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.

Analyze the development opportunities of cable accessories industry

1. Market demand
China’s power grid construction investment will continue to grow steadily, including smart grid construction, new energy construction and distribution network transformation, which will bring a new round of development opportunities for the cable accessories industry.


The “long-distance, large-scale, high-capacity and high-voltage” pattern of power grid construction will further stimulate the demand for high-voltage and EHV cables and ABC Cable accessories. At the same time, with the development of new energy such as photovoltaic, wind power and nuclear power, the demand for high-voltage and ultra-high voltage DC cable accessories will also increase significantly. Among them, offshore wind power has become a research hotspot of global wind power development. All countries in the world regard offshore wind power as an important direction of renewable energy development, and China has also classified it as an important part of strategic emerging industries. China’s offshore wind power development has entered the stage of large-scale and commercial development. Therefore, it also brings opportunities for the development of submarine cable accessories (submarine cable terminals, intermediate joints and repair joints).
At present, China’s cable accessories industry is still dominated by the domestic market to meet domestic demand. Because Chinese products are competitive with imported products in cost and price. Along with one belt, one road construction will promote the rapid development of the regional economy along the line, and the demand for power construction will be sustained. One belt, one road, China’s home appliances network is relatively backward. In addition, China’s local equipment companies are backward in technology, limited in supply capacity and high in import dependence. This brings considerable business opportunities to China’s cable accessories enterprises with superior price performance.
In the next five years, the average growth of medium and low voltage power cables for power grid construction will still be 7% – 10%. High voltage ACAR Cable accessories of 66kV and above will also become the growth highlight of the industry.


2. Technological innovation and existing problems
The development of cable accessories is closely related to the development of cables. It has also experienced the process from oil filled insulation to dry insulation, from medium voltage to high voltage and ultra-high voltage. The development and production of cable accessories is not a single professional technology, but requires the use of multi-disciplinary comprehensive technology. The fields involved mainly include electrical, mechanical, chemical, polymer materials, etc.
Chinese enterprises lack the core technology of power cable accessories, especially in the research and development of EHV power cable accessories, which has been restricted by technology. In recent years, the cable accessories independently developed by a few domestic technology leading enterprises have gradually become mature, which not only fill the domestic gap and break the foreign monopoly, but also some products have been exported abroad, and the voltage level has reached 500kV. The quality and reliability of domestic cable accessories have also been greatly improved.
Except for a few leading enterprises, the main products of most domestic cable accessories manufacturers are medium and low voltage cable accessories or fittings. Most of them have small production scale, relatively little R & D investment, weak R & D ability, forward-looking and basic common technology research lags behind foreign competitors, and the development of basic materials, basic processes and key components lags behind. Especially in terms of high-voltage, ultra-high voltage AAAC Cable accessories and special cable accessories, there is still a certain gap with the foreign advanced level. There is a long-term shortage of high-quality talents in the industry, the R & D and test ability is weak, and there are few production enterprises with sustainable innovation ability in the industry.
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Why are mineral insulated cables so hot?

In recent years, the city has developed rapidly
Subway, station, hospital, school, high-rise residence
Expansion of public facilities construction scale
The number of high-rise buildings surged
The demand for urban electricity is rising
Such a densely populated key area
In case of fire, the consequences are serious
In recent years, the fire spread trend in such places shows a similar pattern

According to the analysis of construction safety and fire protection experts
At present, there are still many cables selected for public facilities
No fire resistance
It is difficult to play its due role in fire
The law expressly stipulates that China’s civil construction law stipulates that in the code for fire protection design of construction projects, the fire protection system needs to use mineral insulated cables in order to pass the fire protection acceptance.
Under fire conditions, mineral insulated AAAC Cable can not only ensure the fire power supply within the fire duration (more than 180 minutes), but also will not delay combustion, produce smoke and secondary disasters, so as to win valuable time for fire rescue.
It can be said that mineral insulated cable is a special cable that must be used for fire protection in national important facility construction, large public areas, high-rise buildings and other places. Its fire resistance, durability, safety, reliability and economy can not be replaced by traditional power cable.
1、 Mineral insulated cable structure
Chengtiantai mineral insulated cable is a kind of cable that uses copper sheath to wrap copper conductor core wire and magnesium oxide powder as inorganic insulating material to isolate conductor and sheath (outer sheath is optional), forming a close whole with metal core and sheath.
Magnesium oxide is also a non combustible material, and will not produce toxic smoke or other harmful substances when encountering high temperature. Therefore, the cable with magnesium oxide as the insulator of copper core and copper sheath has good performance and many advantages.
2、 Performance and advantages of mineral insulated ACSR Cable
Chengtiantai mineral insulated cable mainly includes bbtrz (flexible mineral insulated fireproof cable) and yttw (flexible inorganic mineral insulated cable) series. It has the characteristics of good fire resistance, high temperature resistance, large current carrying capacity, waterproof, corrosion resistance, mechanical damage resistance, radiation resistance, electromagnetic compatibility and elegant appearance. At the same time, the cable will not emit any smoke under fire conditions Halogen and toxic and harmful gases.


