Which is better, copper core or aluminum core?

When it comes to wires and Cables Manufactor, we have to mention the copper and aluminum in their main materials. Then the question comes, what is the difference between copper core and aluminum core wires and cables? Which is better? Let’s get to know about it~


There are several ways to distinguish copper core from aluminum core
First of all, from the model of the wire, the meaning of the letters in the model is as follows: B – fixed laying; X – rubber insulation; L-aluminum core (copper core is not indicated by letters); W-chloroprene sheath; Y-polyethylene sheath. For example: bxw – Copper rubber insulated chloroprene sheathed wire; Blxw — aluminum core rubber insulated chloroprene sheathed wire.
Secondly, it is intuitive to distinguish from the material of wire core. The wire core of copper wire is made of copper, and the wire core of aluminum wire is made of aluminum. Because copper is golden yellow and aluminum is white. You can directly peel a small section of wire core to see the color to distinguish between copper core and aluminum core.
Warm tips: now many aluminum core wires will be coated with a layer of yellow material on the surface of the wire core, commonly known as copper-clad aluminum wire, which also looks yellow. The differences are as follows: first, scrape off the surface, copper wire or yellow, aluminum wire will appear white; The second is to burn with a lighter. The flame of copper core wire is blue, and that of aluminum core wire is white. So we must polish their shining eyes, do not be hoodwinked by unscrupulous business yo~
The difference between aluminum wire and copper wire
1. The cut-off capacity of copper wire is different from that of aluminum wire;
2. Aluminum wire is relatively cheap;
3. The weight of aluminum wire is lighter;
4. The mechanical strength of aluminum wire is poor;
5. The aluminum wire is easy to be oxidized at the end of the connecting wire, and the temperature will rise after oxidation
6. The internal resistance of copper wire is small. Aluminum wire has larger internal resistance than copper wire, but it dissipates heat faster than copper wire. It is mainly due to different current carrying capacity and mechanical strength. So the current carrying capacity of aluminum is about 80% of that of copper. The mechanical strength of copper is much better.
Comparison of advantages and disadvantages between copper wire (cable) and aluminum wire (cable)
The resistivity of copper core is low: the resistivity of aluminum core is about 1.68 times higher than that of copper core;
The copper core has good ductility;
High strength of copper core: the allowable stress at room temperature can reach 20 for copper and 15.6kgt/mm2 for aluminum;
Anti fatigue of copper core: aluminum is easy to break after repeated bending, but copper is not easy to break;
Copper core has good stability and corrosion resistance: copper core is resistant to oxidation and corrosion, while aluminum core is vulnerable to oxidation and corrosion.
Although the aluminum core is relatively cheap, in addition to cheap, in many cases, the rest is chicken feather, especially for some products, we should be more cautious.

Technical problems in power cable insulation detection

1. It is not suitable to adopt AC voltage withstand test, but DC voltage withstand test
High voltage electrical equipment is generally tested by AC withstand voltage test for its main insulation withstand voltage strength, while power cable is often limited by the capacity of test equipment due to its large capacitance, so it is difficult to carry out power frequency AC withstand voltage test. In addition, the AC withstand voltage test may produce free discharge in the hole of oil paper insulated cable and damage the cable. The insulation strength of the cable damaged by the same high AC voltage is much greater than that of DC voltage. Therefore, DC withstand voltage test has become a common method to check the insulation performance of cables. DC withstand voltage test, small equipment capacity, high voltage. Under the action of DC voltage, the voltage in the insulation of the power cable is distributed according to the resistance. When the power cable has defects, the voltage will be mainly applied to the parts related to the defects to make the defects more easily exposed, which can not be achieved by AC withstand voltage test.


2. During DC voltage withstand test, negative polarity connection must be adopted
Generally, when conducting DC withstand voltage test, only pay attention to whether the wiring is correct, and ignore the problem of voltage polarity. The DC breakdown strength of ACSR Cable is related to the voltage polarity. If the cable core is connected to the positive pole, under the action of electric field, the moisture in the cable insulation layer will penetrate and move to the lead skin with weak electric field. As a result, the defects are not easy to find, and the breakdown voltage is 10% higher than that when the cable core is connected to the negative pole. Therefore, the negative connection should be used for DC withstand voltage test of power cable.
3. Influence of temperature on DC withstand voltage test
The insulation resistance of cable decreases with the increase of temperature and increases with the decrease of temperature, just like other high-voltage apparatus; The leakage current increases with the increase of temperature and decreases with the decrease of temperature. It can be seen that temperature has a great influence on the test data. It is very important to convert the test data according to the recorded temperature. If the power cable is cut off for a long time, the actual temperature of the cable should be recorded during the insulation test. The cable test is usually done after several hours of power failure. At this time, the temperature of the cable core is close to the soil temperature. Because the test time is relatively fixed every year, the soil temperature generally has no great difference, but the test data can not be converted according to the recorded outdoor temperature, but should be calculated according to the soil temperature. The temperature of different places is also different. The outdoor temperature of the cable placed in the open air is subject to the outdoor temperature, and the water temperature of the cable placed in the water is subject to the recorded water temperature. For the cable just cut off, the core temperature of the cable should be tested. The voltage distribution between the cable core and the lead sheath depends on the insulation resistance, so the temperature of the cable core and the lead sheath has a great influence on the voltage distribution. When the temperature difference is small, the voltage shared by the insulation near the cable core is higher than that near the lead sheath; If the temperature difference is large, the insulation resistance near the cable core will decrease due to the increase of temperature, and the voltage shared by the insulation resistance near the cable core will decrease, which may be smaller than that near the lead skin. Therefore, it is easy to find the insulation defects near the cable core in the cold state, and it is easy to find the insulation defects near the lead skin in the hot state.


