Basic characteristics of aviation aluminum alloy

The main characteristics of aluminum alloys for aerospace are: large-scale and integration, thin-walled and lightweight, precision of section size and geometric tolerance, uniformity and quality of microstructure and properties. According to different service conditions and parts of aircraft, aluminum alloys for aerospace are mainly high-strength aluminum alloy, heat-resistant aluminium alloy and corrosion-resistant aluminum alloy. High strength aluminum alloy is mainly used for aircraft fuselage components, engine compartment, seats, control systems, etc., and is the most widely used,For example, 5086 aluminum alloy.

characteristics of aviation aluminum alloy

The biggest characteristic of aviation aluminum alloy is that it can improve the strength by deformation heat treatment. Deformation heat treatment is a comprehensive process that combines the deformation strengthening of plastic deformation with the phase transformation strengthening during heat treatment to unify the forming process and formability. During the plastic deformation process of aviation aluminum alloy, the defect density inside the crystal increases, and these crystal defects will cause the change of the internal microstructure of the material. In the process of plastic deformation of aviation aluminum alloy, dynamic recovery, dynamic recrystallization, sub dynamic crystallization, static recrystallization, static recovery and other crystal structure changes will occur. These changes in crystal structure, if properly controlled, will significantly improve the mechanical properties of the material and enhance the service life of the material.

Aeronautical aluminum alloys are generally strengthened by precipitation of dispersed phase in supersaturated solid solution. The general precipitation sequence is: segregation region (or GP region) ~ transition phase (metastable phase) ~ equilibrium phase. In the process of deformation heat treatment, deformation induces precipitation, precipitation affects deformation, deformation and precipitation affect each other, and dynamically affect the properties of the material.

characteristics of aviation aluminium alloy

The precipitation strengthening process of deformation heat treatment is greatly affected by temperature. Deformation heat treatment can be divided into high temperature deformation heat treatment and low temperature deformation heat treatment. The basic processes of low temperature deformation heat treatment are: quenching of aviation aluminum alloy, cold deformation at room temperature and aging heat treatment. After this treatment, the strength of aviation aluminum alloy is greatly improved, but the plasticity is reduced. High temperature deformation heat treatment process: quenching, high temperature deformation and aging. After high temperature deformation heat treatment, the strength of the material is higher, the plasticity and toughness are improved, and the heat resistance strength of the alloy is also improved.

What are the commonly used low-voltage power cables?

(1) Classification of low-voltage power cables
Low-voltage power cables are generally divided into polyvinyl chloride insulated (plastic) power cables, XLPE insulated power cables, rubber insulated power cables, oil-filled and oil-impregnated paper insulated power cables according to their insulation types, and can be divided according to their work types and properties. It is a type of general ordinary power cable, overhead power cable, mine underground power cable, submarine power cable, fire-resistant (fire-resistant) flame-retardant power cable, etc.
(2) Several commonly used low-voltage power cables and their characteristics
1. Copper core conductor power cable
At present, all low-voltage power cables in China are twisted together by each core wire. The cable with this structure has poor anti-interference ability and poor lightning resistance performance. The three-phase impedance of the cable is unbalanced and the zero-sequence impedance is large, which makes it difficult to protect the line. Electrical appliances operate reliably, etc. The copper and aluminum PVC copper core conductor power cables with rated voltages of 0.6kv ~ 1kv

2. XLPE insulated power cable
Referred to as XLPE cable, it uses chemical or physical methods to change the molecules of the cable’s insulating material polyethylene plastic from a linear structure to a three-dimensional network structure, that is, to convert the original thermoplastic polyethylene into a thermosetting cross-linked polyethylene. Plastic, which greatly improves the heat resistance and service life of the cable, and still maintains its excellent electrical properties.
3. PVC insulated PVC sheathed power cable
The long-term working temperature of PVC insulated and PVC sheathed power cables does not exceed 70 °C, and the maximum temperature of the cable conductor does not exceed 160 °C. The longest duration of short circuit shall not exceed 5s, and the minimum temperature of construction and laying shall not be lower than 0℃.

