Comprehensive guide for lightning protection of rural lighting electrical ready boards: the golden combination of grounding wire and surge arrester

The key to lightning protection in rural lighting electrical ready boards lies in the reasonable configuration of grounding wires and surge arresters. It is necessary to start from three aspects: the construction of grounding systems, the selection and installation of surge arresters, and supporting measures. The following are specific implementation points:

1、 Grounding system construction

Selection and installation of grounding body:

The grounding body should be composed of two or more steel pipes or angle steels, and several steel pipes or angle steels are commonly buried in a row or circle to improve reliability.

The grounding depth of the grounding body shall not be less than 2 meters, and the distance between each grounding body shall not be less than 2.5 meters. The distance between the grounding body and the building should not be less than 1.5 meters.

The grounding body should be made of hot-dip galvanized angle steel or flat iron to ensure corrosion resistance and conductivity.

Grounding grid welding:

Weld the grounding body with the structural columns, ground ring beams, and other steel bars of the building to form a reliable grounding network.

The welding joint should be firm, without virtual welding or leakage, ensuring good electrical connection.

Grounding wire laying:

The grounding wire must be a whole wire, and the connection with the grounding body must be made by electric welding or gas welding to ensure a firm connection.

The connection between electrical equipment and grounding devices can be made using screws, clamps, rivets, etc., but the connection must be reliable.

The grounding wire should avoid bending and choose the shortest path to connect to the grounding body to reduce resistance.

Grounding resistance test:

After the installation of the grounding device, a "grounding resistance tester" should be used to measure whether its grounding resistance meets the requirements (generally not greater than 10 Ω).

If the grounding resistance value is too high, additional grounding bodies should be installed or other resistance reduction measures should be taken.

2、 Selection and installation of surge arrester

Selection of surge arrester:

Select the appropriate type of surge arrester based on the voltage level and lightning protection requirements of the electrical ready board, such as valve type surge arrester, zinc oxide surge arrester, etc.

The surge arrester should have sufficient current carrying capacity and residual voltage level to ensure effective protection of the electrical ready board during lightning strikes.

Installation of surge arrester:

The surge arrester should be installed at the incoming end of the electrical ready board, near the main switch, in order to introduce the lightning current into the ground as soon as possible during lightning strikes.

The surge arrester should be installed vertically, firmly fixed, arranged neatly, and the distance between phases should not be less than the specified value.

The leads of surge arresters should be short and straight, and the contacts should have good contact to reduce resistance and inductance.

3、 Supporting measures and maintenance

Equipotential connection:

Local equipotential boxes should be installed inside buildings, especially in damp areas such as bathrooms. The grounding wires of related equipment should be welded together with the grounding grid to reduce safety hazards caused by potential differences.

Safe distance:

When grounding is introduced into the electrical ready board, it should be ensured that the underground grounding point is far away from the grounding point of the lightning rod to prevent damage to the electrical ready board caused by excessive current during lightning strikes.

Regular inspection and maintenance:

Regularly check the connection of the grounding system to ensure that there is no looseness, corrosion, or other issues.

Regularly test the grounding resistance to ensure it meets the specified value.

Regularly inspect the appearance and performance of surge arresters, and replace them promptly if they are damaged or aged.