4. During DC withstand voltage test, the cable must be fully discharged
The capacitance of power cable is very large. After DC withstand voltage test, the energy of residual charge is still relatively large, which directly affects the measurement of insulation resistance and absorption ratio. If the discharge time of the cable is short after the first DC withstand voltage test and the residual charge is not discharged completely, the charging current and absorption current will decrease compared with the first time, so the phenomenon of false increase of insulation resistance and decrease of absorption ratio will appear.
In addition, insulation resistance test immediately after DC withstand voltage test will produce false phenomenon of insulation resistance decrease and absorption ratio increase. This is mainly caused by the opposite polarity of the connection voltage of the megohmmeter measuring the insulation resistance and the DC withstand voltage. In the DC withstand voltage test of cable, if the discharge is not sufficient, measure the insulation resistance immediately, then the insulation resistance meter needs to output a lot of charge to neutralize the residual charge in the cable, resulting in false reduction of insulation resistance. Because the DC withstand voltage test time is generally 5min, the discharge time of cable after DC withstand voltage test should be more than 5min. The longer the cable is, the longer the discharge time is. After insulation resistance test, the discharge time is longer than the charging time.
5. During DC withstand voltage test, it must be shielded
When DC withstand voltage and DC leakage tests are carried out on power cables, the stray current caused by equipment has a great influence on the test results because the test voltage is higher and the leakage current of cables with good insulation is smaller. In order to eliminate the influence of stray current on the test results, the microammeter is connected to the high voltage side, and the high voltage lead and the microammeter are shielded. Because the micro ammeter is connected to the high-voltage circuit and the high-voltage lead and micro ammeter are shielded, the influence of the corona of the high-voltage lead and the stray current of the test equipment on the test results can be eliminated, and the accuracy of the test results is high. This kind of wiring can be used for the cable sheath with or without insulation to the ground.


Tuopu electric, a professional manufacturer of DC high-voltage generator, thinks that under harsh environmental conditions, the leakage current on the cable surface is large, so that the test data can not reflect the real situation of insulation. This method can completely eliminate the influence of the surface leakage at both ends of the cable, and can measure the real leakage current data of the cable insulation.

Characteristics and optimization of electric vehicle high voltage cable

The perfect and complex design and use of high-quality materials will result in expensive acsr cable costs. Experience shows that, for specific high voltage cables, it can be tailored by optimizing the cross section, temperature requirements, flexibility and shielding effect. Weight and cost savings can be highlighted, and over sized and over sized components can be avoided.
1. optimization of sectional area and temperature grade
The selection of cables is mostly based on the ambient temperature and the transmission current index. In this regard, the most important features are “cable section” and “heat resistance grade of materials used for cables”.
The voltage drop of the conductor is converted into the conductor of the high voltage cable heated by heat energy. This heat can be partially transferred to the environment, which reduces the operating temperature of the conductor. Lower temperature gradients can transfer less heat. Cables with continuous load current can cause the highest rated temperature to be borne. This temperature can cause the aging of the materials used.


The challenge for cable designers is to design the most suitable cable for application: excessive conductor specifications can lead to increased cost and weight, and larger outer diameter. In the worst case, only considering the highest possible load current and ambient temperature will result in the use of large section cables, high temperature resistant materials such as organic fluorine or silicon.
It is very meaningful to determine the relationship between current and load environment temperature from the technical and economic point of view. The real driver periodic dynamic current peak should be considered, allowing for a reasonable definition of the load current and peak current in the worst case.
A good design prerequisite is an understanding of the basic conditions, such as the need to determine the ambient temperature and cable load first.
Generally, the high-voltage cable manufacturer with large cross-section has a large inertia in terms of temperature change, so the peak current of acceleration or deceleration of vehicles will not cause the influence of a large conductor temperature.
The ability of high voltage cables to handle these peaks is usually defined by thermal overload performance, even if the short-term temperature peaks are allowed to exceed the cable temperature level defined above. Therefore, the cable does not need to be designed as a higher working temperature level, and it is unnecessary to use cables that exceed the specified working temperature.
The permanent load current and single pulse or series pulse can be considered comprehensively, together with various parameters, such as ambient temperature.
The combination of theoretical basis and practical experience can preliminarily determine, select and optimize the high voltage cable which meets the application.


