The LED display screen itself is a large-scale engineering project, ranging from a few square meters indoors to several hundred square meters, while the area of LED outdoor display screens ranges from tens of square meters to thousands of square meters. Because LED screens are known as "electric tigers", the larger the screen, the greater the power, and corresponding distribution cabinets need to be equipped. And LED outdoor display screens also need to consider measures such as lightning protection and grounding. So, how can the grounding of LED electronic screens be considered safe? Below is a brief analysis by the manufacturer of Huaxintong Optoelectronics LED display screens.
How to consider grounding of LED electronic screens safe
In the early days, due to the low threshold of the high-definition LED display industry, a large number of personnel with uneven technical skills flooded in. Although major LED display manufacturers have opened channels across the country to improve their service systems and expand their operations, due to differences in technology among these channels, they are not particularly familiar with certain professional technologies. For example, regarding the grounding issue of LED electronic large screens, some customers believe that the lower end of the LED outdoor display column structure is connected to the ground, so there is no need to perform display grounding work. However, some customers believe that since the power supply is installed inside the box and the boxes are connected to each other with locks and structures, only structural grounding is done without power grounding.
In fact, these two methods are wrong. The column is connected to the foundation's anchor bolts, which are embedded in concrete. The resistance of the concrete is in the range of 100-500 Ω. If the grounding resistance is too high, it will lead to delayed leakage current discharge or residual. To prevent rusting of the outdoor high-definition LED display box, LED display manufacturers generally use a box that has been sprayed with paint when purchasing the box. However, the paint itself will affect conductivity, resulting in poor contact or increased grounding resistance of the box connection, and even the possibility of electric sparks interfering with the screen signal.
If only structural grounding is done without screen grounding, oxidation and corrosion will occur on the surface of the box or structure over time, and screws and other fixing parts will gradually loosen due to thermal expansion and contraction caused by temperature differences, resulting in weakened structural grounding effect and even grounding failure, posing a certain safety hazard to the screen. There is a possibility of safety accidents such as screen leakage and chip interference damage.
Below, Huaxintong Optoelectronics LED display manufacturer will briefly introduce the correct grounding method for LED electronic large screens. Generally speaking, the power input terminal has three wiring terminals, namely the live wire, neutral wire, and ground terminal. The correct grounding method is to use a dedicated yellow green dual color wire for grounding to string and lock all power grounding terminals, and then lead them out to connect to the grounding terminal. If there is no grounding terminal on the installation site, it can be connected to a pipeline buried in and in good contact with the ground, such as an iron water pipe or iron sewer pipe. To ensure good contact, a wiring terminal should be welded on such a natural grounding body, and then the ground wire should be tightly locked on the wiring terminal without binding or connecting. However, flammable and explosive pipelines such as gas shall not be used. Or bury grounding bodies on site. The grounding body can be made of angle steel or steel pipe, which can be buried horizontally or vertically in the ground as a simple grounding point. The grounding point should be selected in a remote place to prevent pedestrians or vehicles from damaging the grounding body.
In addition, the grounding resistance during grounding must be less than 4 Ω to ensure timely discharge of leakage current. In addition, it should be noted that the lightning protection grounding terminal needs a certain amount of time to discharge lightning current due to the diffusion of ground current, which can cause the ground potential to rise in a short period of time. If the grounding of the LED display screen is connected to the lightning protection grounding terminal, the ground potential will be higher than that of the display screen, and the lightning current will be transmitted along this ground wire to the screen body, causing equipment damage. Therefore, the protective grounding of LED display screens must not be connected to the lightning protection grounding terminal, and the protective grounding terminal must be at least 20 meters away from the lightning protection grounding terminal. Prevent the counterattack of ground potential.
Summary of LED grounding precautions:
1. Each power supply must be grounded from the grounding terminal and locked securely;
2. The grounding resistance shall not exceed 4 Ω;
3. The ground wire should be a dedicated conductor and must not be connected to the neutral wire;
4. No circuit breakers or fuses shall be installed on the ground wire;
5. The ground wire and grounding terminal should be kept at least 20 meters away from the lightning protection grounding terminal;
