Talk about the common misunderstandings of those wires and cables

Nowadays, there are many kinds of wires and cables, and their performances are diverse. When buying All Aluminum Alloy Cable

, many people choose to learn about the various parameters and evaluations of the cables on the network, but because the information on the network is too complicated, it is difficult to distinguish between true and false. , Some wrong viewpoints will cause misunderstandings to many people who browse and watch, so many misunderstandings about wires and cables are formed. Here is a summary of several common misunderstandings.

Misunderstanding 1: There is radiation in wires and cables

Many people have seen on the Internet that wires and cables have radiation. To be honest, there is radiation, but those who have a little knowledge of physics should know that everything that uses electricity has radiation. Even an electric fan has radiation. Except for those high-risk radiation products, the amount of radiation from ordinary wires and cables is negligible and basically negligible.

And what you may not know is that the radiation of wires and AAAC cables is even weaker than that of the mobile phones we carry around every day, so those who are afraid of radiation from wires and cables, the first thing to do is not to stay away from wires and cables, but Throw away the phone quickly.

There are also some people who worry about the magnetic field generated by wires and cables, and think that this kind of magnetic field has an unhealthy effect on the human body. If they are worried about the magnetic field, it is even more nonsense, because everyone knows that our earth has a natural geomagnetic field , And it has a larger range and stronger power. If the magnetic field is not good for the human body, the entire earth is no longer suitable for human habitation. Our Mars immigration plan can only be started in advance, so we are worried about the radiation magnetic field of wires and cables.

How to find the fault point after the ACSR cable is short-circuited?

Generally speaking, when the ACSR conductor has a short-circuit fault, the air switch cannot be closed, which will not only cause a small-scale power failure, but if it is not handled properly, it may sometimes expand the scope of the fault and even cause an electric shock accident. Therefore, if the short-circuit fault is not eliminated, illegal power transmission is absolutely not allowed.

When dealing with a short-circuit fault of a cable, try not to break the cable destructively. In that case, it will damage the cable insulation, reduce the insulation strength of the cable, and cause electric shock. So, how to find the short-circuit point quickly and effectively when the cable has a short-circuit fault?

 

 

The main methods are as follows:

1. The place where the cable has a connector is the frequent occurrence point of cable short-circuit faults. When searching, the main search object is the cable connector.

ASTM 477 MCM ACSR Cable

2. If ASTM 477 MCM ACSR Cable is erected for a long distance, and there is a short circuit in the middle or at the end of the cable, the tripping time of the air switch may be delayed. This is because the short-circuit point is far from the air switch and there are A certain resistance value reduces the short-circuit current. If this is the case, the section of cable from the short-circuit point to the circuit breaker will definitely heat up and be higher than the temperature of the human body, and the rubber sheath will become soft or even bulge. At this time, touch the hot cable with your hand until it suddenly becomes cold. The place where you feel the cable hot is the short-circuit point.

3. If it is a two-core lighting cable, the light bulb from the short-circuit point to the power circuit breaker will emit light, but due to insufficient voltage, the light will be dim, and the light bulb after the short-circuit point will not light up at all.

Requirements for power cable use

Power cables are usually rope-like cables formed by twisting several or several groups of wires. Each group of wires is insulated from each other and is often twisted around a center. The entire outer layer has a highly insulating coating. They are mostly erected in the air, underground, or underwater for telecommunications or power transmission. Cables can be divided into power cables, communication cables and control cables according to their uses. So are there any safety requirements when using the cable? Let’s look at it in detail next.

1. When the cables cross each other, the high-voltage cables should be under the low-voltage cables. If one of the cables is protected by a pipe or separated by a partition within 1m before and after the intersection, the smaller allowable distance is 0.25m.

2. When the cable is close to or crossing the heating pipe, if heat insulation measures are provided, the smaller distance between parallel and crossing is 0.5m and 0.25m respectively.

 

 

3. When the ACSR conductor crosses the railway or road, it should be protected by a pipe. The protective pipe should extend 2m beyond the track or road.

4. The distance between the cable and the foundation of the building should be able to ensure that the cable is buried outside the building’s scattered water; when the cable is introduced into the building, it should be protected by a pipe, and the protective pipe should also exceed the building’s scattered water.