2. flexibility optimization
The available space for the cable routing of the vehicle should be considered carefully. The bending radius of the vehicle in a specific area will lead to the improvement of the flexibility requirements of the whole cable. If small changes may be made in the overall design, it is very meaningful to avoid the problem of tight bending.
Cables do not have to be of the highest flexibility. The exact definition of bending force, combined with the structure and corresponding test equipment, enables the designer of the cable to create the most suitable application design. Especially for larger section cables, it is significant to reduce the cost by replacing the high flexibility design with flexible or conventional structural design.
3. optimization of shielding effect
The shielding effect defined in a certain frequency range is very necessary for the development of cables. Shielding effects without frequency information are not useful, which may lead to excessive size and expensive combination shielding for the solution, which is no longer necessary from a technical point of view.
Generally, the electric vehicle cable development and design stage can be considered by theoretical calculation. Then the shielding effect of high voltage cable is verified by means of test.
Concluding remarks
The high voltage harness of electric vehicle and traditional wiring system still have a long way to go. Specific specification requirements are usually not clearly defined, which can lead to technical complexity, and thus lead to expensive solutions.
All parties involved in the development stage must adopt system oriented method to optimize the technology and cost of high voltage cable reasonably.


These parties may include cable, connector and component suppliers, harness plants, and host plants.
The knowledge accumulation of the whole system and the specification of a high voltage cable which is oriented to the target requirements are the basis of the optimization design.
The R & D Department of cable manufacturing uses theoretical calculation and appropriate measuring equipment to verify that it is capable of developing more suitable cables for application.

Electric vehicle high voltage cable performance requirements and standards

1、 Overview
With the rising of international crude oil price, the whole society pays more attention to the environmental deterioration and global warming, and the tax tilt and policy support of governments, which promotes the market share of alternative energy, especially electric vehicles, to increase all over the world.
Electric vehicles mainly include three types, namely pure electric vehicles, hybrid vehicles and fuel cell vehicles.
Pure electric vehicle and fuel cell vehicle are driven by an electric motor. Hybrid electric vehicles are supported by motors when the efficiency of internal combustion engines is not high under acceleration and low speed conditions.
Their common feature is to use up to 600V or higher drive voltage, involving wiring, they all have the same basic requirements, both in EMI (electromagnetic interference) protection system safe transmission of high current and voltage.
As a high voltage acsr cable, it is used to connect high voltage battery, inverter, air conditioning compressor, three-phase generator and motor to realize the transmission of power and electricity.
The basic principles of electric vehicles seem to be simple. But in-depth analysis, the manufacturers of the system are facing a series of challenges to overcome.
New technical requirements are put forward for the items of high voltage cable, such as flexibility, shielding, safety and size of electric vehicle, because these will affect the wiring of components with high current and high voltage. In the face of different technical points of each possible power system, different special requirements are put forward for the components needed.
It is necessary to note that the high voltage system of electric vehicles is not a typical high-voltage system. The relevant terms such as “high voltage” and “high current” must be limited to the scope of the automotive field, compared with the low-voltage system of conventional vehicles.
In other fields, reference systems adopt totally different standards, such as the definition of high voltage in the power field, which starts at thousands of volts.
2、 Requirements for high voltage cable of electric vehicle
The innovative electric vehicle design presents new challenges to high voltage cables and system components, which cannot fully adopt the existing solutions. The specific requirements are analyzed as follows.
1. voltage
The basic difference between the cable and the conventional vehicle is that the structure needs to be designed at 600 V rated voltage, and if used on commercial vehicles and buses, the rated voltage can be up to 1000 V. By contrast, it’s even higher. The cables used in vehicles powered by internal combustion engines are designed to have a rated voltage of 60 v.
Power generated by the system (P = u × 1) The high voltage can reduce the power loss in the transmission system (pls= I2) without change due to the use of lower current × R)2. current
Because the cables connect the battery, inverter and motor, the high voltage cable needs to transmit high current. According to the power requirements of system components, the current can reach 250A to 450A. It is difficult to find such a high current in conventional drive vehicles.