1. Fire performance
Because mineral cables are all composed of inorganic substances, they will not cause fire, can not burn or support combustion, and will not produce toxic gases. Even if there is external flame combustion, the cable can still work normally. Mineral insulated cable is insulated with magnesium oxide, and the melting point of magnesium oxide is as high as 2800 ℃, which is difficult to burn easily. Therefore, the fire resistance of mineral insulated cable is excellent.
The test shows that the mineral insulated cable can run normally after burning in the flame with the temperature up to 800 ℃ – 900 ℃ for 2h; After burning under 1000 ℃ flame for 30 min, the cable is still intact and continues to operate normally.
2. High temperature resistant operation, large current carrying capacity
The normal service temperature of mineral insulated ACAR Cable can reach 250 ℃. Under special circumstances, the cable can maintain operation for a short time at a temperature close to the melting point of copper sheath. It is very suitable for laying in high temperature places, such as metallurgy, boiler, glass furnace, blast furnace and so on.
Its cut-off flow is much higher than that of other cables. Because magnesia powder has a better conductor coefficient than plastic, the cut-off flow is greater at the same working temperature. For lines above 16mm, one section can be reduced, and two sections can be reduced where people are not allowed to touch.
3. Waterproof, explosion-proof, high mechanical strength
The insulating layer of mineral insulated cable is processed by high-density compaction process, and then protected by seamless copper sheath. In the product standard, it must meet the three requirements of fire resistance, spray resistance and mechanical impact, and can withstand severe impact and mechanical damage. Therefore, it can not only prevent the infringement of water, moisture, oil and some chemical substances, but also apply to the connection of various explosion-proof equipment and equipment in places with explosion risk.
4. Overload protection
When the line is overloaded, the plastic cable will cause insulation heating or breakdown due to overcurrent or overvoltage. For mineral insulated cables, as long as the heating cannot reach the melting point temperature of copper, the cable will not be damaged. Even if the breakdown occurs instantaneously, the magnesium oxide at the breakdown point will not form carbide at high temperature. After the overload is cleared, the cable performance will not change and can still continue to be used normally.


5. The service life is longer and more safe and reliable
Since the structure of mineral insulated cable is composed of copper core and insulating sheath, which is a closed whole, it is difficult for the material to be aged due to the action of oxygen in the external air, which makes the overall service life of the cable longer (2-3 times the service life of ordinary cables). In addition, the characteristics of the copper sheath make the grounding of the cable better, Therefore, lightning protection and grounding measures are effectively realized, so as to ensure the safe and reliable operation of electrical lines.
Due to many excellent characteristics of mineral insulated cables, they have been successively adopted by many domestic electrical design codes or standards in recent years, and also used in many engineering projects in different industries. It can be expected that the use of mineral insulated cables in China will increase significantly in the next decade.

Simple repair method after cable line failure?

After the cable line breaks down (including the breakdown during preventive test), it must be repaired immediately to avoid a large amount of water invading and expanding the scope of damage.
The elimination of faults must be thorough and clean. Otherwise, although it can be used after repair, it will still cause faults in the future, resulting in repeated repair and greater losses.
to repair the fault, the damp part of the ACSR Cable must be removed, and the insulating agent or insulating layer must be checked for carbonization. This paper introduces several simple fault repair methods.

(1) single phase grounding of cable line (without tripping): the conductor damage caused by this kind of fault cable may be local. If it is a mechanical damage, only the AAC Cable insulation is damaged, the conductor is slightly singed, and the land near the fault point is relatively dry, it can generally be repaired locally. The cable core can not be sawed off, only the damaged part of the conductor can be treated smoothly, and the insulation can be wrapped and sealed.
(2) breakdown of cable joint in preventive test: because the voltage of preventive test is high and the insulation strength of the joint decreases gradually during operation, such faults often do not make the ACAR Cable subject to water intrusion. In this case, the connector can be disassembled to check whether the cable conductor is intact and whether the insulation is damp. Check 1 ~ 2 layers of insulating paper on the peelable surface of the oil paper cable, wash with hot oil, and completely remove the moisture if any.