 

5. The distance between the cables directly buried in the ground and the grounding of the general grounding device should be 0.25~0.5m; the buried depth of the cables directly buried in the ground should generally not be less than 0.7m, and should be buried under the frozen soil layer.

The above is about the safe use of wires and cables. When using wires and cables, they must be in accordance with the standards to prevent the wires and cables from causing losses.

Factors that cause power cables to overheat

AAAC Condutors are the basic facilities for transmitting electrical energy to every household or unit. Without it, we can enjoy modern life without electricity. However, precisely because it is placed in our work and living environment, it also brings certain hidden dangers to our lives, lives and work. There are countless fires caused by overheating of AAAC cables, whether at home or abroad, so what causes the overheating of wires and cables to cause fires? The following wire and cable manufacturers will give you a good introduction to what are the factors that cause the wire and cable to overheat? So everyone can be on guard.
1. The cable conductor resistance does not meet the requirements, which will cause the cable to overheat during operation. There is also improper cable selection, the conductor cross-section of the cable used is too small, and overload occurs during operation. After long-term use, the heating and heat dissipation of the cable will be unbalanced and cause overheating.


2. The partial sheath of the armored cable is damaged, which will cause slow damage to the insulation performance after water enters, resulting in a gradual decrease in insulation resistance, and overheating during cable operation.
3. When the cables are installed too densely, the ventilation and heat dissipation effect is not good, or the cables are too close to other heat sources, which affects the normal heat dissipation of the cables, and may also cause the cables to overheat during operation.
Fourth, the joint manufacturing technology is not good, the crimping is not tight, resulting in excessive contact resistance at the joint, and also causing the cable to overheat. The insulation performance between phases of the cable is not good, resulting in low insulation resistance and overheating during operation.


See what acsr conductor manufacturers mentioned above, as long as we usually choose a regular manufacturer when buying cables, buy high-quality wires and cables, and equip them with appropriate cables according to the actual situation of the project or project. The wiring installation is scientific and reasonable. Then it will not easily cause the cable to overheat or even cause a fire.
The above are the factors that cause the overheating of the wires and cables, do you understand it? Hope it helps you.

What are the functions of ACSR cables?

There are too many types and specifications of cables, and if you explain them carefully, it will be very cumbersome. Therefore, today we mainly understand one of them: “flexible fireproof cable”. If you are not a professional, this may sound strange. But it is obvious from the name that this is a flexible cable. This kind of cable has the function of fire prevention; also known as mineral insulated cable, it has the advantages of good flexibility, excellent shielding performance, corrosion resistance, strong practicability, and long service life. It is widely used in demanding occasions.
Flexible fireproof cable function
1. Good flexibility: the cable can be coiled on the cable tray with a bending radius ≤ 20D (D is the outer diameter of ACSR  cable).
2. Large cross-section: the cross-section of single-core cable can reach 1000mm, and the cross-section of multi-core cable can reach 240mm.
3. Long continuous length: Whether it is a single-core cable or a multi-core cable, its length can meet the requirements of the power supply length, and each continuous length can reach 1000m.
4. Corrosion resistance: Organic insulated fire-resistant cables sometimes need to wear plastic pipes or iron pipes, plastic pipes are easy to become brittle, iron pipes are easy to rust, fire-resistant cables with copper sleeves do not need to wear pipes, and copper sleeves have good corrosion resistance此图像的alt属性为空;文件名为abc-cable-full-form.jpg
5. Good shielding performance: Put the fireproof cable on the same shaft as the information cable and control cable. Under the shield of the copper sheath, it will not interfere with the information transmitted by the signal cable and control cable.
6. Excellent fire resistance: its fire resistance not only meets the requirements of the national standard GB12666.6 A 950℃ and 90min, but also meets the test requirements of A grade 650℃ 3h, B grade 750℃ 3h and C grade 950℃ British bs6387-1994 3 hours specified in At the same time, it can withstand the water spray and mechanical shock during the combustion process.
7. Safe and reliable: fireproof cables can usually supply power in flames, reducing fire losses, especially for personal safety, which is particularly reliable. Its copper sheath is an excellent conductor and is the best grounding PE wire. Continuous use within the range improves the sensitivity and reliability of grounding protection.
8. Long service life: Inorganic insulating materials are resistant to high temperatures and not easy to age. Its service life is many times that of organic insulated cables.
Each side of the flexible fireproof cable has a relatively large advantage, and it will also have a higher utilization rate for different environments. If you need to use cables and wires in your life, you can look at one of the advantages of flexible fire-resistant cables and see if they can be used and needed. Of course, we must also grasp the comprehensive consideration of psychological choices when buying, the most appropriate is the best.