3. Temperature
The result of high current transmission results in high power consumption and heating of components. Therefore, the high voltage cable is designed to bear higher temperature. At present, it can be seen that there is a trend of further increase in temperature requirements.
In contrast, the current vehicle usually uses a cable rated at 105 ° C, as long as it is not used in the engine compartment or other areas with high temperature resistance. High voltage cables of electric vehicles are usually higher than this temperature, such as 125 ℃ or 150 ℃.
If the routing in electric vehicles is unfavorable, the host plant will even put forward higher requirements for high temperature resistance. Such as exhaust pipe, motor front, battery back, etc.
4. working life
The automotive industry usually has a design life of 3000 hours for cables of specified temperature grade. In recognized cable standards (e.g. ISO 6722, ISO 14572), this value is usually used for long-term aging tests. The special requirements of customers in high voltage applications may exceed 3000 hours, and the cumulative operating time at the specified temperature can reach 12000 hours.
5. shielding effect
The high voltage aaac cable itself does not need to be shielded, because it does not transmit data as coaxial cable, but it is necessary to prevent or reduce the high frequency radiation generated by switching power supply in the system to be induced to the surrounding parts through the cable.
Unlike fuel driven vehicles, it is necessary to control the three-phase alternating current of the motor of the electric vehicle. The sinusoidal voltage with energy is equivalent to the square wave pulse signal with different frequencies. Because of the steep edge of high frequency pulse, it will generate strong energy harmonic emission to the surrounding area.
EMI problem can be solved by using appropriate shielding method. In some cases, different shielding types are needed to meet different requirements of shielding effect.
6. flexibility
The challenge for the development of hybrid vehicles in many cases is that the existing series of platforms originally designed only to load gasoline engines and its components into more electrical components. Even if wiring is not considered, the space constraints can be predicted.
In addition, space is required for cables and connectors to pass through routing. The usual consequence is the bending radius that leads to tension.
Because of the inherent design of conventional cables, high bending force is difficult to overcome. In order to solve this problem, high flexibility and toughness of high voltage cable is very important. Only flexible design can be easily realized through vehicle routing.
7. bending resistance
If the motor is located near the moving part of the vehicle and then causes continuous vibration of the connected high voltage cable, it requires that it be designed to withstand high cyclic bending to ensure good bending endurance.
8. identification
Because of the increased application risk caused by high voltage, various standards define that high voltage cables must be visually different from ordinary vehicle cables, and the designated surface must be bright orange.
Warning content and special marks can also be printed, such as “caution! High voltage 600V “, high voltage lightning sign, etc.
3、 The standardization status of electric vehicle cable
In view of the challenges and requirements of the high voltage cables used in the electric vehicle, it is necessary to establish new cable standards to meet the needs of suppliers, harness plants and host plants.
The international organization for Standardization (iso/tc 22/sc 3/wg4) of the electrical and electronic sub Technical Committee of the Technical Committee on road vehicles of the international organization for standardization is carrying out this work.
As can be seen on ISO 6722, revisions have been made based on the common 60 V cable standards to meet the requirements of 600V cables. Because most of its requirements are still very common, but often do not consider the special design of high voltage cable. Similar revisions have been made to ISO 14572.
At present, standardization of high voltage cable with voltage higher than 600V is a task of each working group. The standard number is ISO 17195.
SAE will adjust the current high voltage (600 V rating) specification SAE j1654 requirements for high voltage cables and cover rated voltages from 600 to 1000 V. The newly created standard SAE j2840 will be defined as shielded type cables.
LV is a common purchasing specification of five major German auto companies. At present, LV 216 is a high voltage cable standard for electric vehicles with rated voltage of 600 v. It covers shielded cables with single core and multi-core.
The national automobile industry standard of high voltage shielded cable in China is under development, and its rated voltage will reach 1000 V.
4、 The structure design of high voltage cable for electric vehicle
Standard products and very specific requirements are difficult to define. The purpose of this paper is to solve the basic design ideas and overcome the challenges mentioned above by applying advanced high voltage cable structure principle.


1. conductor design
The flexibility of high voltage cable is mostly determined by the design of conductor. That’s why high voltage cables use special conductors with a large number of very small diameter monofilament. A certain number of single wires are twisted first, then concentric rewind is carried out to form the soft conductor required by high voltage cable.
Another advantage of the number of roots is better bending resistance. The short pitch of the strand can also improve the bending life of the high voltage cable.
2. insulation materials
The selection of insulation materials mainly considers the heat resistance requirements and mechanical strength. Compared with the standard battery cable, the soft materials can be selected reasonably to keep the specially designed stranded conductor flexible.
3. cable formation
When the cable is multi-core, it is usually necessary to twist the core. In order to make up for the deformation caused by the twisted high voltage cable core, the so-called twisted special equipment is needed. In this process, the special strand machine is equipped with a set-up plate which rotates in reverse direction relative to the direction of stranding. This is necessary to prevent the deformation tension of the cable.
According to the structure of cable, filling is usually used to ensure the high concentricity of shielded cable, and finally to obtain a satisfactory high voltage cable. The use of wrapping tape in the stranded cable core can keep the cable flexible.
4. shielding
Due to EMC requirements, the braided shielding is made up of several copper wires. Tin plated copper wire can make it more powerful to resist environmental effects such as oxidation. The design is flexible with fine copper wire
Shielding requires a coverage of more than 90% to overcome the EMI problem described earlier.
Different shielding effects need, woven shielding can be combined with other shielding, such as aluminum plastic to meet the film. The shield can be wrapped with a layer of non-woven fabric to ensure that the sheath is easily peeled off during assembly.
5. sheath
As with the insulation of the core, the sheath material is selected according to the requirements of heat and mechanical properties. Environmental properties such as resistance to liquids and wear are also important for sheath due to direct contact. These characteristics are mainly determined by the type of sheath material selected, and to some extent, are affected by the design of sheath structure.
If special requirements, such as overcoming the wear of the installation vehicle environment, require increased wear resistance, this should be considered when selecting materials. Usually, test equipment is used to simulate the reality to verify these characteristics.
Choosing a softer material benefits from flexibility, which can lead to lower wear resistance of high voltage cables.
The extruded jacket shall be a bright orange as specified in the relevant specifications and special high pressure warning marks can be added as specified.

