Lightning conductor with own hands

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Arrangement of the lightning rod in the country site is an important condition for the safety of being on it during a bad weather. Discharges of an electric current of enormous power in the presence of a lightning rod do not affect the design of the house and other elements that are in the protection zone. However, you should not think that the lightning rod prevents lightning strikes. Everything is different. It becomes a conductor for discharging the discharge from the house, leading a current of up to 100,000 amperes into the earth electrode.

Lightning device options

A classic lightning rod can be made in one of two variants: in the form of a single rod or a system of cables stretched between the lightning receptacles. The first option is usually used to protect an individual house, while the second is used to create a safe zone on a whole site. A cable lightning rod is also recommended for buildings that are of considerable length.

lightning rod

Components of the lightning rod

Lightning protection in the first place needs homes with a roof made of metal or metal, as these options do not have a ground, so during a lightning they accumulate electric charges.

In the case of a metal roof without an insulation layer having a coating thickness of 4 mm for iron, 5 mm for copper, or 7 mm for aluminum, a simplified lightning conductor device is possible when the lightning collector takes over the surface. In this case, every 20 meters of the roof is grounded. Here you need to take into account the quality of the roof, because if there are any gaps, then the desired effect from such a lightning detector will not be.

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

  • lightning detector( 1) in the form of a thin electrode or a system of electrodes placed above the house at a certain height;
  • current lead( 2) - the cable connecting the receiver to ground;
  • of the earthing switch( 3), which leads to ground current.

lightning rod

Lightning collector

An element in which a lightning strikes a lightning rod is a lightning detector. It is usually performed in the form of a rod made of steel, copper or other material with similar conductivity. Do not cover it with paint or varnish to avoid corrosion, otherwise it will lose the desired properties.

Cross-sectional area: for steel - 50 sq. M.mm, for copper - 35 square meters.mm, for aluminum - 70 square meters.mm.

You can install lightning receivers from different sides or the center of the roof. If several lightning detectors are installed, they are connected to a common circuit, which is closed to the earthing switch. The rod can be located not only on the roof surface, but also on the chimney or the nearest tall tree. Optimal height is not more than 15 meters. If it is installed on a tree, the fastening is done so that the rod rises above the crown by at least 0.5 m and 10-15 cm above the house.

In addition to fire extinguishers, there are also possible options for a protective mesh( reinforcement 6 mm thick) and a cable system. The second method is more rational for a holiday home, as the cable stretches above the roof level, and the grid is placed on the roof itself. A cable with a diameter of at least 5 mm is pulled over the roof ridge on the posts, then lowered downwards, where it is connected to the earthing switch. Thus, it performs both the function of a lightning collector and a current collector.

lightning rod

Also as the receivers can be used separate parts of the structure( drainpipes, metal fences).Their use is allowed if they have a cross section greater than necessary for normal protection.

Current collector

The current collector is designed to connect the lightning receptacle and the earth conductor. It is made of aluminum or copper wire of large cross section. For these purposes, a twisted wire is suitable, which is used for laying overhead power lines. The current lead is clamped using terminal blocks, couplings or crimp pipes.

Current collector

The distance between the lightning arrestor and the earthing switch must be kept to a minimum, so the wire is directed straight down. The number of current leads depends on the area of ​​the house. For cottages with an area of ​​about 200 square meters.m it is recommended to install 2 current collectors at a distance of about 20 m from each other.

It is fixed on a special pole or directly on the wall of the house using plastic fasteners. To protect the current collector, it can be isolated from the environment through a cable duct.

Earthing switch

Since the earthing switch is needed for discharging a lightning bolt into the ground, it must have a small electrical resistance. For these purposes, expensive materials such as copper, aluminum, brass and other stainless metals, and cheaper ordinary steel are suitable. The earthing device should not have any damage and traces of rust, as they can cause a reduction in the diameter of the rods due to the destruction of the metal.

For qualitative grounding, not one but several rods can be used that are immersed in the ground away from the tracks and roof, especially if it is made of flammable material. In summer conditions, any large metal object that is available at hand: a back from an old bed, a cast iron bathtub, a reinforcing mesh and the like, can also be used as a grounding electrode.

The type of grounding depends on the parameters of the house and the characteristics of the ground. Dry ground is characterized by a low level of groundwater. To reach the moist soil, vertical grounding is necessary. The earthing device in this case is made of two rods of 100 mm and 2-3 m in height, driven at a distance of 3-4 m from each other. The rods are connected by wire, cable( copper, aluminum) or tinned iron plates, to the center of which the current collector is welded.

