Wiring techniques is a very important step in cable installation. If the quality of wiring is good, the quality of electrical installation projects can be guaranteed. According to the insulation material, cables are oil-impregnated paper insulation, plastic insulation, and rubber insulation. As for the outer sheath, there are armored and unarmored cables. According to the purpose, there are high-voltage and low-voltage power cables, as well as control cables and communication cables.
Wiring techniques is divided into indoor wiring and outdoor wiring. Indoor wiring is divided into open wiring and concealed wiring. For outdoor wiring, there are many methods such as bridges, wall brackets, steel cable hangers, cable tunnels, cable trenches, direct burial, etc. The wiring method should be determined according to the specific conditions such as environmental requirements, the number of cables, and the voltage level. The choice of cable project wiring method depends on the conditions of the project, the characteristics of the environment, and the types and quantity of cables. It should be selected according to the requirements of reliable operation and convenient maintenance, as well as the principles of technical and economic rationality. Next, this article will share with you 10 questions and answers about wiring techniques, hoping to help you.
What inspections should be carried out before wiring?
The brackets should be complete and the paint should be intact.
The cable model, voltage and specifications should meet the design.
The cable insulation is good. When there is doubt about the sealing of the oil-paper cable, it should be judged whether it is damp; the direct buried cable and the small bottom cable should pass the DC withstand voltage test; the oil sample of the oil-filled cable should pass the test.
The oil pressure of the oil-filled cable should not be lower than 1.47MPa.
When there is doubt about the sealing of the oil-paper insulated power cable, how to use a simple method to check whether the cable insulation paper is damp?
Ignite the cable insulation paper or put it in the cable oil at about 150°C for inspection. If there is no “hissing” sound or white foam, it means that it is not damp.
What should the cable sign indicate? What are the requirements for writing techniques?
The cable line design number, cable model, specification and starting point should be indicated on the sign. Cables used in parallel should have a sequence number. The writing should be clear and not easy to fall off.
Where should the azimuth mark of the direct buried cable be set?
At both ends of the cable, at the cable joint at 50~100m of the straight section of the cable, and at the corner where the cable changes direction.
How to dehumidify the yellow wax silk tape, black glass paint tape, alkali-free glass ribbon, etc. used to make cable joints before construction?
Constant temperature drying method: roll the insulating tape into a small roll with a diameter of 25~30mm, put it in a constant temperature drying oven at 110~120℃ for 4~5h, cool it and take it out, and put it in a dry sealing cylinder.
Oil immersion dehumidification method: put the small roll of insulating tape into the cable oil at a constant temperature of 120~130°C, keep it 30mm away from the bottom of the pot, take it out after a certain period of time when the oil surface no longer produces foam, put it into the barrel containing cable oil, and the oil level should exceed all the objects put in and seal it.
What is the function of the cable outer sheath?
Protect the inner sheath from mechanical damage and chemical corrosion and enhance mechanical strength.
What requirements should outdoor cable trenches meet?
The upper part of the cable trench should be slightly higher than the ground, and covered with a cover made of concrete. The cable should be laid flat on the bracket and have a good drainage pipe.
What is the role of the inner sheath of the cable?
Answer: To prevent the insulation layer from contacting with water, air or other objects, to prevent the insulation from getting damp and the insulation layer from being mechanically damaged.
What should be paid attention to when using wire cutters?
Before use, be sure to check whether the insulation of the insulating handle is intact. When using, wire cutters must not be used to cut metal wires that exceed the specifications allowed, and wire cutters are prohibited from being used instead of hammers to hit the tool to avoid damage.
10. What is insulation strength?
Insulating materials in an electric field will be broken down when the electric field strength increases to a certain limit. The electric field strength that causes insulation breakdown is called insulation strength. Public account head I am inductive, etc.
Post time: Oct-30-2024