(3) if the indoor cable terminal is broken down in the pre-test, it can also be disassembled and partially repaired. The process is similar to reinstallation, but requires moisture removal. Generally, there is some residual wire left at the terminal part, so the sheath can be appropriately cut for another section, and the operation is more convenient than dismantling the joint.

How to skillfully use aluminum alloy cable in photovoltaic system?

The cost of control system is very important in the era of photovoltaic affordable Internet access. Over the past decade, the price of modules and inverters has decreased by 90%, which has made a great contribution to the overall cost reduction of photovoltaic system, but the cost of cables has not decreased. In large projects, the proportion of cables in the system reaches 10%, which is higher than that of inverters. In fact, as long as the design and installation are proper, on the premise of ensuring the normal operation and safety of the system, some AC cables adopt aluminum alloy cables, which can reduce some costs.
The cables of photovoltaic power station are divided into DC cables and AC cables. The DC cables between components and between components and inverter are generally required to use photovoltaic special DC cables, while the cables from inverter to AC distribution cabinet and from distribution cabinet to transformer are not required to use any ACSR Cables.


What is aluminum alloy cable: aluminum alloy cable is a new material power cable with aa8030 series aluminum alloy material as conductor. The resistivity of aluminum alloy is between aluminum and copper, higher than copper and slightly lower than aluminum. Under the premise of the same current carrying capacity, the weight of aluminum alloy conductor with the same length is only half of that of copper.
When the cross-sectional area of aluminum alloy conductor is 1.5 times that of copper, aluminum alloy ACSR Cable and copper cable achieve the same current carrying capacity, resistance and line loss.
Service life: different metal oxides are formed after the metal surface reacts with oxygen. Aluminum oxide can form a dense surface protective film with a certain hardness. Copper oxide, commonly known as copper green, is a toxic substance between the above two.
Economically, this is the most important aspect. The cost of aluminum alloy cable is about 25% ~ 50% of that of copper core cable. The cost advantage of aluminum alloy cable is relatively large. We can make a comparison. In a 400KW village level poverty alleviation power station, the distance from the AC distribution cabinet to the step-up transformer is 1500 meters, and the maximum output current of the 400KW power station is 580A. If copper cables are used, two 150 square meters are required for each phase and six for three phases, with a total length of 9000 meters and a price of 864000; If you use two 240 square meters of aluminum alloy, the total length is 9000 meters, and the price is 450000 yuan, 414000 yuan can be saved, and the loss of 240 square meters of aluminum wire is lower than that of 150 square meters of copper wire.


There is also a rare earth aluminum alloy cable, which is made of high elongation aluminum alloy material. By adding rare earth trace element materials such as boron to pure aluminum and treated by rolling technology and special annealing process, the cable has good flexibility. When its surface is in contact with air, it can form a thin and firm oxide layer, which can withstand all kinds of corrosion. Even when overloaded or overheated for a long time, it can ensure the stability of the connection, and the cost is about 10% higher than that of ordinary aluminum alloy cable.
Application scope of aluminum cable: aluminum cable can be considered for long-distance overhead line, underground cable trench with large space and places with reliable fixed bridge.
Precautions for use of aluminum cable:
The melting point of copper is 1080 ℃, while that of aluminum and aluminum alloy is 660 ℃, so copper conductor is a better choice for fire-resistant cable. At present, some aluminum alloy AAC Cable manufacturers claim that they can produce fire-resistant aluminum alloy cables and have passed the relevant national standard tests, but there is no difference between aluminum alloy cables and aluminum cables. If they are in the fire center, that is, when the temperature is higher than the melting point of aluminum alloy and aluminum cables, no matter what heat insulation measures are taken, the cables will melt in a very short time and lose their conductive function, Therefore, aluminum alloy should not be used as fire-resistant cable conductor, nor in densely populated urban distribution network, buildings, factories and mines.