Today’s copper price and market analysis

Today’s copper price
CCMN spot copper price: 71930 yuan / ton, down 400 yuan / ton

Mine end plans to expand production, copper may fall on the 26th
Abstract: China increased price control and continued to exert pressure. The copper price fell by 48 US dollars overnight. Large copper producers plan to expand production. Recently, downstream copper processing enterprises are under pressure. Today, copper materials are falling.
[copper futures market] China increased commodity price regulation and continued to put pressure on the market. The copper price fell sharply overnight. The latest closing quotation was US $9935 / T, down 48, or 0.48%. The trading volume was 12258, increasing 981, and the position was 311989, increasing 223. In the evening, Shanghai copper fluctuated at a low level. The latest closing price of the main monthly 2107 contract was 71780 yuan / ton, down 560 yuan, or 0.77%.
London Metal Exchange (LME) reported its latest inventory of 125925 tons on May 25, up 100 tons or 0.08% from the previous trading day.
BHP Billiton, Glencore and other large copper producers have proposed to expand production plans, and the tight situation at the ore end is expected to gradually ease; Recently, the price has come down, but it is still at a high level. The downstream copper processing enterprises are under pressure, while the refined copper output and scrap copper import are growing steadily. The spot copper price is expected to fall today.

Henan Huaxing wire and cable Co., Ltd. has a complete quality control system and advanced laboratory equipment to ensure that every product wholesale to customers meets the quality requirements. At the same time, we accept the testing requirements of customers and third-party testing institutions.

Up 80%! Some people “cover” copper not sold

“Do you have a copper machine tool? We can make a home valuation! ” Lao Zhao is a recycling business of scrap metals. Recently, he is circulating recycling advertisements by friends.
After the Spring Festival, copper prices have set a high, recycling manufacturers are looking for scrap copper. Zhao also took the opportunity to make a profit in this wave of market. He said that before the Spring Festival, the price of copper acsr cable was about 40000 yuan per ton, and now it has risen to more than 70000 yuan a ton, or nearly 80 percent.


With the continuous increase of copper price, the raw material cost pressure of downstream metallurgical and processing enterprises is becoming increasingly prominent. In this context, relatively low-cost and environmental protection of waste copper has become “fragrant bun”.
Industry insiders said that the rising copper price and the increase of copper cost are the main reasons for the popularity of recycled copper resources. In the future, the depletion and supply reduction of copper resources abroad will be the trend of the whole world. The market of urban mines and recycled copper resources will have unlimited potential.

01
Downstream telephone burst, waste copper recycling station “cover not sell”

Near a scrap metal recycling station in the suburb of Tanggu, Tianjin, the abandoned copper wires were piled on the roadside, and the sun was golden. Once, this is the “urban waste” that nobody asks for. Nowadays, they are precious renewable resources that enterprises plunder.
In the warehouse built up by color steel plate, Shanghai Securities News reporter saw that the door was a black and abandoned cable, which was randomly collected by several sacks. Walk down the wall, and the white sack behind it is filled with yellow copper cables. The staff said that these are copper wires picked up from the cable at the door. Once, these copper wires were not worth a few money, and now they are worth a lot.