XLPE insulated cable eccentricity control details

1. Wire drawing and twisting
Qualified products are not detected, but manufactured. For the control of 110kv cable eccentricity, each department in the cable enterprise has corresponding quality control responsibilities. Here we mainly talk about the understanding and detailed control of conductor preparation and tooling level. When designing a conductor, people give priority to or often only consider the reference conductor carrying capacity and conductor DC resistance. This is not enough for 110kv and above power cables. The roundness and straightness of the conductor often affect the XLPE insulation material. Distribution, which in turn affects the electric field distribution in the cable; the monofilament ductility of the conductor filaments will affect the cable insulation stress; the conductor surface quality (such as oxidation caused by improper storage, conductor knocks in the disk flow, etc.) on the current carrying capacity Wait. In the process of drawing, if the concentration and temperature of the emulsion are not regularly checked and replaced according to the standard, it is very likely that the monofilament will be oxidized in the drawing. In the conductor stranding process, the conductor protection is insufficient. Some companies have installed online DC resistance measuring instruments but do not use them. Some companies produce high-voltage cables according to the habit of producing low- and medium-voltage cables, even when they are producing 110kv cables because of the absence of staff on duty. , The personnel are transferred from the production line of low-voltage cables. These ideological understanding and detailed control will seriously affect the eccentricity control of the cable, but they are often ignored due to people’s experience. Uneven cable field strength distribution caused by scratches is an undesirable result.

2. Preservation and scientific use of insulating materials (including insulation, conductor shielding, and insulating shielding)
The transportation, storage and use of 110kv XLPE insulation material have strict requirements. The XLPE transportation link is not controlled by the cable company but is controlled by the cable material supplier. However, the cable company should also put forward corresponding requirements. The climate in the south is humid (install indoor temperature control equipment, balance humidity and temperature, and store cable materials at room temperature) and so on. When cable companies store XLPE cable materials, they should make unified arrangements and establish special insulation materials and shielding materials storage rooms to prevent material deterioration or abnormalities caused by climate change. There are only a handful of cable material companies in China that produce 110kv and above. Most of the ultra-high voltage XLPE insulation materials are imported from Borealis, Dow Chemical and other foreign companies. Due to language differences, most of the materials’ certificates are in English, and there is no Obvious production date and shelf life identification, using codes or codes that only cable material manufacturers can understand, this brings great inconvenience to cable material users. When the cable material is used in batches, the most contacted cable material is Workshop operators rarely understand English. The author had previously suggested a cable material foreign company, but only got a vague answer. This is because UHV cable materials belong to the seller’s market and are monopolized by a few companies. It is recommended that domestic cable companies must clarify the transportation conditions, production date, shelf life and Chinese-English bilingual instructions when purchasing UHV cable materials. In addition, XLPE insulation, shielding material storage rooms and inter-connection operation rooms should be prohibited from entering and exiting non-duty operators as much as possible. When there are special circumstances, dust removal work must be done to avoid cable breakdown due to a strand of hair. If conditions permit, companies can install monitors in the storage room to increase assessment efforts so that all employees can realize the huge impact of high-voltage and ultra-high-voltage insulation materials on cables.
3. Process technology
The XLPE insulated cable cross-linking production line in the cable industry in the world basically has two methods: catenary and tower. In recent years, the discussion of which is better for catenary and tower has been going on. According to public information, if China Nearly 60 vertical towers have all cross-linked lines in full production, which can meet the world’s demand for high-voltage and ultra-high-voltage cables. Therefore, the 21st order of the Development and Reform Commission in 2013 on the addition of 6KV and above dry-type cross-linking production lines to the cable industry limits.
The technical factors that affect the eccentricity of the cable insulation also include: the specifications of the extrusion die, the stress of the XLPE insulating material, the operating temperature and speed of the cross-line, the skill level of the operators, and so on.For more cable knowledge, please follow Chris’s cable.