Do aluminum alloy cables have to have aluminum alloy copper connectors?

Nowadays, aluminum terminals or so-called alloy terminals that do not match the cable performance are used to connect aluminum alloy cables in China. Most electrical accidents occur at the connecting part of the connecting terminal and the cable conductor. The stability and reliability of the connection between the cable conductor and the connection terminal are very important for the power supply system. Therefore, in order to ensure that the advantages and value of aluminum alloy cables can be used and reflected, and safe, there is no hidden danger of using aluminum alloy cables, and aluminum alloy cable connectors that match the performance of the aluminum alloy cables must be used.


Aluminum terminals or the so-called alloy terminals that do not match the performance of the aluminum alloy cable should be connected, so the aluminum connection terminals or the so-called physical and mechanical properties that do not match the cable performance and the potential safety problems still exist, but the electrical of the terminal The performance and the performance of the AAAC Conductors are highly compromised, and problems such as the use effect still exist. This kind of connection solution is undoubtedly the wrong connection solution. It will bring fatal safety hazards to the user’s transmission line and also bring hidden dangers to the development of the industry.
As we all know, the connection application technology of aluminum alloy cable should be similar to that of copper cable and aluminum alloy cable. In other words, the copper cable is connected with the copper nose, the aluminum alloy cable is connected with the copper and aluminum transition terminal, and the aluminum alloy cable is connected with the aluminum alloy copper connection terminal. Its performance is the same as that of the aluminum alloy cable. It is the correct cable and connection solution.

Graphene: Let AAAC cables also “voice control”

The new material we are going to talk about this time may bring new changes to the material field of aluminum alloy cables. It is magic angle graphene. Some people say, isn’t it just graphene? I already knew it.
In fact, it is really not. The magic angle graphene we are going to talk about is not the graphene you understand. Different from graphene, magic angle graphene has a feature, that is, insulation and superconductivity will appear on the same material. We don’t know what this material can do in the field of cables, but it may open a sea of ​​unknowns to the cable industry.


Let’s get to know it now.
The “Magic Horn” is indeed like a magical angle. Graphene is originally a material with better conductivity than metal, but when two layers of graphene are stacked together, at a special angle, they suddenly become insulators.
According to our general understanding, insulators and superconductors are two extreme materials. The resistance of the insulator is very high, while the resistance of the superconductor is zero. However, when the two layers of graphene are at a special angle, they can easily bridge the gap between these two extremes. You can imagine that one day, the insulation of the cable you make is a conductor, and the conductor is also insulation, and you can change it at will. Anyone who makes materials knows that it takes time and effort to find new materials with certain characteristics. Because there is almost only one way to do this work, which is to keep sifting through a large number of materials. Whether you can find it is almost pure luck.
But the study of magic angle graphene has opened up new ideas for materials science. It makes scientists realize that materials science can accurately predict the performance of materials in advance and reduce a lot of work. Even materials science can construct new materials based on the underlying logic of material properties.