Compared with aluminum core cable, the copper core is flexible, the allowable bending radius is small, and it is not easy to break after repeated bending. Therefore, aluminum cable should not be used when there are many bends, many pipes or complex lines.
As the terminals of electrical switchgear are made of copper, copper and aluminum are directly connected, and the chemical reaction of primary battery will occur after power on: aluminum with higher activity will accelerate oxidation, resulting in higher resistance and lower current carrying capacity at the joint. Therefore, some measures need to be taken when copper and aluminum are connected, such as using copper aluminum transition terminal or copper aluminum transition terminal block, Eliminate electrochemical reaction.

Why are mineral insulated cables so hot?

In recent years, the city has developed rapidly
Subway, station, hospital, school, high-rise housing
Expansion of public facilities construction
The number of high-rise buildings has soared
The demand for urban electricity is rising
Such a densely populated focus area
Serious consequences of fire
In recent years, the fire spread trend of such sites presents similar pattern

Analysis of experts in building and safety fire protection
There are still many AAC Cables for public facilities
No fire protection
It is difficult to play an appropriate role in the fire
The law expressly stipulates that the fire protection system needs mineral insulated cable in the code of fire protection design of building engineering to pass the fire inspection and acceptance.
Because mineral insulated ABC Cable can not only ensure the fire power supply within the fire duration (more than 180 minutes), but also will not delay the fire, no smoke and secondary disasters, thus winning valuable time for fire rescue.
It can be said that mineral insulated cable is a special cable used in the fire protection of important national facilities, large public areas, high-rise buildings and other places. Its fire resistance, durability, safety, reliability and economy are irreplaceable by traditional power cables.
1、 Structure form of mineral insulated cable
Chengtiantai mineral insulation cable is a kind of cable which is wrapped with copper sheath and separated from the conductor and sheath with magnesium oxide powder as inorganic insulation material (optional for outer sheath), and forms a close whole with metal core and sheath.
Magnesium oxide is also a kind of non combustible material, and it will not produce toxic smoke or other harmful substances when encountering high temperature. Therefore, the cable with magnesium oxide as the insulator of copper core and copper sheath has better performance and many advantages.
2、 The properties and advantages of mineral insulated cables
Chengtiantai mineral insulation cable mainly includes bbtrz (flexible mineral insulated fire-proof cable) and yttw (flexible inorganic mineral insulation cable), which has good fire resistance, high temperature resistance, high carrying capacity, waterproof, corrosion resistance, mechanical damage, radiation resistance, electromagnetic compatibility, beautiful and generous appearance. At the same time, the cable will not emit any smoke under fire conditions Halogen and toxic and harmful gases.
1. Fire protection performance
Because mineral cables are all made of inorganic materials, they will not cause fire, combustion or combustion supporting, and toxic gas will not be produced. Even if there is fire outside, the cable can still work normally. Mineral insulated cable is made of magnesium oxide as insulator, and the melting point of magnesium oxide is as high as 2800 ℃, which is difficult to burn easily, so the fire resistance of mineral insulated cable is excellent.
The test shows that the mineral insulated cable can be operated normally for 2 hours in a flame with temperature of 800 ℃ -900 ℃; The cable is still intact and continues to operate normally after 30 minutes of combustion under the flame of 1000 ℃.
2. High temperature resistant operation, high load flow
The normal operating temperature of mineral insulated cable can reach 250 ℃, and in special cases, the cable can be maintained in a short time at the temperature close to the melting point of copper sheath. It is very suitable for laying in high temperature places, such as metallurgy, boiler, glass furnace, blast furnace and other environments.
The cut-off flow of MgO powder is far higher than that of other cables. Because magnesia powder has better conductivity coefficient than plastic, the same working temperature and flow rate are larger. For lines with more than 16mm, one section can be reduced, and two sections can be reduced for places where people are not allowed to contact.