“We have been operating this recycling station for more than ten years, and this year’s good market has hardly seen.” Lao Qin, the head of the recycling station, said that the scrap copper sold only 40000 per ton a ton a ton a year ago, but there was not much downstream goods, and the warehouse was filled with goods that could not be sold. After the Spring Festival, copper and brass cables suddenly became “fragrant bun”, which has exceeded 80000 yuan per ton.
In the past, recyclers were “unreasonable” about copper waste resources, waiting for customers to ask for the recovery price. Now they are starting to drive to factories around the country to find copper scrap valuations.
The copper recovered by Laozhao in Shanghai comes from the abandoned machine tools, cables, copper pots, and parts removed from various old appliances. He took his recycling company for example, in the past, after he recycled and processed it every month, copper sold at most 12000 yuan, and now it can reach more than 100000 yuan per month“ Taking advantage of the high copper prices in recent months, I have shipped all the hoards that I couldn’t sell in the past, making a lot of money net. ”

However, more copper recyclers have a “business experience” and do not rush to sell the accumulated copper to intermediate agents or downstream copper refineries.
“Copper is now priced one day, and the cable copper, which was once slow to sell after the Spring Festival, is almost double.” Old Meng, boss of the scrap metal recycling base from Foshan, said.
Old mengning can backlog some scrap copper, and sell them together when prices are higher. The recyclers around him also sniffed business opportunities. Although agents and middlemen called to order goods every day, they still covered the scrap copper in their hands.
Such “business” also sinks to the basic environmental sanitation workers. According to a big data service provider for waste products in Chengdu, at present, many environmental sanitation workers in Chengdu will consciously look for copper containing cans and electronic components, “the items were sold for a maximum of 1200 yuan a day before, and now they can sell threeorfour yuan or more.”
Although the price of scrap copper has risen greatly, the sales profit of different recycling stations is quite different. Shanghai Securities News reporter understands that compared with the previous year, the most of them have reached several times or even ten times, while the few are only 30%. According to zz91 regeneration network data, as of the 12th, the average price of main copper scrap in Jiangsu, Zhejiang and Shanghai was about 65000 yuan / ton, up 32% from the beginning of the year.
In response, Wu Xinyong, an analyst in the copper industry of Shanghai Nonferrous network, said the main factors determining the profit of scrap copper recovery are the recovery cost when recycling and the price difference before the delivery price at the time of sale. If the scrap copper is recovered at the low point of copper price before the year ago and sold at the current copper price high, the intermediate profit will be considerable.

02
“Price difference between refined waste” and the economy of waste copper are highlighted

As for the phenomenon of copper scrap is tight since this year, Wang siran, director of Ping An Futures Research Institute, told Shanghai Securities News that in practice, many products of copper processing enterprises can take refined copper as raw materials and scrap copper as raw materials. There is a price difference between scrap copper and refined copper, and the price of scrap copper is not as fast as that of refined copper.
Wei Lai, director of all color research of Tianfeng futures research, told Shanghai Securities News that since this year, downstream enterprises have been in stable demand for copper, especially in emerging fields such as new energy vehicles, electronics, home appliances and other industries, with higher demand for copper. With the continuous increase of international copper price, the economy of waste copper has been highlighted. Because of the excessive cost of using refined copper, processing and smelting enterprises tend to increase the consumption of waste copper.
“The supply of copper concentrate abroad is relatively tight this year, and there are epidemic and strike in the main production areas of copper concentrate such as Chile.” Wei Lai said.
In March, copper production in Chile has fallen for 10 consecutive months, according to data. According to the National Bureau of statistics, Chile’s copper production in the first quarter of 2021 was 1.4 million tons. The year-on-year decrease was 2.2%.
The decline in copper production has shifted some demand to scrap copper, which also promotes domestic imports of scrap copper. My non-ferrous network data show that, due to steady growth of downstream demand, the import of recycled copper has increased significantly since this year. In the first quarter of 2021, the import of recycled copper was 363700 tons, an increase of 73.39% year-on-year.
“The use of scrap copper is no longer new. The industry has mature technology to convert waste copper into refined copper. From the perspective of environmental protection and carbon neutralization, it is also in line with the trend to increase the use of waste copper. ” Wei Lai said.

Advantages of environmental protection cable

Compared with ordinary aac cables, environment-friendly cables have the following advantages:
The first is that it has high flame retardancy. As we all know, the flame retardancy of cables is very important. For cables with safety and fire protection requirements, cables are not easy to burn and fire, and can prevent the expansion of flame.


The second is halogen-free, green insulation, special oxygen barrier material, which not only has good electrical and mechanical properties, but also ensures that the product does not contain halogen, so as to prevent the formation of traditional PVC wires in the combustion process and produce carcinogenic dioxin materials, so as to prevent secondary pollution.


The third is no peculiar smell and corrosive smell, no hydrochloric acid and other toxic gases, no pollution to the environment, the production of new environmental protection coating wire and cable material, the use process and combustion will not produce or very little discharge of acid gas, ensure the safety of personnel and reduce equipment damage and other environmental protection features.


The fourth is the high light transmittance. The smoke generated by the burning of environment-friendly cables is very thin, which is conducive to evacuation and fire fighting. The light transmittance of the product is more than 40%, much higher than that of the traditional flame retardant cable, and lower than 20% or even higher.