Types of cables for photovoltaic power generation systems

Photovoltaic special cables, power cables, control cables, communication cables, radio frequency cables
Photovoltaic cable: PV1-F1*4mm2
The cable from the string to the combiner box is generally used: photovoltaic special cable PV1-F1*4mm2.
Features: The photovoltaic cable has a simple structure. The polyolefin insulation material used in it has excellent heat resistance, cold resistance, oil resistance, and ultraviolet resistance. It can be used under harsh environmental conditions and has a certain mechanical strength.
Laying: It can be protected through the pipe, and the component bracket is used as the channel and fixing of the cable laying to reduce the impact of environmental factors.
Power cable: ZRC-YJV22
Steel tape armored flame-retardant cross-linked cable ZRC-YJV22 is widely used in: combiner box to DC cabinet, DC cabinet to inverter, inverter to transformer, transformer to power distribution device, power distribution device to the power grid connecting cables.
The common nominal cross-sections of ZRC-YJV22 cables in photovoltaic power generation systems are: 2.5mm2, 4mm2, 6mm2, 10mm2, 16mm2, 25mm2, 35mm2, 50mm2, 70mm2, 95mm2, 120mm2, 150mm2, 185mm2, 240mm2, 300mm2.

(1) The texture is hard, the temperature resistance grade is 90°C, it is easy to use, has the characteristics of low dielectric loss, chemical corrosion resistance and no drop limit for laying.
(2) It has high mechanical strength, good resistance to environmental stress, good thermal aging performance and electrical performance.
Laying: It can be buried directly, suitable for fixed laying, and adapt to the needs of different laying environments (underground, water, trenches and tunnels).
Power cable: NH-VV
NH-VV copper core PVC insulated PVC sheathed fire-resistant power cable. Suitable for rated voltage 0.6/1KV.
Use characteristics: Long-term allowable working temperature is 80°C. Allowable bending radius during laying: single-core cables are not less than 20 times the cable outer diameter, and multi-core cables are not less than 12 times the cable outer diameter. When the cable is laid, the ambient temperature is not lower than 0 degrees Celsius, without pre-heating. The voltage laying is not limited by the drop.
Laying: Suitable for occasions with fire resistance requirements, and can be laid indoors, in tunnels and trenches. Note that it cannot withstand the action of external mechanical forces and can be directly buried in the ground.

Control cable: ZRC-KVVP
ZRC-KVVP copper core PVC insulated PVC sheathed braided shielded control cable. It is suitable for the control, monitoring circuit and protection circuit of AC rated voltage 450/750V and below.
Features: Long-term allowable use temperature is 70℃. The minimum bending radius is not less than 6 times the outer diameter.
Laying: Generally, it is laid indoors, cable trenches, pipes and other fixed places that require shielding and flame retardancy.
Communication cable: DJYVRP2-22
DJYVRP2-22 polyethylene insulated PVC sheathed copper wire braided shielded armored computer special soft cable is suitable for electronic computers and automation connection cables with high requirements for interference prevention at rated voltages of 500V and below.
Features: DJYVRP2-22 cable has the characteristics of oxidation resistance, high insulation resistance, good withstand voltage, and low dielectric coefficient. While ensuring the service life, it can also reduce the crosstalk and external interference between circuits, and the signal transmission quality is high. The minimum bending radius is not less than 12 times the cable outer diameter.
Laying: The cable is allowed to be fixedly laid and used under the ambient temperature of -40℃~50℃. Laying indoors, cable trenches, pipelines and other places that require electrostatic shielding.
Communication cable: RVVP
Copper core PVC insulated PVC sheathed insulated and shielded flexible cable RVVP, also known as electrical connection anti-interference flexible cable, is a communication cable suitable for anti-interference, safe and efficient data transmission, such as alarms and security.
Features: Rated working voltage 3.6/6KV, long-term working temperature of the cable conductor is 90℃, and the minimum allowable bending radius is 6 times the outer diameter of the cable. It is mainly used as a communication cable to play a role in anti-interference. Laying: The RVVP cable should not be exposed to sunlight, and the bottom core must be well grounded. The weak current circuit communication cables that need to suppress the intensity of electrical interference should be laid in steel pipes and boxes. When laying parallel to the power cable, the distance should be kept away as far as possible.
RF cable: SYV
Solid PE insulated and PVC sheathed radio frequency coaxial cable SYV.
Features: The commonly used video cables in monitoring are mainly SYV75-3 and SYV75-5. If you want to transmit video signals within 200 meters, you can use SYV75-3, and if you want to transmit video signals within 350 meters, you can use SYV75-5.
Laying: It can be laid through a pipe.