3. Waterproof, explosion-proof, high mechanical strength
The insulation layer of mineral insulated cable is processed by high density compaction process, and then protected by seamless copper sheath. In the product standard, it must be subject to three requirements of fire resistance, spray resistance and mechanical impact resistance, which can withstand severe impact and mechanical damage. Therefore, it not only prevents the water, moisture, oil and some chemical substances from being infringed, but also suitable for connecting the explosion-proof equipment and equipment in places with explosion risk.
4. Overload protection
When the line is overloaded, the plastic cable will cause insulation heating or breakdown due to over-current or overvoltage. For mineral insulated cables, as long as the heating temperature of copper is not reached, the cable will not be damaged. Even if the breakdown occurs in a short time, the high temperature of magnesium oxide at the breakdown point will not form carbides. After overload removal, the cable performance will not change and can still be used normally.
5. Long service life, more safe and reliable
Because the structure of mineral insulated cable is composed of copper core and insulating sheath, it is a closed whole, so it is difficult for the material to aging due to the oxygen action in the outside air. This makes the overall service life of the cable longer (2-3 times the life of the ordinary cable), and the copper sheath’s own characteristics make the cable better grounded, Therefore, the lightning protection and grounding measures are effectively implemented, so as to ensure the safety and reliability of the electrical line operation.
Due to the many excellent characteristics of mineral insulated cables, many electrical design codes or standards have been adopted in recent years, and also used in many engineering projects in different industries. It can be expected that the use of mineral insulated cables in China will increase greatly in the next ten years.

Teach you to choose high quality wire through insulating layer!

The relationship between the rated voltage of cable and the number of cable cores

1、 Selection conditions of 1-5-core cable for 1kV and below
(1) Single core cable
When the line is long and the working current is large, or when it is laid under water, in order to avoid or reduce the intermediate joints, or when the single core AAC Cable has better comprehensive technical economy than the multi-core cable, the single core cable can be selected.
Low voltage DC power supply circuit, when necessary, single core cable can be used.


(2) Core cable
When the neutral point of 1kV and below power supply is directly grounded, the number of cable cores of single-phase circuit, when the protection line and neutral line share the same conductor, the 2-core cable shall be used.
2-core cable should be used for DC power supply circuit.
(3) Core cable
When the neutral point of 1kV and below power supply is directly grounded, the number of cable cores of single-phase circuit is: when the protection line and neutral line are independent, 3-core cable should be used.
(4) Core cable
For 4-core cable (3 + 1 cable) of 1kV and below, the fourth core not only serves as protective grounding, but also transmits unbalanced current and short-circuit current of power system. Its size is determined by unbalanced current and short circuit current, but generally not less than 1 / 2 of phase line.
When the protective line and neutral line share the same conductor, 4-core cable should be used in the three-phase four wire low-voltage distribution system of 1kV and below, instead of 3-core cable combined with single core cable to form a loop, or even directly using the metal sheath or armor layer of 3-core cable as neutral line. Otherwise, when the three-phase current is unbalanced, it is equivalent to the operation state of single core cable, which is easy to cause power frequency interference.
(5) Core cable
For the three-phase four wire low-voltage distribution system of 1kV and below, some distribution lines of electrical devices with high safety requirements, and some communication centers and automation equipment that not only ensure electrical safety, but also have anti-interference grounding, the TN-C low-voltage distribution system with 5 cores should be adopted, so that the protection line (PE line) and neutral line (PN line) are independent, The cross-sectional area of cable core is generally 3 large, 2 small or 4 large, 1 small or 5 large.


2. Selection of medium and high voltage cable cores
For 3 ~ 35kV three-phase power supply circuit cable core number selection. When the loop or cable with large working current is laid underwater, 3 single core cables can be selected for each loop; In addition to the above conditions, 3-core cable should be selected. The 3-core cable can be of common package type or 3 single core cable stranding structure type.
For 110kV three-phase power supply circuit, except for laying in Lake, sea water and other places and when the cable section is small, three single core cables can be selected for each circuit.
For three-phase power supply circuits above 110KV, three single core cables shall be selected for each circuit.
For high voltage AC single-phase power supply circuits such as electrified railway, two core cables or two single core cables shall be selected for each circuit.
Single core cable should be selected for HVDC transmission system; Coaxial 2-core cable can also be used for underwater laying in Lake and sea.

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Japan plans to build its largest submarine cable

According to foreign media reports, in order to improve the environment for transmitting a large amount of electricity generated by renewable energy to the capital circle and Kansai consumer areas, Japan’s Ministry of economy, industry and other countries are exploring ways to enhance the transmission network by laying the largest submarine cable in China. The route connecting Hokkaido and Kanto and the route from Kyushu to China and Shikoku are very likely. The government has proposed to achieve the goal of net zero emission of greenhouse gases by 2050, and strive to achieve it through the leap forward expansion of renewable energy.

The Ministry of economy and industry began to discuss the adjustment of the national power supply wide area operation promotion organization (wide area organization) in March this year summarized the discussion plan. The government has positioned offshore wind power generation as the core of renewable energy in the future. The coastal areas of Hokkaido and Kyushu have many suitable places for stable wind, and efforts will be made to deliver power to urban areas.

