ESD anti-static grounding engineering construction plan and specification requirements
The national standard is less than 4 ohms, and the American standard is less than 1 ohm
静电ESD参考依据:EIA-625,MIL-263B,ESD ADV 3.0
温湿度MSD参考依据：IPC J-STD-001和IPC J-STD-033
1. Embedding of anti-static ground wire:
(1). The lightning rod of the plant building is generally welded together with the reinforced concrete of the building to properly ground, when the lightning strikes, the grounding point and even the ground of the entire building will become the discharge point of high voltage and high current, it is generally believed that there will be a "step voltage" within the range of 20M at the discharge grounding point, that is, it is no longer the ideal zero potential in this range. In addition, the neutral line of the three-phase power supply cannot be absolutely balanced, and there will be an unbalanced current that generates and flows into the grounding point of the neutral line, so the buried point of the anti-static ground wire should be 10M away from the building and equipment.
(2). Burial method: in order to ensure the reliability of grounding, there should be more than three points of grounding, that is, every 3-5m dig a pit of more than 0.5m, and drive more than 2m of copper-clad steel vertical direct pole (see Figure 1) into the pit (copper-clad steel is a new type of composite material, the material is a steel core inside, and the outside is copper, and has good conductivity (skin effect) of pure copper grounding material, corrosion resistance and hardness, tensile force and toughness of steel material, and has the advantages of lower cost than pure copper grounding material). The resistance reduction module (see Figure 2) has been added between the vertical and earth poles to achieve full contact with the ground, and then the three places are welded together with 70 square meters of stranded wire (see Figure 3), and the 16 square meters insulated copper core wire is welded into the room as the trunk line.
(3). Apply an appropriate amount of resistance reducing agent in the pit to increase the soil conductivity, and measure it with a grounding resistance tester (see Figure 4) after landfilling, and the grounding resistance should be < 4Ω and tested at least once a year.
2. Laying and testing of anti-static ground wire:
(1). The anti-static ground wire is all used 6m㎡ multi-strand copper core insulated wire, and each floor or appropriate section is connected with a copper bar or a switch of more than 40A, and the gate knife is connected to the main line to facilitate inspection and maintenance.
(2). The anti-static ground cable should be well insulated from the equipment shell, workbench iron frame, work lamp stand, etc., to prevent short circuit, lap connection or broken skin connection.
(3). At the "trunk end" of the segmented copper bar or switch, another inspection line is laid. (1.5~2m㎡), 2~3 checkpoints are set up in each workshop, fixed and clearly marked.
(4). Measurement: use pointer multimeter, resistance file.
a). The resistance between the anti-static test point and the anti-static ground wire is 5~15Ω, and the ideal should be 0Ω.
b). The resistance between the anti-static ground and the ground of the equipment, the resistance value is composed of the line resistance of the anti-static ground wire itself + the line resistance of the ground wire itself + the ground resistance between the two wires. However, due to the degree of dryness and wetness of the ground between the two grounding wires, the influence of ground current is very complex, especially the ground current, the frequency of the size direction is changing at every moment, and the measurement result is mainly determined, so it can only be measured with a pointer meter, and its value is normal from more than ten ohms to hundreds of K, which only shows that there is no short circuit between the two places and no open circuit.
On-site construction drawings:
Basic requirements for electrostatic grounding installation
1. 3m×φ20mm copper-clad rod for electrostatic grounding electrode.
2. The vertical burial depth of the electrostatic grounding electrode shall not be lower than 3m on the ground surface; Quantity and arrangement: no less than three, spacing 3-5 meters, in a "one" arrangement, filled with resistance reducing agent around the surface, the surface layer is covered with 0.5 meters thick backfill protective layer.
3. Grounding trunk material selection: 70 square copper-clad steel flexible wire; Connection: brazing together, and then soldering with 16m㎡ insulated multi-strand copper core wire and introducing it into the room as the trunk line;
4. After the electrostatic grounding is installed, it must be tested, and the grounding resistance value should be <4Ω;
5. After the electrostatic grounding electrode lead wire is wrapped in the PVC pipe and led to the room nearby, the end is riveted with copper terminals, and then fixed to the special electrostatic wiring cabinet with copper bolts for indoor anti-static trunk wire. Finally, it is measured with a ground resistance tester, and the ground resistance should be < 6Ω;
6. The electrostatic grounding electrode and the lead wire must be connected by welding or crimping;
7. Materials or parts used for electrostatic grounding shall not be painted before installation. Conductive contact surfaces must be deoxidized and tightly connected.