Small difference between overhead cable and fiber optic cable

Overhead cable: When the phone converts the acoustic signal into an electrical signal and then transmits it to the switch via the line, the switch transmits the electrical signal directly to the other phone via the line for answering. The transmission line during this conversation is the cable. The main part of the cable is copper core wire. The single core wire diameters are divided into 0.32mm, 0.4mm and 0.5mm. The larger the diameter, the stronger the communication capability; and according to the number of core wires, there are: 5 pairs, 10 pairs, 20 pairs, 50 pairs, 100 pairs, 200 Yes, wait, the logarithm mentioned here refers to the maximum number of users that the cable can accommodate; it is also divided by package.
Optical fiber cable: It is large in size, weight, and poor in communication ability, so it can only be used for short-distance communication. Optical cable: When the phone converts the acoustic signal into an electrical signal and then transmits it to the switch via the line, the switch transmits the electrical signal to the photoelectric conversion device (converts the electrical signal into an optical signal) and transmits it to another photoelectric conversion device via the line ( Convert optical signals into electrical signals), and then to the switching equipment, to another phone to answer. The line between the two photoelectric conversion devices is an optical cable. Gu said that it is only divided by the number of core wires, the number of core wires: 4, 6, 8, 12 pairs and so on.

Optical cable: It has the advantages of small size, weight, low cost, large communication capacity, and strong communication capability. Due to many factors, it is currently only used for long-distance and point-to-point (ie, two switch rooms) communication transmission. Their difference: the inside of the cable is copper core wire; the inside of the optical cable is glass fiber. Optical fiber communication optical cable is a kind of communication line in which a certain number of optical fibers form a cable core in a certain way, and are covered with a sheath, and some are also covered with an outer sheath to realize the transmission of optical signals. Field tests have been carried out successively in Shanghai, Beijing, Wuhan and other places. Soon after, it was tried out as an intermediate trunk in the local telephone network. After 1984, it was gradually used for long-distance lines, and single-mode fiber was adopted. Communication optical cables have greater transmission capacity than copper cables, with long relay sections, small size, light weight, and no electromagnetic interference. Since 1976, they have developed long-distance trunk lines, intra-city relays, offshore and transoceanic submarine communications. , As well as the backbone of wired transmission lines such as local area networks and private networks, and began to develop into the field of user loop distribution networks in the city, providing transmission lines for fiber-to-the-home and broadband integrated service digital networks. The cable is usually a rope-like cable that is twisted by several or several groups of wires (at least two in each group). Each group of wires is insulated from each other and is often twisted around a center. The entire outer bread has a height. Insulating coating; especially the submarine cable first: there is a difference in material. Cables use metal materials (mostly copper and aluminum) as conductors; optical cables use glass fibers as conductors. Second: There is a difference in the transmission signal. The cable transmits electrical signals. Optical cables transmit optical signals. Third: There are differences in the scope of application. Cables are now mostly used for energy transmission and low-end data information transmission (such as telephone). Optical cables are mostly used for data transmission.

