Pay attention to the following matters when setting up lightning protection devices:
1. The grounding device should be designed according to the grounding resistance limit, soil humidity and conductivity characteristics, etc., the grounding method and location selection grounding and grounding wire layout, material selection, connection method, production and installation requirements, etc. Make specific provisions. After installation, use a resistance meter to determine whether it meets the requirements.
2. The location of the grounding wire should be chosen in a place that is not easy for people to go to, to avoid and reduce the harm of step voltage and prevent the grounding wire from being mechanically damaged. The grounding electrode should be kept at a distance of 3 meters or more from other metals or cables.
3. When the service life of the grounding device is more than 6 months, it is not advisable to use bare aluminum wire as a grounding electrode or grounding wire underground. In strong corrosive soils, galvanized or copper-plated grounding electrodes should be used.
How to set up a lightning protection device:
1. Air-termination devices are lightning rods, which can be made of galvanized pipes with a diameter of 25-32 mm and a wall thickness of not less than 3 mm or galvanized steel bars with a diameter of not less than 12 mm. They are installed on the scaffolding poles at the four corners of the house, and the height is not less than 1 meter, and all the horizontal poles on the top layer should be connected to form a lightning protection network. When installing the lightning rod on the vertical transport frame, the middle pole on one side should be connected to the top not less than 2 meters above the top. A grounding wire should be set at the lower end of the pole, and the hoist casing should be grounded.
2. The grounding wire should be made of steel as much as possible. The vertical grounding electrode can be a steel pipe with a length of 1.5 to 2 meters, a diameter of 25 to 30 mm, and a wall thickness of not less than 2.5 mm, round steel with a diameter of not less than 20 mm or 50*5 angle steel. The horizontal grounding electrode can be round steel with a length of not less than 3 meters and a diameter of 8-14 mm or a flat steel with a thickness of not less than 4 mm and a width of 25-40 mm. Also, metal pipes, metal piles, drill pipes, water suction pipes, and metal structures that are reliably connected to the ground can be used as grounding electrodes. The grounding electrode is buried in the highest point of the ground and is not less than 50 cm below the ground. When burying, the new fill should be rammed. In the often heated soil near the steam pipe or chimney duct, the masonry located above the groundwater level Grounding wires shall not be buried in coke slag or sand, and particularly dry soil layers.
3. The grounding wire is the down-conductor, which can be an aluminum wire with a cross-section of not less than 16 square millimeters or a copper wire with a cross-section of not less than 12 square millimeters. To save non-ferrous metals, round steel with a diameter of not less than 8 mm or flat steel with a thickness of not less than 4 mm can be used on the premise of reliable connection. The connection between the ground wire and the ground electrode is best to use welding, and the length of the welding point should be more than 6 times the diameter of the ground wire or more than 2 times the width of the flat steel. If connected by bolts, the contact surface shall not be less than 4 times the cross-sectional area of the grounding wire, and the diameter of the splicing bolt shall not be less than 9 mm. The above is just what we have accumulated in our work experience. It is more than that. I believe that the wisdom of the Chinese is infinite.
Post time: Dec-10-2020