The last one is the waterproof and anti ultraviolet performance of the environmental protection cable, and the special molecular structure of the environmental protection wire and cable to ensure the manufacture of ultra-low water absorption green environmental protection materials. The special ultraviolet absorber makes the product have good anti ultraviolet performance.


Henan Huaxing wire and cable Co., Ltd. is an old cable manufacturer with 37 years of experience. In terms of operation, State Grid cable group always adheres to its original intention, makes products down-to-earth and conducts research and development conscientiously. Strengthen credit, cooperate for development, and win the future with quality.

Cable enterprises should start from small things to ensure safe production

A general manager from a well-known abc cable company publicly told his views on safety production. He said that an employee accidentally fell down at the production site and caused serious injury. The fall was caused by a pool of oil on the ground. The reason why there is oil on the ground of the production site is that the operator of a certain machine is busy with starting the machine just after cleaning the mold, and the oil on the ground has not been cleaned up in time. So a major safety accident happened in an instant. The probability of a major safety accident caused by a pool of oil is very small, but it did happen“ Small things “,” small probability “and” small mistakes “often hide huge crises. If we do not pay attention to these “little things”, do not want to do a good job in the details of “small things”, do not take “small things” seriously and take them lightly, the “small things” will eventually lead to “catastrophe”. If the operators had cleaned up the oil on the ground in time, this major safety accident could have been avoided.


Accidents often happen in a moment, but it is a long process to cultivate the good habits of employees and grasp some details in safety production. Safety in production lies not in saying well, but in doing well, not in how much is right, but in not doing anything wrong. Good habits are the basis of safety work. In the factory, what kind of thinking employees have, there will be what kind of behavior; What kind of behavior will lead to what kind of result.
In daily safety management, knowledge and methods can only solve specific problems in one move, but good habits can change a person or a group of people. Practice has proved that in addition to a thick system and measures, some formal slogans and slogans, and the inspection and supervision of actions, it is more important to continuously strengthen the education of employees and keep them in mind all the time, And the possible accidents in advance prevention, vigilance protection, safety production will be solid.


There is a famous “Hain rule” that says: behind every serious accident, there must be 29 minor accidents, 300 near miss omens and 1000 potential accidents. The occurrence of any accident has a certain aura and a gradual process. Responsibility determines safety. Only when we weave several lightning protection nets and firewalls with our heart and mind and love, and deepen safety responsibility into a good habit, can we be prepared and take precautions.
Good safety habits are: work hard, is responsible, pragmatic spirit, to do every thing in every day; Working hard means not letting go of every detail in the work, and being able to actively see through the potential problems behind the details; Work hard, is to make ourselves better than in the past, better than others, let us win the safety of every moment with every minute of our heart.

Composition of flexible mineral insulated cable (bbtrz)

Flexible mineral insulated acsr cable is composed of copper strand, mineral compound insulation and mineral compound sheath. It adopts flexible structure, and the main materials are inorganic materials, which make up for the defects of hard structure, easy to burn and toxic. It also has some advantages that other cables can not have, such as: fire resistance, high load flow, impact voltage resistance, mechanical damage resistance, halogen-free, non-toxic, explosion-proof, waterproof, corrosion-resistant, long life, safety, overload resistance, high temperature resistance and low cost.


The flexible mineral insulated cable (bbtrz) has the characteristics of general products. Because the insulation is made of organic polymer, it is easy to carbonize and lose its insulation function under the condition of flame. Because the main materials of flexible mineral insulated fire-proof cable (bbtrz) are composed of mineral compounds, it will not cause fire itself, and it is impossible to burn or support combustion. These materials generally have a high melting point of more than 1500 ℃, so fire-proof cable can play a normal transmission function even when used in flame condition, which is a kind of fire-proof cable in the real sense.
The process structure of the flexible mineral insulated fire-proof cable (bbtrz) is identical with the traditional cable. It successfully solves many shortcomings of the products determined by the production process of the bttz.
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Advantages summary:
1. It is really flexible, and the structure is as soft as the ordinary aaac cable.
2. The process structure is the same as that of ordinary cable, and the theoretical production is infinite, and one cable can be produced with fixed length
3. The installation is without joint, the construction is simple, the reliability is improved and the cost of investment is reduced.
4. The multi-core can produce 300mm2, overcome the shortage of single core with rigid bttz of 25mm2 or more. 5. The cable can be reused if the line is reconstructed and adjusted.
Characteristics of flexible mineral insulated cables
1. improve the insulation stability: not only the fire resistance of rigid mineral insulated cable is retained, but also the characteristics of not suitable for moisture absorption, so the insulation is more stable.
2. the voltage resistance level is improved: the voltage withstand level can reach 1000V, which reduces the impact voltage caused by the frequent start of inductor and frequency converter, and correspondingly improves the service life of the line system.