What is a photovoltaic cable?

The construction of cost-effective and profitable photovoltaic power plants represents the most important goal and core competitiveness of all solar manufacturers. In fact, profitability depends not only on the efficiency or high performance of the solar modules themselves, but also on a series of components that seem to have no direct relationship with the modules. For example, if the photovoltaic power station fails to use suitable cables, it will affect the service life of the entire system. So, what is a photovoltaic cable?
Photovoltaic cable is an electron beam cross-linked cable with a rated temperature of 120°C, which is equivalent to 18 years of use under continuous temperature conditions of 90°C; and when the temperature is lower than 90°C, its use Longer life.
The characteristics of photovoltaic cables are determined by their special insulation materials and sheath materials, which are called cross-linked PE. After being irradiated by an irradiation accelerator, the molecular structure of the cable material will change, thereby providing its various performances. During installation and maintenance, the cables can be routed on the sharp edges of the roof structure. At the same time, the cables must withstand pressure, bending, tension, cross tensile loads and strong impacts. If the cable sheath is not strong enough, the cable insulation layer will be severely damaged, which will affect the service life of the entire cable, or cause short-circuit, fire, and personal injury hazards.
Photovoltaic cable selection

The cables used in the low-voltage DC transmission part of the solar photovoltaic power generation system have different requirements for the connection of different components due to different use environments and technical requirements. The overall factors to be considered are: the insulation performance of the cable, the heat-resistant and flame-retardant performance, Engage in aging performance and wire diameter specifications. Specific requirements are as follows:
1. The connecting cable between the solar cell module and the module is generally connected directly with the connecting cable attached to the module junction box. When the length is not enough, a special extension cable can also be used. Depending on the power of the components, this type of connecting cable has three specifications with a cross-sectional area of ​​2.5m㎡, 4.0m㎡, and 6.0m㎡. This type of connecting cable uses a double-layer insulation sheath, which has superior resistance to ultraviolet rays, water, ozone, acid, and salt, as well as superior all-weather capability and abrasion resistance.
2. The connecting cable between the battery and the inverter requires the use of a multi-strand flexible wire that has passed the UL test, and it should be connected as close as possible. Choosing a short and thick cable can reduce the loss of the system, improve efficiency, and enhance reliability.
3. The connecting cables between the battery square array and the controller or DC junction box also require the use of multi-strand flexible wires that have passed the UL test. The cross-sectional area specification is determined by the maximum current output of the square array.
The cross-sectional area of ​​the DC cable of each part is determined according to the following principles: The connecting cable between the solar cell module and the module, the connecting cable between the battery and the battery, and the connecting cable of the AC load. Generally, the rated current of the selected cable is the maximum continuous operation of each cable 1.25 times the current; the connecting cable between the solar cell array and the array, the connecting cable between the battery (group) and the inverter, the cable rated current is generally 1.5 times the maximum continuous working current in each cable.

Production of cables without production license is punished

From the first batch of “iron fist”, there are cables again and again. There’s nothing to say. We’re catching up with the “quality month”. Xiaobian reminds everyone to pay attention. There will be some later. Don’t forget what we said in the early stage. There will be a reward of 1 million for reporting, so someone must have moved this crooked idea in the near future.
On June 15, 2021, the market supervision bureau of Changchun City, Jilin Province imposed an administrative penalty of confiscating 1000 meters of AAAC Cable involved and imposing a fine of 110000 yuan on Jilin Xinda Cable Co., Ltd. for the illegal act of producing extruded insulated low-voltage power cable without obtaining a production license.

On March 18, 2021, the law enforcement officers of Changchun Market Supervision Bureau inspected the business premises of the parties according to the reporting clues, and found that the parties stored extruded insulated low-voltage power cables (model: wdzcyjlv4) on the site × 400+1 × 240; Voltage 0.6/1kv; Sectional area 400mm ²; Manufacturer: Jilin Xinda Cable Co., Ltd.) with a total of 1000m, and the cross-sectional area exceeds the “cross-sectional area ≤ 300mm” allowed by its production license ²” It is suspected to produce extruded insulated low-voltage ACAR Cables without obtaining production license.