The capacity of the line from Hokkaido to Kanto is 8-12 million KW, which is about 10 times of the 900000 kW transmission line connecting Hokkaido and Honshu. This paper discusses the submarine ACSR Cable as the largest capacity of transmission line in China. For the route, several options are considered, such as connecting to the Kanto region through the Pacific Ocean or the sea of Japan, and connecting to the northeast region.

According to the analysis, the distance of the line will reach nearly 1000 km. There are only two submarine cables connecting dozens of kilometers in Japan, which will be the longest one. Compared with the common AC power transmission line, the submarine cable transmits power by the DC mode with less loss.

As for the route from Kyushu To Kansai, new submarine cables (with capacity of 1.4-2.8 million KW) connecting Kyushu to China and submarine cables (with capacity of 700000-2.8 million KW) connecting Kyushu to Shikoku will be considered. In addition, the transmission equipment connecting the East Japan border with the West Japan border will be strengthened.

So far, the power giant has focused on connecting the company’s nuclear power plants, large thermal power plants and consumer areas within its jurisdiction to build a transmission network. It was pointed out that, together with the small capacity of transmission equipment in interconnected areas, it constituted an obstacle to the realization of renewable energy projects far away from consumption areas. The submarine cables under discussion are connected to or across the jurisdiction. If completed, it will achieve the change of transmission network appearance.

Huge construction costs are needed to strengthen the transmission network. Wide area agencies intend to curb costs as much as possible, and it is said that submarine cables cost 100 million to 180 million yen per kilometer (about 6.01 million to 10.81 million yuan). If the connection between Hokkaido and Kanto requires at least hundreds of billions of yen in construction costs, it may lead to a rise in electricity charges.

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The load that the indoor common wire can bear

Wire load is a concern before we buy wires. At present, the wire specifications commonly used in our life include 1 square wire, 1.5 square wire, 2.5 square wire, 4 square wire, 6 square wire, etc., so how many watts can these wires load? Let’s look at the number of watts the 1, 1.5, 2.5, 4, 6 square wires can load.

1、 How many watts can a square wire load

An “empirical formula” commonly used by electricians: as long as it is copper core wire, the cross-section area of each square millimeter can pass through the rated current of 4-5a safely; In the single-phase circuit of 220V, the current is about 4.5a for every 1kW power; In 380V three-phase balance circuit, the current is about 2a for every 1kW power. The above values are very close to the results calculated by physical calculation formulas. Therefore, in order to remember the “cumbersome” calculation formulas, electricians can remember these in the work. Then according to this algorithm, we know that: if the copper core wire is used in 220V single-phase circuit, it can safely carry the current passing through 1kW load; If used in three-phase balanced load (such as motor) circuit, the current passing through 2.5kW load can be safely carried.

2、 1.5 how many watts can the square wire load

If the power supply line is copper core wire, the first is that the maximum allowable working current for open wire installation is 20a, namely 4400 watts; The second is the concealed steel pipe, with current of 16a and power of 3520 watts; Third, PVC pipe is concealed, current is 14a, then the power is 3000 watts.

3、 2.5 how many watts can the square wire load

The power supply of 2.5 square wires is about 5500 watts, and the aluminum core wires are 2.5 square millimeter, 13a-20a, 4400 watts of 220VAC voltage, which is no more than 15A for a long time, and the maximum standard of 10A is not more than 15A.

4、 How many watts can the 4 square wires load

The 1kW of single-phase power supply is about 4.5a and 8kw is about 36a. The current carrying capacity of 4 square wires (single plastic copper wire) is about 30A. Smaller ones, change 6 square wires (single running power supply). Your watch and gate must be changed. Don’t use such a high power, minimum 4kw, also can. How much kilowatt power is the power supply of 4 square wires depends on whether you use 220V in your home or 380V in the factory. If the 4 square wires of 220 can load 6 to 8 kilowatts.

5、 How many watts can 6 square wires load

The power line diameter of the 6 square wire can load is not directly related to the power delivered. Generally speaking, 6 square wires are more than enough for air conditioning wires. The maintenance power supply on the construction site is generally 10X6 + 1×4 cable. As for the current intensity, according to my experience in construction, this kind of cable is generally controlled by 63A air switch. 6 square aluminum wire can load 6 kW, 6 square copper wire can load 10 kW.