Lightning rod with his hands

Construction of a lightning rod at their summer cottage - an important condition for the security of finding it during bad weather.Discharges of electric current of great strength in the presence of a lightning rod does not affect the design of the house and the other elements that are in the protection zone.But do not think that prevents lightning rod lightning strikes.Everything is different.He becomes a guide for the removal of the discharge from the house, taking a current of up to 100 thousand amperes in earthing.

Options lightning rod

devices Classic lightning conductor can be done in one of two ways: as a single rod or cable system strung between Lightning.The first option is typically used to protect an individual at home, while the second - to create a safe zone in the whole area.Rope lightning rod is also recommended for buildings of considerable length.

Components of a lightning rod

in protection from lightning in the first place need a house with a metal roof or metal, as these options do not have a ground, so during storms accumulate electrical charges on yourself.

In the case of a metal roof without the insulating layer having a coating thickness for the iron - 4 mm, for copper - 5 mm or aluminum - 7 mm, the lightning rod unit may simplified when air terminal part assumes its surface.In this case, every 20 meters, the roof is made grounded.Here it is necessary to take into account the quality of the roof, because if there are any gaps, the desired effect of such air terminal will not.

In other cases, a lightning rod should consist of the following elements:

• air terminal (1) in the form of a thin electrode or system of electrodes installed over the house at a certain height;
• collector (2) - the cable connecting the receiver to the ground;
• earthing (3) leading off the current in the ground.

Lightning

element in which the presence of lightning rod lightning strikes, a lightning arrester.It is usually performed in the form of a rod of steel, copper or other material of similar conductivity.You do not need to cover it with paint or lacquer to prevent corrosion, otherwise he will lose the desired properties.

sectional area: Steel - 50 square meters.mm, for copper - 35 square meters.mm, for aluminum - 70 square meters.mm.

Set Lightning can be from different sides or in the middle of the roof.If you install several air terminals, they are joined in a common circuit, closed on earthing.The rod can be positioned not only on the surface of the roof, but also at or near the chimney high tree.The optimum height of no more than 15 meters.If it is set on the tree, the fixation is made so that the rod crown towered over by at least 0.5 m and at 10-15 cm above the house.

rods addition variants are possible protective mesh (fitting 6 mm thick) and a rope system.The second method is more rational for a holiday home, as the rope is stretched at a height above the roof level, and the grid is placed on the roof itself.The cable is not less than 5 mm in diameter pull on the ridge of the roof on the racks, and then lowered down, which connect it to the grounding.Thus, it performs the function of the collector and the air terminal.

also in some parts of the structure can be used as receivers (gutters, metal fences).Their use is permitted if they have a cross section larger than necessary for normal protection.

The collector The collector is designed to connect the air terminal and grounding.Running he made of aluminum or copper wire of a large section.For this purpose, suitable twisted wire, which is used for routing of overhead power lines.Fixing is carried out using the collector terminals, couplings or crimp tubes.

distance between the lightning arrester and earthing should be minimal, so the wire is directed straight down.Number of shunts depends on the area of ​​the house.For cottage area of ​​about 200 square meters.m 2 is recommended to install a collector at a distance of about 20 m from each other.

is fixed it on a special pole or directly on the wall using a plastic fasteners.In order to protect the collector can isolate it from the environment by means of the cable channel.

Earthing

Since earthing is needed to divert the lightning into the ground, then he should have a small electrical resistance.For this purpose, suitable both expensive materials such as copper, aluminum, brass and other corrosion-resistant metals and cheaper ordinary steel.Earthing must not be damaged, and traces of rust, as they may cause a decrease in the diameter of the rods due to the destruction of the metal.

