Wire and cable question and answer
2023-09-10 04:08:45
1. What is the role of the cable sheath?
A: The inner sheath is protected from mechanical damage and chemical corrosion, enhancing mechanical strength.
2, outdoor cable ditch should meet what requirements?
Answer: The upper part of the cable trench should be slightly higher than the ground. Covers should be covered with concrete. The cable should be laid flat on the bracket and have a good drain.
3. What is the role of the sheath in the cable?
Answer: The insulation layer will not be in contact with water, air or other objects to prevent the insulation from moisture and the insulation layer from mechanical damage.
4. What should I pay attention to when using wire cutters?
A: Before use, be sure to check the insulating handle insulation is intact, use wire cutters can not be cut over the specifications allow the metal wire, and the use of wire cutters instead of a hammer to beat the tool to avoid damage.
5, what is the insulation strength?
A: In the electric field, when the electric field strength increases to a certain limit, the insulation material will be broken down. This electric field strength that causes insulation breakdown is called the insulation strength.
6. What are the requirements for the mechanical strength of the cable conductor connection point?
A: The mechanical strength of the connection point is generally lower than the tensile strength of the cable conductor itself. For a fixedly installed power cable, the tensile strength of the connection point is not less than 60% of the tensile strength of the conductor itself.
7. What are the main properties of the insulating material of power cables?
A; should have the following main features:
(1) High breakdown strength;
(2) Low dielectric loss;
(3) High insulation resistance;
(4) Excellent resistance to discharge performance;
(5) Has a certain degree of flexibility and mechanical strength;
(6) Long-term stability of insulation performance.
8. What are the traction strength requirements when laying cables?
A: For copper core cables, when pulling the head, the allowable traction strength is 70N/cm; for the aluminum core cable, when the head is pulled, the allowable traction strength is 40N/cm; if the wire mesh cover is used for traction, the lead protection Set cable allowable strength is 10N/cm; lead sheath cable is 40N/cm.
9. What are the rules for cable protection tubes?
Answer: (1) When the cable needs to wear a protective tube, the inner diameter of the pipe should not be less than 1.5 times the outer diameter of the cable, and the inner diameter of the concrete pipe, clay pipe, asbestos, cement pipe should not be less than 100mm;
(2) The bending radius of the cable tube shall comply with the requirements for the bending radius of the cable to be penetrated;
(3) Each pipe should not have more than three elbows and no more than two right angle bends.
10. How to measure the outer diameter of the cable sheath?
A: At the five points evenly distributed around the jacket circumference, measure the outer diameter of the jacket and its average value. The average outer diameter is the outer diameter of the jacket.
11. How to connect copper cables with different cross-sections?
Answer: The copper cables with different cross-sections can be connected by using open weak copper back-ends and connected by soldering. Copper can also be connected by pure copper rods according to different cross-section requirements and connected by crimping.
12. Summarize the process of heat-shrinking a 10KV cross-connect cable to make an indoor terminal.
Answer: (1) Preparation phase: Check whether the heat shrinkable cable accessories are complete and whether the model is matched. After checking and confirming whether there is moisture in the cable, check the cable.
(2) Exclude excess cables, and determine the cable length according to site conditions.
(3) Strip the cover.
(4) Weld the ground wire and solder the ground wire to the strip.
(5) Fill the trifurcation and wrap the sealant.
(6) Install a three-core branch sheath, put the sheath into the root, and start contracting from the middle, first to the root and then to the finger.
(7) Strip the copper strip and the outer semi-conductive layer, and strip the copper strip with more than 20mm of the three-core branching. Do not damage the main insulation and remove the clean semi-conductive layer.
(8) Install the stress tube and heat shrink the joints at the end of the nozzle.
(9) Install the terminal block.
(10) Install the insulation tube.
(11) Install the sealing tube.
(12) Install the phase tube after the nuclear phase.
13. What are the indoor and outdoor prefabricated terminal installation steps?
Answer: (1) Place the cable in position, fix it, clean the surface according to the predetermined position, and remove the sheath with reference to the instruction manual. If special requirements are required, the length of the outer sheath stripping can be adjusted, and the copper strip and the outer sheath can be installed separately. 2 ground lines.
(2) From the outer jacket mouth up to take the required size, remove the excess cable, insert the heat shrinkable three-finger sleeve to the root of the three prongs and heat shrinkage from the middle, the upper part of the fingertips to measure the specified size (35kv to 350 ~ 380mm ). Remove the excess copper tape (retain 20mm), and then keep the semiconductor at a predetermined position, crimping the outlet terminal seal.
14, the application of wire and cable are mainly divided into three categories:
1. The wire and cable products used in the power system of the power system mainly include overhead bare wires, bus bars (bus bars), power cables (plastic cables, oil-paper cables (substituted by plastic power cables), rubber sleeve cables, and overhead insulated cables. ), branch cables (replace some of the busbars), electromagnetic wires, and electrical equipment.
2. Information Transmission System Wire and cable used for information transmission system mainly includes local telephone cable, television cable, electronic cable, radio frequency cable, optical fiber cable, data cable, electromagnetic wire, power communication or other composite cables.
3, machinery and equipment, instrumentation system This section except for overhead bare wires, there are applications for almost all other products, but mainly power cables, electromagnetic wires, data cables, instrumentation cables and so on.