8. The contact resistance value of all connection points of the electrostatic grounding wire shall not be higher than 0.03Ω;
Introduction of copper-clad steel:
Copper-plated grounding rod is used in grounding devices, first originated in the United States, copper-plated steel-plated grounding rod is to use special electroforming technology to evenly cover 99.9% of pure copper on the low-carbon steel core, so that the copper and the steel core are completely molecularly combined, because of its good conductivity, strong corrosion resistance, high tensile strength, low price and other advantages have been widely used, and have been recognized by the American Institute of Electrical and Electronics Engineering (IEEE) standards, the British BS standard and the International Electrotechnical Commission IEC standards. In the eighties of the last century, it entered the mainland and was successively recognized by Sinopec, PetroChina, State Power and other companies, and was gradually popularized and used.
In recent years, the number of accidents caused by the failure of the grounding device in the petrochemical, electric power, communication and other system enterprises in the mainland has been increasing, and the reliability, stability and service life of the grounding device have been widely valued.
1. Factory ESD/EOS tubes
The production standard of electrostatic ground piles in the factory area
Grounding Standards:
1. There are 7 copper rods grounded and 11 electrostatic grounded with a length of 2.5M.
2. Buried in the ground depth of 5.5M, 40*40 galvanized angle steel connection, 6mm single multi-core wire connection
3. Chemicals are put in to increase its conductivity, and the cable is protected by PVC pipes.
4. Use the grounding resistance tester to detect the grounding resistance value and electrostatic grounding resistance value of the equipment. Test value 〈 4 Ω
Floor plan of electrostatic ground piles in the factory area
Workshop A equipment & human body electrostatic wiring plan
Workshop B Equipment & Human Body Electrostatic Wiring Floor Plan
C workshop equipment & human body electrostatic wiring plan
Ground Resistance Test Method
Test Tool Preparation:
1. Earth Resistance Tester. (Model: ZC29B-1 Place of Origin: Shanghai)
2. Universal Table. (Model number: CFLUKE)
3. 3 grounding wires with clips. (20m gray and black 1 piece, blue 5m 1 piece)
4. 2 grounding test pins. (There is burial at the grounding site, and the spacing is 10 meters)
Test Method: (as shown on the left)
1. Confirm whether the instrument is calibrated and whether it is within the expiration date.
2. Insert the test grounding pin into the soil, spaced more than 10m apart.
3. Adjust the E pointer to X1 and the D pointer to 0 on the instrument.
4. Connect to the grounding wire, instrument A is connected to the gray wire, B is connected to the black wire, and C is connected to the test point (equipment grounding or electrostatic grounding).
5. Turn the instrument handle G with your right hand, and confirm the F pointer while turning D with your left hand, and confirm the reading on D when the pointer is adjusted to 0.
The equipment grounding wire is distinguished from the electrostatic grounding wire
Anti-static measures > standards
Electrostatic Equipment Expansion Content
Human body electrostatic bracelet alarm
Purpose: 1. Prevent employees from forgetting to connect the electrostatic bracelet when they come back after leaving the post;
2. Prevent the poor connection of the electrostatic bracelet during the operation of the employee and fail to be discovered in time.
Introduction to equipment grounding
Purpose of equipment grounding:
Leakage currents, electrostatic charges, and lightning currents that may be generated on electrical equipment and other production equipment are introduced into the ground to avoid electric shock to people and possible fires. Explosion accidents.
Equipment Grounding Method:
Grounding is achieved by connecting a metal wire to a grounding device.
Equipment Grounding Requirements:
All electrical equipment should be grounded to the power supply.
The potential difference between points should be less than 5 [Vac] or less than 10 [Ω]
The equipment grounding wire is used as standard
1. The power cord has three cores with a grounding wire, and the plug uses a three-pin grounding plug. (as shown below)
2. The grounding wire of the equipment is yellow-green mixed color wire Φ3mm or above. (as shown below)
3. The connection must be fixed with terminal blocks.
3. ESD/EOS inspection operation standards
ESD inspection standards
EOS inspection standards