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1. Processing and Laying of Cable Pipes
1) Metal cable ducts should not have perforations, cracks, significant unevenness and severe corrosion, etc. The inner wall of the pipe should be smooth without burrs. After bending, the cable tube should not have cracks or significant indentations. The degree of bending should be no more than 10% of the outside diameter of the tube. The nozzle should be made into a horn or polished.
2) The inner diameter of the cable tube should not be less than 1.5 times the outer diameter of the cable, and the bending radius should meet the requirements for the bending radius of the cable. Each cable tube should not exceed three elbows. There should be no more than two right angles.
3) The connection of the cable tube should meet the following requirements:
a. The metal pipe should adopt a large-sized short pipe sleeve joint. The short pipe is tightly welded at both ends. When the screw pipe is used to connect, the joint seals well.
b. When inserting or inserting the metal pipe, the depth of insertion should not be less than 1.1 to 1.8 times the inner diameter. The adhesive surface should be coated with a glue and sealed. When the socket is used, both ends of the sleeve should be sealed to ensure firmness and sealing.
c, thin-walled steel pipe welding connection is strictly prohibited.
4) When the thin-walled steel pipe is used as a cable pipe, the surface shall be painted with anti-corrosion paint (the pipe embedded in the crucible may not be painted); when the galvanized pipe is used, the anti-corrosion paint shall be applied on the peeled off part of the galvanized layer.
5) The position of the cable pipe leading to the device shall be convenient for the connection of the device and shall not prevent the device from being disassembled and in and out. The cable ducts laid side by side should be arranged neatly.
6) When using the protective tube of the cable as the grounding wire, the grounding wire should be welded first and then the cable should be laid. Where there is a threaded joint, jumpers shall be welded.
7) When the tube enters the box (box), it shall be straight and the length exposed in the box (box) shall be equal to or less than 5mm. The tube fixed with the lock nut shall have 2 to 4 buckles to expose the threads of the lock nut.
2. Preparation and installation of cable trays
1) Cable trays and accessories should be properly stored and stored, should not cause deformation and damage, and should have product certification.
2) Cable bridges shall be installed securely, horizontally and vertically, their vertical deviation shall not be greater than 2/1000 of their length, and the horizontal error shall not be greater than 2/1000 of the width.
3) Cable bridges shall be coated with anti-corrosion primer at the non-standard parts and welding sites produced on site. The top coat shall be uniform and complete with the same color difference.
3, the laying of cables:
Process: Material 1 transport, storage - cable tube laying and cable tray installation - insulation resistance test before cable installation - cable laying.
1) Before the cable is laid, check the completeness of the bridge frame and the integrity of the paint. The cable type, voltage, and specification should be in accordance with the design and product certification.
2) When laying the cable, spare length should be left in the terminal and cable bridge or cable trench.
3) When the cable is laid vertically on the bridge, the power cable must be fixed at both the head and end of the cable, and at both ends of the joint.
4) The bending radius of the plastic insulated cable is not less than 10 times the outer diameter of the cable.
5) When laying the cable, the cable should be led out from the top of the plate. The cable should be prevented from being dragged on the bracket and the ground. The cable surface must not be mechanically damaged.
6) When cables are laid, they should not be crossed. The cables should be arranged neatly. The cable terminators, cable connections, and cable wells should be equipped with signage at both ends. The signboards should be marked with the line number (when the design has no number, it should be marked The type, size and location of the pick-up shall be clearly legible and will not fall off easily. The signs should be uniform in specifications and should be capable of anti-corrosion and solid mounting.
7) When the cable enters the cable channel, building, plate (cabinet) and penetrating into the pipe, the entrance and exit shall be closed and the nozzle shall be sealed.
8) Before making cable terminations and cable joints, make a good inspection to ensure that the phase is correct and that the insulation material should meet the requirements.
4, wiring project
Process: piping - pipe threading
1) This project is a concealed pipeline. The lines that are concealed in the ceiling of the combustible materials for renovation, the surface laid in the wet place or buried in the ground shall be covered with metal pipes, and the lines used for the open or dark places in the dry place may be PVC wires. tube. The AC circuit that runs through the metal pipe should be laid in different circuits and should not be laid with the pipe. The same circuit should not be laid in charge. The distance between the fixed point of the metal pipe when it is applied and the net distance when it is laid and intersected with Other pipes on the same side shall meet the construction specifications and design requirements.
When the pipeline line is long, the junction box should be properly installed, the straight part should not exceed 30m, one bend should not exceed 20m, two bends should not exceed 15m, and three bends should not exceed 8m.
After the metal pipe is laid, check the number of roots, pipe diameters and starting points, and repair the missing and those that do not meet the requirements of the drawings and the current construction specifications.
2) The pipe threading should be performed after the plastering of the building and the ground work. Before threading, the water and debris in the tube should be removed. The conductors shall not have joints and kinks in the pipes, and their joints shall be connected within the junction box.
3) After the wire penetrates into the steel pipe, it should be installed at the outlet of the wire, and the protective wire should be installed. When it does not enter the vertical nozzle in the box (box), the pipe mouth should be used as a seal after penetrating the wire.
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