The wet ground is characterized by a higher groundwater level, therefore it is possible not to make a vertical grounding by replacing the rods with corners of strip steel, water pipes or other similar metal elements. The horizontal earthing switch is laid to a depth of 1 m.

In this case, the earthing switch can also be operated by a current collector placed in the ground in such a way as to occupy the largest possible area of ​​contact with the soil. The joined structure can have the shape of a scallop( letter W) or a triangle. It is unacceptable for wire fastening to use manual twisting and pliers, only normal or cold welding is allowed.

Current collector

It is necessary to pay special attention to the placement of the earthing switch. This should be remote from the house and tracks a place inaccessible to children and pets, preferably fenced. The minimum distance to the house should be at least 1 m.

Since water is an excellent conductor of electric current, it is better if the soil around the earth electrode is wet, then the discharges will quickly escape into the ground without accumulating on the rod. Provide additional moisture can be through the flow of rainwater from the drain from the roof or a targeted irrigation of the soil.

Calculation of the protection zone

For each structure it is necessary to calculate the lightning rod, since each configuration is capable of providing a protective zone of various sizes. The parameters of this zone can be calculated independently, taking into account the features and dimensions of the country house.

A single rod forms a protective zone, which is close in geometry to a cone with an apex angle of about 45 °.The vertex of this cone will be at the highest point of the lightning rod. At the cable-type lightning detector, the protection zone has a more complex geometry, in which the cable serves as an edge, and each rod forms its cone.

The calculation of the protective zone of a single rod can be performed using the following formula:

R = 1,732 * h,

where R is the radius of the zone above the highest point of the house, h is the distance from the highest point of the house to the lightning rod peak.

Calculation of the protective zone

To find out if the pit height is sufficient to protect a certain zone at ground level, you can use the following calculation. Let's say that the height of the cone will be designated ho , the radius on the ground is Ro , the height of the building is hx , the radius at the building height is Rx , the height of the rod is h. Then, taking into account the height of the existing lightning rod and the height of the house, the unknown values ​​will be calculated using the formulas:

ho = 0.92 * h,

Ro = 1.5 * h,

Rx = 1.5 *( h-hx / 0.92).

In practice, the calculations look like this: if the rod has a length of 10 m, the radius of the protection zone on the ground will be 1.5 * 10 = 15 m, the remaining parameters are calculated in a similar way.

To calculate the required length of the rod, you can use the same formulas, substituting in them the desired radius of the protective zone. In the case of complex lightning detector geometry, you need to draw a graphic model of the house and lightning rod and calculate the protection zone geometrically.

The height of the lightning conductor should not exceed 12 m, so if it is not possible to meet these limitations using a single rod, several masts are recommended to extend the protection zone.

Installation of the lightning rod

To install the lightning conductor correctly, the following procedure should be followed:

  1. Measure the height of the roof and determine its geometry. For clarity, draw a diagram on which you can define the future protective zone.
  2. Determine the type of lightning detector. For square houses, a single rod is sufficient, for long structures, the use of a cable system is optimal.
  3. Calculate the protective zone and determine the desired height of the rod( s).The minimum cross-section of the lightning detector must be related to its height in the proportion of 5 sq. Km.mm per meter.
  4. Determine the point of attachment of the lightning receptacle and fix it to the roof or wall.
  5. Dig a pit for the earthing switch and place it at the desired depth.
  6. Connect the earthing switch and the lightning detector to each other.
  7. Check lightning rod with multimeter. Its resistance should not exceed 10 ohms.

Arrangement of the lightning rod on the

tree. It is possible to equip the lightning rod on a tree that is 2.5 times higher than the house and is located at a distance of not less than three meters from it. The lightning collector in this case is attached to a long metal pole fixed to the tree with the help of clamps made of a synthetic halyard. The connection to the earth electrode is carried out by a wire of at least 5 mm in cross section.

Placement of a lightning rod on a tree

Continued use of

The installed lightning rod does not need special care. It only needs to be checked periodically for damage and the quality of the metal connections. If the lightning rod of the receiver has decreased in diameter or the joints have lost integrity, then these elements need to be replaced. The location of the earthing switch should also be checked, and the ground around it should be kept moist.

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