Common problems in installing lightning protection equipment
Common problems when installing lightning protection equipment 1. The grounding resistance is too large or there is no grounding. The 'Video Security Monitoring System Engineering Design Specification' and 'Building Information System Lightning Protection Technical Specifications' do not clearly stipulate the grounding resistance of the monitoring system for lightning protection. Generally, the grounding resistance of the monitoring system is designed according to the resistance of the computer room and the grounding resistance of the information system: the independent grounding is not more than 4 ohms, and the combined grounding resistance is not more than 1 ohm. Specifically speaking, the grounding resistance of the monitoring system can be appropriately increased for different geological conditions. For example: forest fire prevention unit, the camera must be installed on the ridge, the address is bluestone, there is no river ditches within 200 meters, and no excavation is possible. Large gravel, soil zone. At this time, if the grounding of the monitoring system in this particular place is required to be no more than 4 ohms, and the cost is ten times or even dozens of times that of the monitoring system itself, then choose an appropriate increase in grounding resistance and use a cable with a large flow rate as the connection. Ground wire. 2. There is no direct lightning protection measures. This situation is more common with box cameras. Some people think that the three-in-one signal arrester has been installed and the grounding has been done. There should be no problem, but they don’t know that the arrester is lightning-proof conduction. Tools for thunder and induction thunder have no effect on direct lightning strikes. There are generally several methods for damage to electronic information systems by lightning: (1) Mechanical effects, such as lightning strikes on large trees, sometimes breaking the poles of large trees, mainly relying on the mechanical effects of lightning strikes. (2) Thermal effect, the instantaneous temperature of the lightning strike point can reach more than 3000 degrees, making the metal instantaneous. (3) Electromagnetic effect, this is an invisible killer, it uses electromagnetic induction to generate instantaneous strong current to burn out the equipment. Direct lightning protection only needs to rely on the lightning rod, which changes the direction of lightning and makes it unlikely that the lightning will directly hit the monitor. There is also a situation that makes the use of a curved ball machine install a lightning rod. In this case, the metal rod itself has protected the ball machine, and there is no need to increase the cost and install the lightning rod. 3. The signal arrester is too far away from the equipment to be protected. If the lightning arrester is installed too far away from the equipment, there is no way to eliminate the lightning current induced on the communication line and power line between the lightning arrester and the front end of the equipment. Therefore, it is recommended that the signal arrester should be installed directly at the front end of the monitoring equipment, especially where the signal power line is obviously routed. 4. The problem of grounding cables In order to save costs, metal rods are often used as the down conductors of the working grounding system, regardless of 'right' or 'no' for the time being. According to the design, the metal pole is generally used as the direct lightning protection system to lead down the wire. At this time, connect the working ground to the metal pole. If there is a direct lightning strike, there is no voltage difference between the front end of the signal arrester and the metal pole body. Direct lightning strikes will directly impact the signal arrester or power arrester, which will cause the arrester to age in advance or be damaged on the spot. Therefore, it is recommended that the work ground lead should be connected separately. 5. The choice of three-in-one surge protector (or BNC surge protector) According to the specific market conditions and time installation experience, the BNC signal electrophoresis protector is set within the range of lightning protection for a long time. This matter The protection of the monitor is far from enough. For the monitor, there are also surges, spikes, and burrs that affect it. The surge, spikes, and burrs may be the start of large nearby electric tools. Or turn off, and the changes in the nearby electromagnetic field, etc. These not only need the protection of pressure sensitive or discharge tubes, but also a logic filter circuit to provide a safer power environment for the monitor. As the latter factor is ignored. Lightning protection is a more complicated issue. The lightning protection design of the security monitoring system not only depends on the performance of the lightning protection device, but more importantly, before the design and construction of the monitoring system, it is necessary to consider the geographic location of the monitoring system. Environment, design appropriate cable routing, shielding and grounding methods. In short, the lightning protection design should be considered comprehensively in order to obtain good results. Chengdu Surveillance Installation Company--Chengdu Ruiminle Technology Co., Ltd. is a company that integrates Sichuan and Chengdu surveillance system installation and maintenance, monitoring equipment, camera camera installation, home security monitoring, access control systems, weak current engineering, integrated wiring, video surveillance, alarm systems, and anti-theft A multi-faceted technical service company integrating systems and smart homes, to provide you with satisfactory solutions. Welcome to inquire!