(2) In order to reduce the shielding effect of adjacent grounding bodies, when burying grounding bodies, the spacing between vertical grounding bodies should not be less than twice its length; The spacing between horizontal grounding bodies should not be less than 5m. The distance between the building and the grounding body should not be less than1.5m.
(3) The connection between electrical equipment and grounding wire generally includes two methods: threaded connection and welding connection. Threaded connections are suitable for equipment that needs to be moved (such as transformers). If the electrical equipment is installed on a metal structure with reliable metal contact, the neutral wire or grounding wire can be directly welded on the metal frame.
There are usually special grounding screws on the shell of electrical equipment. When connecting the grounding wire with screws, remove the screws and wipe the contact surface between the equipment and the grounding wire to metallic luster. Hang the solder on the end of the grounding wire and coat it with neutral vaseline oil. Then insert the screw and tighten the nut. Where there is vibration, all grounding screws must be padded with spring coils to prevent vibration from loosening. If the grounding wire is flat steel, it should be drilled with a drilling machine or a hand electric drill, and gas welding cutting is not allowed.
Portable electrical equipment shall be grounded with special core wire for portable conductor, and neutral wire shall not be used for grounding. The neutral wire and the grounding wire should be connected to the grounding grid respectively. When copper conductor is used, its cross section shall not be less than1.5mm2.
(4) When the grounding wire is connected to the extended grounding (such as pipeline), it should be welded near the entrance of the building. When the connection between the ground wire and the pipeline cannot be welded, a clamp should be used for connection, the contact surface of the clamp should be tinned, and the pipe joint should be cleaned. The valves, water meters and flanges on the pipeline shall be bridged by bare wires.
The connection between grounding wires and the connection between grounding wires and electrical equipment shall be lap welded. The length of lap welding is: the round steel is not less than 6 times its diameter, and it must be welded on more than three sides; Angle steel or flat steel is not less than 2 times its width.
When welding flat steel with steel pipe (or angle steel), in addition to welding on both sides, arc (or right angle) clips bent by steel strip should also be welded, or the steel strip itself should be bent into arc (or right angle) and welded with steel pipe (or angle steel) to make the connection reliable. The distance between the steel strip and the top of the steel pipe (or angle steel) should be about100 mm.
When using natural conductors such as steel bars, steel pipes and crane tracks in buildings as grounding conductors, the joints shall ensure reliable contact and uninterrupted length. The joints of metal structures shall be welded with steel belts with a cross section not less than 100mm2, and the joints between metal structures and their joints shall be painted with Zhang Dan after welding.
When steel pipes are used as grounding wires, there should be reliable joints. When laying openly or secretly in neutral grounding power grid, two points should be spot-welded on both sides of steel pipe joint.
(5) The exposed grounding wire shall be painted with various colors according to the following provisions. Exposed grounding wires and fixtures shall be painted black. According to the decoration form of the room, the exposed ground wire can also be painted in other colors, but two black belts with the width of 1.5mm should be painted at the joints and branches, and the spacing is150 mm; ; The conductor or flat steel of the grounding phase of electrical devices above 1000V shall be painted with the same color as the phase line, and a black stripe with the width of 15mm shall be painted every 150mm; The grounding conductor and flat steel with exposed neutral point shall be painted with purple paint, and a black paint ring with a width of 15mm shall be painted every150 mm.. The above colored paints shall have corrosion resistance and shall be painted uniformly.
20 18-08- 14 answer
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A small problem of grounding conductor
First of all, it must be clear that the charge moves if and only if there is a potential difference. At first, the metal conductor and the earth are equipotential (the earth, uncharged body and infinity all think that the potential is 0). At the moment of charging, because it is a positive charge (let's just say that it was discovered by Madame Curie), its potential decays from itself to infinity to zero. Because infinity and the earth are considered equipotential, there is a potential difference between the metal plate and the earth. At this point, the metal plate and the earth are no longer equipotential bodies. So the charge begins to flow (or redistribute), and the positive charge flows from the metal plate to the earth. When the positive charge flows to the earth, because the earth is infinite, we think that the potential of the earth will not be affected (just like disappearing) after the charge flows to the earth. So the positive charge keeps flowing to the earth until all the charges on the metal plate flow to the earth. At this time, the metal plate is no longer charged, and the potential returns to 0, which is equal to the earth. Without potential difference, the current disappears. To sum up, there will be a current, but it will be short (specifically, the current decays with a negative natural logarithmic function. If you want to know, please tell me, and I will use calculus to deduce it for you. Then the power went out. I hope it helps you #
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How to connect copper foil to anti-static ground wire? Is it buried underground or is it directly led out by copper foil?
First, we need to clarify a few issues. Copper foil is buried under the self-leveling ground, not wires. Conductors are used for indoor wiring. The connection between copper foil and grounding conductor is mostly completed through terminals (generally 6 terminals). As for the resistance of one megohm, I don't know why it should be connected to the wire. Under normal circumstances, according to the ESD S20.20 standard, such a resistor is not needed in the wiring stage.
Shang Fan 1978
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