After investigation, the extruded insulated low-voltage power cables of the above specifications and models produced by Jilin Xinda Cable Co., Ltd. belong to the products listed in the production license catalogue, and the party concerned has not obtained the production license of the products of the above specifications and models. After consulting the production accounts, sales accounts and sales invoices provided by the parties, the law enforcement officers found that the parties produced 1000 meters of the above illegal products according to the contract, with a price of 110 yuan / meter and a total value of 110000 yuan. Since the products have not been sold, there are no illegal gains. The act of the party concerned violated the provisions of Article 5 of the regulations of the people’s Republic of China on the administration of production licenses for industrial products, and Changchun Market Supervision Bureau imposed administrative penalties on the party concerned according to law.

Power cables are widely used in people’s production and life. The power cables used have quality problems, which may cause short circuit or aging and fire, and there are serious potential safety hazards. Therefore, the State implements production license management for power cables. Strictly investigating and punishing the production of power cables without production license according to law and further strengthening the supervision and management of ACSR Cable product quality are conducive to improving product quality level, clarifying product quality responsibility, protecting the legitimate rights and interests of consumers and maintaining social and economic order.

Precautions for household wire installation

In home decoration, circuit engineering is the most important, and home circuit belongs to concealed engineering, which is related to people’s quality of life and living standard in the future. Therefore, we must pay attention to circuit problems in decoration to avoid potential safety hazards. Next, Guoyou AAC Cable will share the relevant knowledge of family wire laying to protect the safety of family electricity.

1、 Flame retardant wires shall be selected
In modern families, there are too many household appliances and heavy wire load, which is easy to cause fire accidents. In these aspects, flame retardant wires can meet the power demand of families. At the same time, in case of fire hazard, flame retardant wires can effectively control the spread speed of fire, avoid greater losses caused by the fire of combustibles around wires, and strive for more time for people to evacuate from the fire site to minimize the loss of fire injury.

2、 Use wires of different colors
Color classification shall be done well when laying family lines, and it is more convenient for later maintenance. According to national regulations, red, yellow and green represent live wire, light blue is used for zero wire, and yellow and green are used for ground wire. In future maintenance, electricians can distinguish live wire and zero wire through the color of wires, which is convenient for construction and is also very important for household electricity.
3、 Wire laying and pipe sleeve
According to the ACSR Cables laying regulations, the wire must be protected by insulating sleeve during the laying process, and the joint shall not be exposed. Some irresponsible construction teams will directly bury the wires in the wall without casing protection. This treatment leads to the exposed wire joints, which are easy to be damaged by external forces, so as to reduce the service life of the wires and bury potential safety hazards for people’s life.

Unqualified ABC Cables laying will not only affect our use, but also directly affect our life safety. Choosing a high-quality wire product can reduce the risk from the source. Guoyou high-end wire has excellent performance in high temperature resistance, moisture resistance, durability, energy saving and environmental protection, which is different from ordinary household wires, With professional environmental protection and flame retardancy, consumers are more safe and assured to use. The above is the relevant knowledge of family wire laying. I hope it will be helpful to you

Cable threading, tips you don’t know!

In the wiring of weak current projects, we usually bury the wire tube in the wall first. Such a hidden design will not affect the beautiful effect of decoration. However, after the AAAC Cables tube is buried, threading from the inside is a troublesome thing. Sometimes we can’t wear a wire after tossing for a long time. What should we do at this time?