A: The inner sheath is protected from mechanical damage and chemical corrosion, enhancing mechanical strength.
2, outdoor cable ditch should meet what requirements?
Answer: The upper part of the cable trench should be slightly higher than the ground. Covers should be covered with concrete. The cable should be laid flat on the bracket and have a good drain.
3. What is the role of the sheath in the cable?
Answer: The insulation layer will not be in contact with water, air or other objects to prevent the insulation from moisture and the insulation layer from mechanical damage.
4. What should I pay attention to when using wire cutters?
A: Before use, be sure to check the insulating handle insulation is intact, use wire cutters can not be cut over the specifications allow the metal wire, and the use of wire cutters instead of a hammer to beat the tool to avoid damage.
5, what is the insulation strength?
A: In the electric field, when the electric field strength increases to a certain limit, the insulation material will be broken down. This electric field strength that causes insulation breakdown is called the insulation strength.
6. What are the requirements for the mechanical strength of the cable conductor connection point?
A: The mechanical strength of the connection point is generally lower than the tensile strength of the cable conductor itself. For a fixedly installed power cable, the tensile strength of the connection point is not less than 60% of the tensile strength of the conductor itself.
7. What are the main properties of the insulating material of power cables?
A; should have the following main features:
(1) High breakdown strength;
(2) Low dielectric loss;
(3) High insulation resistance;
(4) Excellent resistance to discharge performance;
(5) Has a certain degree of flexibility and mechanical strength;
(6) Long-term stability of insulation performance.
8. What are the traction strength requirements when laying cables?
A: For copper core cables, when pulling the head, the allowable traction strength is 70N/cm; for the aluminum core cable, when the head is pulled, the allowable traction strength is 40N/cm; if the wire mesh cover is used for traction, the lead protection Set cable allowable strength is 10N/cm; lead sheath cable is 40N/cm.
9. What are the rules for cable protection tubes?
Answer: (1) When the cable needs to wear a protective tube, the inner diameter of the pipe should not be less than 1.5 times the outer diameter of the cable, and the inner diameter of the concrete pipe, clay pipe, asbestos, cement pipe should not be less than 100mm;
(2) The bending radius of the cable tube shall comply with the requirements for the bending radius of the cable to be penetrated;
(3) Each pipe should not have more than three elbows and no more than two right angle bends.
10. How to measure the outer diameter of the cable sheath?
A: At the five points evenly distributed around the jacket circumference, measure the outer diameter of the jacket and its average value. The average outer diameter is the outer diameter of the jacket.
11. How to connect copper cables with different cross-sections?
Answer: The copper cables with different cross-sections can be connected by using open weak copper back-ends and connected by soldering. Copper can also be connected by pure copper rods according to different cross-section requirements and connected by crimping.
12. Summarize the process of heat-shrinking a 10KV cross-connect cable to make an indoor terminal.
Answer: (1) Preparation phase: Check whether the heat shrinkable cable accessories are complete and whether the model is matched. After checking and confirming whether there is moisture in the cable, check the cable.
(2) Exclude excess cables, and determine the cable length according to site conditions.
(3) Strip the cover.
(4) Weld the ground wire and solder the ground wire to the strip.
(5) Fill the trifurcation and wrap the sealant.
(6) Install a three-core branch sheath, put the sheath into the root, and start contracting from the middle, first to the root and then to the finger.
(7) Strip the copper strip and the outer semi-conductive layer, and strip the copper strip with more than 20mm of the three-core branching. Do not damage the main insulation and remove the clean semi-conductive layer.
(8) Install the stress tube and heat shrink the joints at the end of the nozzle.
(9) Install the terminal block.
(10) Install the insulation tube.
(11) Install the sealing tube.
(12) Install the phase tube after the nuclear phase.
13. What are the indoor and outdoor prefabricated terminal installation steps?
Answer: (1) Place the cable in position, fix it, clean the surface according to the predetermined position, and remove the sheath with reference to the instruction manual. If special requirements are required, the length of the outer sheath stripping can be adjusted, and the copper strip and the outer sheath can be installed separately. 2 ground lines.
(2) From the outer jacket mouth up to take the required size, remove the excess cable, insert the heat shrinkable three-finger sleeve to the root of the three prongs and heat shrinkage from the middle, the upper part of the fingertips to measure the specified size (35kv to 350 ~ 380mm ). Remove the excess copper tape (retain 20mm), and then keep the semiconductor at a predetermined position, crimping the outlet terminal seal.
14, the application of wire and cable are mainly divided into three categories:
1. The wire and cable products used in the power system of the power system mainly include overhead bare wires, bus bars (bus bars), power cables (plastic cables, oil-paper cables (substituted by plastic power cables), rubber sleeve cables, and overhead insulated cables. ), branch cables (replace some of the busbars), electromagnetic wires, and electrical equipment.
2. Information Transmission System Wire and cable used for information transmission system mainly includes local telephone cable, television cable, electronic cable, radio frequency cable, optical fiber cable, data cable, electromagnetic wire, power communication or other composite cables.
3, machinery and equipment, instrumentation system This section except for overhead bare wires, there are applications for almost all other products, but mainly power cables, electromagnetic wires, data cables, instrumentation cables and so on.
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