For quality grounding can be used not one but several rods, which are immersed in the soil away from the tracks and the roof, especially if it is made of flammable material.In summer conditions, as well as earthing can use any large metallic object, is available at your fingertips: the back of the old bed, cast iron bath, reinforcing mesh, and the like.

grounding type depends on home soil parameters and features.Dry soil has a low water table.To talk reached the moist soil, you need vertical ground.Earthing in this case, the cross section of the two rods 100 mm and 2.3 m in height, are driven at a distance of 3-4 meters from each other.The rods are joined together with wire, cable (copper, aluminum) or tinned iron plates, to which the center of the collector is welded.

to wet the soil characterized by a high water table, so you can not perform a vertical ground by replacing corners flat steel rods, water pipes or other similar metal elements.Earthing laid horizontal to a depth of 1 m.

In this case, the earthing part and the collector may carry, laid in the ground so as to occupy the largest possible area of ​​contact with soil.Associated structure may have the shape of scallop (letter W) or the triangle.It is unacceptable when fastening wires and the use of hand-twisting pliers may only be ordinary or cold welding.

Placement earthing should be given special attention.It should be deleted from home and tracks of the reach of children and pets, preferably fenced.The minimum distance to the house should be at least 1 m.

Since water is an excellent conductor of electricity, it is best if the soil around the earth electrode is wet, then the level will soon go into the ground and accumulate on the rod.To provide extra moisture, you can use the flow of rainwater runoff from roofs or targeted irrigation of the soil.

Calculation protection zone

For each structure is necessary to calculate the lightning rod, as each configuration is capable of providing a protective zone of different sizes.The parameters of this zone can be calculated independently, taking into account the characteristics and dimensions of the holiday home.

single rod forms a protective zone which is close to the geometry of the cone having a vertex angle of approximately 45 °.The top of the cone will be located at the highest point of a lightning rod.At the air terminal of the cable-type protection zone it has a more complex geometry, in which the cable is an edge, and each rod forms a cone.

Calculation of the protection zone of a single rod can be made using the following formula:

R = 1,732 * h,

where R - radius zone on the highest point of the house, h - the distance from the highest point of the house to the peak of a lightning rod.

To find out whether the rod height sufficient to protect a certain area on the ground level, you can use the following calculation.For example, the height of the cone is designated ho , the radius on the ground - Ro , building height - hx , the radius at the height of the building - Rx , stem height - h.Then, taking into account the height of the existing lightning rod, and the height of the house unknown values ​​will be calculated according to the formulas:

ho = 0,92 * h,

Ro = 1,5 * h,

Rx = 1,5 * (h-hx / 0, 92).

In practice, the calculations are as follows: if the rod has a length of 10 m, the radius protection zone on the ground will be 1.5 * 10 = 15 m, other parameters are computed similarly.

To calculate the required length of the rod, you can use the same formulas, substituting in them the desired radius protection zone.In the case of the air terminal complex geometry need to draw a graphical model of the house and the lightning protection zone and calculate geometric means.

lightning rod height should not exceed 12 m, so if you can not keep within these limits, using a single rod, it is recommended to use several masts to extend the protection zone.

Installing a lightning rod

To install a lightning rod was carried out correctly, it is necessary to adhere to the following procedure:

1. Measure the height of the roof, and to define its geometry.For clarity, draw a diagram on which you can determine the future protection zone.
2. determine the type of air terminal.For quite square houses a single rod for long structures optimally use a rope system.
3. Compute protection zone and determine the desired height of the rod (rod).Minimum cross-section of air terminal should be related to its high proportion of 5 square meters.mm per meter.
4. Determine the attachment point air terminal and fix it on the roof or wall.
5. dig a hole for grounding and place it at the desired depth.
6. interconnected earthing and lightning arrester.
7. Check lightning rod multimeter.Its resistance must not exceed 10 ohms.

Placing a lightning rod in the tree

To equip a lightning rod, and can be on the tree, which is 2.5 times higher than the house and is located at a distance of not less than three meters from him.Lightning in this case is attached to a long metal pole fixed to the tree using the clamps of synthetic halyard.The connection to the grounding wire is carried out not less than 5 mm in cross-section.

Further operation

installed a lightning rod does not need special care.It need only be checked periodically for damage and quality of the metal compounds.If the air terminal rod is reduced in diameter, or the joints lost their integrity, then require replacement of these elements.Place the earthing arrangement should also be checked, and the land around it maintained in the wet form.