In fact, the reason is that we don’t use the right way to thread wires. Let’s introduce a new way to thread wires. It’s so fast and professional for wires to go through pipes. Teachers and Fu all install it like this. It’s too smart!
What’s good for threading wires
The traditional wire threading method is generally to put a small steel wire in the wire pipe, then bend the steel wire to buckle the outer edge of the pipe, tie the wire to one end of the steel wire, pull the steel ACSR Cables on the other side, and then slowly pull the wire out of the pipe, but this construction method tests patience. Moreover, it will greatly increase the decoration time, and the operation is also more troublesome. If you meet a corner, sometimes it takes half a day to get the line out. So now more and more people are not using this method.
However, with the development of technology, some tools in decoration are constantly updated, so now smart masters no longer use steel wire rope, but use this, which can thread quickly without jamming. Now the outer skin of professional threading device is made of steel wire wrapped rubber, which has good hardness and smoothness. It is much stronger than the previous steel wire rope, and it is not easy to jam at the elbow. In particular, a pulley is installed at the thread feeding head, which is very popular with teachers.
This threading device is also very simple in operation. It can be used for the first time. Use the traction head of the wire to pass through the wire head, and then fix it with a professional tensioner. This kind of tightener not only has good fixing effect, but also is convenient for construction, which saves the threading time of the master. After the thread head passes through the tightener, wrap it into an 8-shaped shape, and then push it up with the fastening spring. It is not too convenient. This is why more and more masters like to use the tightener instead of the steel wire rope.

Let’s introduce several standard threading methods
1. The first is that some wires will be long, or when it is necessary to turn and wind in the actual environment, talc powder can be added to the pipe to facilitate the extraction of wires. Remove a little of the insulation material in the front section of the wire, and then slowly fix the wire core in the coil.
2. The more important point is: wires with different voltages and different circuits must not be threaded in the same conduit. In addition, if the circuits of multiple lamps will not interfere with each other, remember not to thread too much.
3. After the wires are strung, remember to cut off the wires. If you want to connect the blood to the switches, sockets and junction boxes, we remember to reserve more than 15 cm. In addition, more than half of the perimeter of the distribution box should be left in the distribution box. Oh, the wires outside the door should be left about one and a half meters.
Wire threading cannot be carried out casually, and the following points shall be ensured
1. Be sure to select wires with good quality and large wire diameter. The threading pipe shall be flame-retardant PVC pipe. When purchasing, you can pinch it with your fingers. If it can’t be broken, it means that the quality is very good. If the economy permits, special galvanized pipe can also be selected.
2. In the same conduit, the number of wires passing through shall not be too much, and it shall be easy to pull. The popular standard is that the total cross-sectional area of the wires in the pipe shall not be greater than% of the total cross-sectional area of the inner diameter of the pipe, and shall not exceed

3. The inner wire shall be free of joints and kinks. The pipe sleeve shall be used when the pipeline is butted, the bend shall be connected with elbow or tee, and then glued with glue. The presser foot cap shall be used when connecting to the wire box, and the lock interface must be used between the wire pipe and the wire box.
4. High power electrical appliances such as floor heating and air conditioning should be wired separately, and electrical appliances such as refrigerators that are not suitable for frequent power cuts should also be wired separately. These electrical appliances should have separate switches at the main switch (air switch). If you go far away, you can turn off other power supplies, leaving only the refrigerator power on.
5. After the wire passes through the pipe, it is put into the slot and fixed with cement or quick drying powder, that is, several points are selected on a slot for sealing and fixing. When installing the cassette, the wall hole where the cassette is placed should be larger. Cement can be embedded in the gap between the cassette and the wall hole to fix the cassette firmly to prevent loosening in the future.
6. After the wiring is completed, the decoration company must leave a detailed “pipeline diagram”, number the wall, draw the direction and specific position of the wire with a pen, indicate the size from the upper floor to the lower floor and adjacent wall, especially the joint position of the pipeline. With such a detailed, it will be much more convenient to overhaul the ABC Cables in the future.
From the above points, we can know that it is necessary for wires to go through pipes in the process of decorating circuits. Now experienced masters will choose new types of threading appliances for wire threading. It is fast and professional to wear wires with it. Friends who like it might as well try it.

