Main grounding bus: rules of use, how the GZSh should ground equipment and buildings

The operation of all kinds of electrical devices must be ensured by a safe connection method. To protect against short circuits and ground faults, all such devices must be connected to the protective grounding and neutralization complex. The main element of this system is the main ground bus, or GZSH.

Using a grounding structure

The grounding system of any object consists of a grounding loop, grounding wires of devices, grounding of control cabinets, assemblies and GZSh. The primary purpose of such a device is to create an isolated space with zero potential. This is done by means of several conductive parts.

The grounding bus is used in such cases:

• For equalizing currents in an electrical circuit.
• In communication facilities where metal pipes and other devices are laid. These are gas pipelines, heating mains, water supply systems.
• In the metal parts of buildings and structures.
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• In complexes of supply and exhaust ventilation.
• In lightning rods and lightning protection.
• As part of a complex of grounding devices.

According to the PUE, any grounding bus must withstand the connection of at least five live parts. Its cross-section must be greater than the cross-section of the wires connected to it. Installation should provide free access only for personnel serving this facility with the required electrical safety approval group.

General rules and stages of laying

All techniques and methods of organizing the grounding complex, as well as materials, dimensions, length of welds are described in the PUE. This system combines de-energized metal parts that are part of the design of electrical equipment. Installation takes place in the following sequence:

• First, the grounding structure is assembled.
• Then they are laid to the installation.
• In the last step, the grounding conductors are fixed to the bus.

Street circuit installation basics

The first is to place the contour in the ground. It is made from a metal pipe, fittings, a corner by welding. Do not paint the ground as this will reduce contact with the ground. Then a ditch about half a meter deep is pulled out from the place where the tire will enter the building.

The shape of the dug trench should be an isosceles triangle. Then, at a distance of about one and a half meters, with the help of a sledgehammer or any other devices, sharpened pins at a depth of at least 3.5 m. The produced welded strips are laid in a trench and welded to the posts. In the corner of the grounding entry into the wall, they form a closed system.

Indoor "earth"

After finishing the installation of the street part, the grounding system is laid inside the building. A steel strip with dimensions up to 8 mm in width and 3 mm in thickness is suitable for this. And also fittings with a cross section of 5.5 sq. mm. You can use finished products that are sold in special organizations.

The rules for installing grounding in a building are as follows:

1. The distance to the ground or floor from the contour is at least 40-60 mm to prevent rust.
2. The strip can be attached to the wall using dowels or wedges by welding.
3. All passages inside are made in protective covers.
4. The joints are welded as follows: if the contour is flat, the length of the seam is not less than its width, the round contour is welded with a seam with a length equal to six of its diameters.
5. If the circuit runs at a height, it should rest on metal racks driven into the ground in the same way as street pins.
6. Recommended painting in black. Any other is marked with purple stripes every 1.5 meters.

Grounding device in shields

The installation of the GZSh is completed at the points of direct connection of the grounding conductors. This can be a separate cabinet or directly from control or assembly boards. Grounding in control cabinets. The installation of the grounding bus and its connection to the circuit is mandatory.

Earthing devices with PE marking are usually installed in shields.

The cross-section of the conductor must be of a certain cross-section:

• Copper - 1.1 sq. cm.
• Aluminum - 1.7 sq. cm.
• Steel - 1 sq. cm.

The grounding strip itself must be suitable for the dimensions of these wires. Usually, a protective neutral is installed in the control cabinets. By installing these two tires, maximum safety is achieved when working with such installations.

Copper is a low resistance material. In a standard installation, the strip is attached to special brackets that are directly connected to the body. It handles thermal loads and short-circuit currents.

The most common copper ground bus is made from copper strip. Electrical copper corresponds in quality to the M-1 grade and GOST 434−78. This grade contains 99 percent pure copper, which is why such a tire is used in the temperature range from minus 55 to plus 380 degrees. The highest voltage under these conditions is 1,000. volt. All parameters are indicated on the marking: width, thickness, length.

Grounding made of such metal is also installed on the street. This is due to the following characteristics:

• High level of thermal conductivity.
• High level of electrical conductivity.
• Low resistance.
• Does not rust.

Such a bus is often installed as lightning rods.

Completion of work

After completing the installation of all branches, it is necessary to visually and by tapping check the correctness and reliability of all connections. The bolted connections must be pulled again. After that, it is necessary to measure all the resistances and enter them in the measurement log. If all the data meet the requirements, the trench on the street can be sprinkled.

A correct and reliable grounding system ensures the safety and correct operation of all electrical equipment. That is why it is better to entrust such assembly operations to specialists.

Commissioning of grounding must be carried out by organizations that are authorized for testing and by qualified personnel.