3. full series: it can be processed into single core or multi-core structure according to the actual needs of users, and can achieve 96 cores at most, covering almost all kinds of building cable requirements of power cable and control cable.
4. no intermediate joint: mature strand and cable forming technology are adopted, which can be produced according to the user requirements, not only reducing the cost of joint, but also improving and realizing the whole line consistency.
5. flexible and easy to install: because of the traditional cable structure such as strand and cable forming, the cable is softer, and it is more convenient to install and lay because of the need for special terminal joint.
6. space saving: because of the multi-core cable with large section and large length, unnecessary waste of laying space caused by multiple arrangement and intermediate joints is avoided.
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7. public welfare: due to the improvement of structure, a large number of minerals and mineral compounds are used, which not only saves copper, magnesium and other resources, but also saves a lot of energy consumption correspondingly. The public welfare value is also very significant.
Installation and laying of flexible mineral cable
When cables are laid in open, cable supports, hooks or metal ropes shall be used along the whole length. The maximum span shall meet the following requirements:
1. meet the bearing capacity of support parts, the outer layer of the non-destructive cable and its cable core;
2. make sure the cables can be arranged neatly with each other;
3. adapt to the layout requirements under working conditions
Flexible mineral insulated fire-proof cable can ensure emergency use after installation. It can also be used as halogen-free flame retardant cable and fire-resistant cable with temperature resistance of 125 ℃ at ordinary times. Because of its wide coverage, it overcomes the defects of rigid Mi cable, plays the advantages of flexible Mi cable, and provides practical products for key projects, especially in the application of super high-rise buildings, It makes people’s life and property security guaranteed reliably, and promotes the broad development of their industry.

Is the diameter of copper wire less than the national standard a non-standard cable?

For a long time, there is a headache for aaac cable sales, that is, whether the loss of square cable is non-standard cable. Because many customers like to measure the diameter of cable conductor, it can be used to determine whether the cable is qualified. So many people discuss, is copper wire diameter smaller than national standard calculate non-standard?
Recently, a report issued by CQC, an authoritative organization, attracted the attention of the industry. This report also answers the problem that bothers many people. With this report, you sales owners can explain this to the customers.

What organization is CQC?


CQC is a national certification institution approved by the central organization preparation committee and established by the State Administration of quality supervision, inspection and quarantine and entrusted to the state accreditation and supervision commission. CQC is the earliest, largest and authoritative certification institution in China to carry out quality certification. In recent decades, CQC has accumulated rich international quality certification experience, and has achieved outstanding achievements in various businesses. The number of certified customers ranks first in the national certification organization and the top of the global certification organization.
The above introduction is extracted from Baidu Encyclopedia, and you can find it by yourself( Learn more cable technology, please click here, mass dry goods wait for you) after a simple introduction, we believe that CQC’s report is authoritative. Let’s go to the topic below to see what this report explains.
[nominal] cross section of cable conductor
Nominal sectional area: refers to the quantity value specified in the product standard and is often used in the table. The quantity value extended from the nominal value shall be generally tested by measurement under the specified tolerance.
From this concept, we can know that this nominal cross-sectional area is only used to describe the specifications of wires and cables, but only the code or name of the specification, which is convenient for production management and document representation.
The actual cross-section area of cable conductor
Actual cross-section: it refers to the actual cross-sectional area of the conductor, which is the value measured by micrometer. For the manufacturers of wires and cables, the design of conductor section of a nominal section can meet the standard requirements. It means that the design section (electrical section) under this nominal section shall meet the standard requirements, namely whether the DC resistance meets the standard requirements.
With the improvement of the production technology and the progress of science and technology, the advanced production technology of oxygen free copper has been widely used. The resistivity of copper conductor material is enough to ensure that the DC resistance of corresponding specification can be met with copper wire less than the nominal diameter.
In summary, the phenomenon that DC resistance is qualified in cable industry is generally found, but the actual diameter of the core is smaller than the nominal diameter or the actual section is smaller than the nominal section, which is in line with the requirements of product standards.


Requirements for conductor cross-section area in the standard
At present, the product standards of major mainstream standard systems of wires and cables adopt nominal sectional area or specification code to distinguish conductors with different sections. For example, IEC standard, European standard and national standard (gb/t5023, gb/t12706, etc.).
Among them, the evaluation of different section specifications and codes is required by the conductor resistance value, rather than the actual measurement of conductor cross-section area.
In the national standards gb/t 5023-2008, gb/t 5013-2008 and gb/t 12706-2008, the main provisions of cable conductor are in accordance with the requirements of gb/t3956.
The main assessment includes:
(1) The maximum diameter of single line of soft conductor and the minimum number of single wire in hard conductor;
(2) Resistance of conductor at 20 ℃.
Above is our simple interpretation of this report. After you have read it, you will know whether the cable is qualified is not determined by its cross-sectional area, but resistance. If you have such a dispute again, you should show him this article and correct the incorrect idea together.