How many rumors do you know about wires and cables?

The rapid development of the Internet age has not only brought convenience to everyone’s life, but also brought new challenges to our social management. In particular, we have seen the rapid spread of rumors. I believe you can distinguish many rumors, but how many rumors about wires and AAAC Cables have you heard? Can you identify it in time?

If the square of the wire is not enough, it will not be qualified?
not always! For many people, this is already a “common sense” existence, but is this really the case? With the improvement of conductor material production process and scientific and technological progress, the advanced production process of oxygen free copper has been widely used. The resistivity of copper conductor material is enough to ensure that the copper wire less than the nominal diameter can meet the requirements of DC resistance of corresponding specifications, while the conductor of wire and cable has strict requirements on the resistivity of conductor, for example, The DC resistance of 25 mm2 copper core conductor specified in the standard at 20 ° is not greater than 0.727 Ω / km (the second stranded conductor), so the conductor is qualified as long as it is not greater than this value.
Flame retardant ABC Cables will not burn?
wrong! Flame retardant of flame-retardant wire and cable refers to that when a wire and cable fire accident occurs, it can block and delay the diffusion and spread of flame along the wire and cable, and minimize the expansion of fire range of wire and cable. This type of cable has the characteristics of self extinguishing after fire. Fire resistant wire and cable refers to that in the case of wire and cable fire accident, the wire and cable product can adhere to the normal operation for a certain time under the condition that the external flame is still burning, maintain the integrity of wire and cable lines and maintain the normal operation of line equipment.
Will wires and cables have radiation?
Wires and cables do have radiation. However, the fact is that all live things have radiation. For example, 220V wires also have radiation, but the radiation is very small and basically negligible. Moreover, the radiation of wires is much lower than that of mobile phones. If you are really afraid of wire radiation, it is recommended to throw away the mobile phones first. If you are afraid of the magnetic field generated by wires and cables and think that the magnetic field will cause any harm to the human body, the geomagnetic field is even more terrible. Therefore, I think that “radiation from wires will damage health” is just groundless, and I think too much.

The thicker the cable insulation, the better?
No, too thick cable insulation will increase the difficulty of AAC Cable laying. At present, cable laying is mainly bridge or through pipe. Now many enterprises are implementing cable requirements, with tight cable requirements and small outer diameter. There can be gaps in the laying process to emit heat energy to ensure that the outer sheath of the cable is not damaged. Otherwise, it will bring some difficulties to the construction unit and cable laying. In summer, the working temperature will rise, and these temperatures will be emitted through the outer protective layer. The thickness of the sheath increases, and the heat energy is difficult to be emitted, which will affect the service life of the cable. Due to the thermal action of PVC, a series of physical and chemical changes will occur in the insulating layer, losing the original excellent performance, resulting in obvious decline in the insulating performance and even short circuit, Therefore, when selecting the cable, the thickness of the cable must be moderate.
The laying of water and electricity shall be horizontal and vertical
unnecessary! Although the water and electricity wires laid horizontally and vertically look very good, there are really many hidden dangers! Firstly, the material cost of the wire pipe is much higher than that of other laying methods. Secondly, because it is 90 degrees horizontally and vertically, it is easy to get stuck when threading the wire in the later stage! So as long as it complies with the specifications, how convenient it is to lay it!

In addition to the above, there are numerous rumors about wires and cables: wires and cables are cheap, so selling cables makes a lot of money; Wires of the same quality can certainly be bought at a cheaper price; The copper conductor used in wires and cables is not so high; Wires and cables will leak electricity in rainy days, which is unsafe.
Although some are rumors, it’s not too much to say that wires and cables are lifelines. We should be more careful when buying. Only by selecting manufacturers, products and national standard products can we use them at ease.