the construction. When choosing this design, it is necessary to take into account such parameters:

- Features of the construction of the structure.

- Intensity of thunderstorms for a year in a certain area.

- Desired safety degree.

High-quality lightning protection

Calculation of lightning rod zones should occur based on information on the width, length and height of the building for which a protective structure will be built.

In addition, one should take into account the average annual number of lightning strikes in a certain area of the territory.

In the process of manufacturing the project, specialists independently calculate the protection zones of the structure. According to these data, lightning protection is built. The calculation is simple, for this you can use a lot of calculators that are on the network.

Designation of the structure and lightning rod

Thinking about the protection from lightning, you should make a lightning protection project.

Today there are three types of lightning rods, which differ from each other in design features and operational requirements.

The first category includes facilities that work with explosive chemicals and store them. In such rooms there are always mixtures of dust, vapors and gases with air. They pose a huge danger to human life.

The second category includes facilities in which explosive substances are stored in hermetically sealed metal containers. In such conditions, dangerous explosive mixtures that consist of vapors, gases and dust with air can only arise in an emergency situation. As a result of the explosion, the destruction will be partial.

The third category includes premises in which explosive mixtures can not form.

It should be remembered that installation of lightning protection systems preventing direct hits, secondary impacts and drift of high potentials is necessary for structures that belong to the first and second categories. Buildings belonging to the third category need to install a lightning rod, which prevents direct lightning strikes and high potentials.

Kinds

Let's look at the example of a multi-storey house lightning protection device. It can be either external or internal. Each has a special purpose. Both the first and second species are very important. They ensure the safety of not only your property, but also the health of your loved ones.

External lightning protection in a private house is quite simple. It consists of the following elements:

- A current collector.

- Lightning collector.

- Earthing switch.

The interception of lightning directly above the roof, and after the passage of a charge through a safe channel and its removal to the ground - this is lightning protection. Calculation of the necessary materials for the construction of the structure should be given in the design documentation. Each person can mount the device himself.

But the scheme of the internal lightning rod is much more complicated. This is a whole range of activities that allow the safety of electrical appliances and wiring throughout the house. It is better to entrust this work to specialists. After all, only they can correctly choose the necessary equipment for your home, which will help to protect the premises from damage.

Consider the functions of each element of an external lightning rod.

Current collector

A collector is a specific conductor that connects the earth electrode and the lightning receiver to each other. For its manufacture use galvanized or black steel rolled products with a diameter of more than 6 mm. This element is connected by means of a metal yoke with nuts and bolts by the method of welding with grounding. It must be laid in such a way that there is as little distance between the lightning detector and the dredge. The outer part of this element must be available. This eliminates the possibility of weakening the damage or pulling the current lead.

The metal elements of the structure (pipes, fire stairs , etc.) can also be a current collector. The main thing is to ensure reliable electrical contact between all elements of the lightning protection system.

Lightning collector

The lightning detector is designed to intercept an electric discharge. Its role can be performed by a metal mesh, rod or rope.

The metal lightning receiver in the form of a grid is installed directly on the roof of the building. For the manufacture of this element, rolled steel with a round section or strip of this material is used. If you decide to install a lightning receiver of this type, you should create conditions for the constant cleaning of ice or snow from the roof. Also you need to take care of unhindered drainage of precipitation. The liquid must never remain on this part of the structure. The maximum size of the cells is 5 x 5 m.

The lightning collector in the form of a metal rod is traditional for our country. It began to be used in the 18th century. Most often it is installed in private homes. Fix the rod on the roof. It is made of profile metal.

The lightning receiver in the form of a cable looks like a metal rope, which is suspended on supporting structures. Horizontal lightning rods are located on two grounded supports. Most often they are installed on technical facilities, which are characterized by a considerable extent (overhead power lines). This type is very rarely used to protect buildings from being hit by lightning.

Lightning protection facilities directly depends on this element of the system.

Earthing switch

It is a metallic conductor, which must necessarily contact the soil. Most often in the role of a ground plane are the products of rolled metal: angular profile, strip or pipe.

The manufacture of a lightning rod with its own hands allows the use of substandard or formerly used gas or water pipes. Remember that the earth electrode must be cleaned from corrosion. The most optimal option is the use of galvanizing. If there are people near the grounding conductor during a thunderstorm, its resistance should not exceed 10 ohms.

Project

Before proceeding to construction, a lightning protection project should be created. It is better to entrust this to specialists. The project should provide for the construction of a lightning conductor of the structure, taking into account its main purpose, that is, the category. For example, an apartment house is classified as Category III.

The project must include the following:

- Type of lightning receptacle (of what material is made, the step of the cells).

- Features of the current collector (from which it is made, the diameter of the wire, the method of attachment to the lightning receptacle, grounding).

- Features of grounding (location, depth of location, of what material is made).

Lightning conductor installation

You should select the highest point on the roof. Here you need to fix the mast, which will be installed lightning receiver. Its height causes arguments even among specialists. Some argue that high masts can catch lightning, which could bypass the house side. Others believe that the higher it is, the better will be lightning protection. Calculation of the height of the lightning detector does not lead, since this question is controversial. Therefore, experts do not indicate the exact length of the mast.

It is better to make a mast from a wooden beam. The lightning receptacle must be securely attached to the top of the mast. Most often, for these purposes, tightly clamped metal clamps are used.

A lightning conductor should be connected to the conductor. He is fastened to the mast with plastic bands. In the role of a conductor often use a cable that is easy to pass down the drain. So you can protect it from gusts of wind, ice and snow.

Lightning protection and grounding are closely related to each other. After all, the correct arrangement of the last element contributes to the safe removal of electric charge.

At a distance of 3 meters from the house should dig a hole. It is better to choose a place where people rarely walk and cars do not stand. The depth of the pit depends on the level of groundwater table. It is desirable to lay grounding rods in moistened ground. In the excavated pit, a grounding rod is laid, to which a current collector is attached. After the hole is carefully buried.