Several grounding forms of computer room   There are basically four grounding forms in the computer room, namely: computer-specific DC logic ground, AC working ground, safety protection ground, and lightning protection ground.   1. Computer room grounding system Install a copper grid under the raised floor of the computer room, and connect the non-energized shells of all computer systems in the computer room to the copper grid and then lead to the ground. The grounding system of the computer room adopts a special grounding system, and the special grounding system is provided by the building, and the grounding resistance is less than or equal to 1Ω.   2. Specific practices for equipotential grounding in the computer room: Use 3mm × 30mm copper tapes to cross and form a square under the raised floor of the equipment room. The intersections are staggered with the positions supported by the raised floor. The intersections are crimped together and fixed with pad insulators under the copper tapes. The distance of 400mm from the wall in the computer room is to use 3mm×30mm copper strips along the wall to form an M-type or S-type ground grid. The connection between the copper strips is crimped with a 10mm screw and then welded with copper, and then lead down through a 35mm2 copper cable. The line is connected to the joint grounding body of the building, thus forming a Faraday cage grounding system, and ensuring that the grounding resistance is not greater than 1Ω.   Equipotential connection of equipment room: Make equipotential connection for ceiling keel, wall keel, raised floor bracket, pipes of non-computer system, metal doors, windows, etc., and connect multiple points to the equipment room grounding through 16m m2 ground wire. Copper grid.   3. Exchange work place The grounding required for operation in the power system (the neutral point of the power distribution cabinet is grounded) should not be greater than 4 ohms. The neutral line connected to the neutral point of the transformer or generator directly grounded is called the neutral line; the electrical connection of one or more points on the neutral line to the ground again is called repeated grounding. The AC working ground is the neutral point that is reliably grounded. When the neutral point is not grounded, if one phase touches the ground and a person touches the other phase, the contact voltage on the human body will exceed the phase voltage, and when the neutral point is grounded, and the grounding resistance of the neutral point is very small, then The voltage applied to the human body is equivalent to the phase voltage; at the same time, if the neutral point is not grounded, the grounding current is very small due to the large stray impedance between the neutral point and the ground; the corresponding protection equipment cannot cut off the power supply quickly, causing damage to people and equipment. cause harm; otherwise.   4. Safe place The safety protection ground refers to a good grounding between the casings of all machinery and equipment in the computer room and the body (casing) of auxiliary equipment such as motors and air conditioners and the ground, which should not be greater than 4 ohms. When the insulators of various electrical equipment in the equipment room are damaged, it will pose a threat to the safety of the equipment and operators and maintenance personnel. Therefore, the casing of the equipment should be reliably grounded.     5. Lightning protection ground That is, the grounding of the lightning protection system in the computer room is generally buried underground with horizontal connection lines and vertical grounding piles, mainly to lead the lightning current from the lightning receiving device to the grounding device, which should not be greater than 10 ohms. The lightning protection device can be divided into three basic parts: the air-termination device, the down-conductor and the grounding device. The air-termination device is the metal conductor that receives the lightning current. In this solution, only the down-conductor of the lightning arrester is connected to the grounding copper bar in the power distribution cabinet. The grounding resistance is required to be less than or equal to 4Ω.

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Post time: Aug-05-2022