In early May 2020, Chinese young scientist Cao Yuan published two articles in the same issue of Nature, introducing some new discoveries of his team on “Magic Angle Graphene”.
To talk about this new hairstyle, we have to start with graphene. Graphene is a material with a thickness of only one carbon atom. More specifically, the carbon atoms will first form a hexagonal unit, and then spread out on the plane like a tile. If you compare it, it looks like a mosquito net. Common mosquito nets are covered with hexagonal holes, and each hole is like a unit of six carbon atoms in graphene.
If we randomly stack two layers of mosquito nets together, it is difficult to completely overlap the hexagonal holes, and there will always be a certain angle of misalignment. For graphene stacked in two layers, this angle will bring about a surprising change: at a special angle, graphene that has better conductivity than metal will suddenly become an insulator.
This special angle is the “magic angle”. When two or more layers of graphene are stacked at this angle, it is called “magic angle graphene.”
In fact, as early as 2011, some scientists discovered through theoretical predictions that when the angle between two layers of graphene is at a certain angle, the electrical properties of graphene will suddenly change. But at the time, there was only theory, no experiments.
In 2018, experiments appeared. The Pablo Jarillo-Herrero team of the Massachusetts Institute of Technology in the United States published a paper in the journal “Nature” and used experiments to prove that this prediction was valid. Chinese scientist Cao Yuan was the first author.
They twisted the stacked graphene at a very low temperature and found that when the angle between the two graphene layers is 1.08 degrees, there will be a sudden change in prediction, and the originally conductive graphene will suddenly become Insulator.
What is even more amazing is that as long as a small electric field is applied, the insulator will turn into a superconductor. This experimental result exceeds the original theoretical prediction.
In May 2020, Cao Yuan’s team made some new discoveries.
In one of his papers, it can be seen that on the original basis, they have studied three different angles of double-layer graphene, the three angles are 0.84 degrees, 1.09 degrees and 1.23 degrees.
After studying double-layer graphene stacked at these angles, Cao Yuan’s team came to an important conclusion. They revealed that magic-angle graphene is “tunable.” This is a proper term in a subject, but don’t worry, it’s not hard to understand.
For example, the voice-activated lights in the corridor will light up when there is a sound. But in the beginning, no one knew the connection between sound and light. Cao Yuan’s work in 2018 is like discovering a phenomenon, that is, shouting at the voice-activated light from a specific angle, and the voice-activated light can be switched between “on” and “off” freely.
Of course, there is no such phenomenon in real life, but it happens in the world of graphene, so it is very eye-catching.
In his work in 2020, Cao Yuan further discovered that the lighting is very sensitive to angle changes still near this angle. You still shout, but when you shook your head slightly to the left or right, the light can not only switch between “on” and “off,” it can also change into various colors. This is the so-called “tunability”.
Using this “tunability”, maybe one day our AAAC cables will become “voice-activated”.

Q&A about Cable and Wire

1. What are the requirements for fixing AC single-core cables? why?
The clamp should have no iron to form a closed magnetic circuit. This is because when the cable core passes current, magnetic lines of force are generated around it. The magnetic line of force is proportional to the current through the core. If iron and other magnetic materials are used, Electromagnetic induction knows that eddy current will be generated in the iron to make the cable heat up and even burn the cable. Therefore, iron pieces cannot be used as fixing fixtures for single-core AC cables.

2. What are the biggest features and advantages of the following heat shrinkable cable head accessories?
The biggest feature of heat shrinkable accessories is the use of stress tubes instead of traditional stress cones. It not only simplifies the construction process, but also reduces the size of the joint terminal, which is convenient to install, save time and labor, has superior performance and saves metal. The heat-shrinkable cable accessory integrates the perfusion type and the dry pack type into one, which combines the advantages of these two accessories.

3. What inspection work should be carried out before cable laying?
(1) The bracket should be complete and paint complete.
(2) The cable type, voltage, and specifications conform to the design.
(3) The cable insulation is good. When there is doubt about the sealing of the oil-paper cable, the damp judgment should be made; the direct-buried underground cable and the small bottom cable should pass the DC withstand voltage test; the oil sample of the oil-filled cable should pass the test.
(4) The oil pressure of the oil-filled cable should not be lower than 1.47MPa.

4. what does AAAC stand for?
AAAC means Aluminum Alloy Conductor ,is a concentric-lay-stranded conductor consisting of aluminum-alloy wires available in both single layer and multi-layer constructions.
All Aluminum-Alloy Conductors (AAAC) can be used in Medium, High and Extra-High voltage transmission lines. AAAC offers better sag performance due to the high strength-to-weight ratio provided by the aluminum-alloy. In addition, AAAC provides a higher corrosion resistance than ACSR conductors.

5.What is Quad Moose conductor?
Moose is one specification of ACSR conductor ,under British Standard EN50182 (BS215), which structured by 54 strands aluminum wire and 7 strands steel wire, single diameter of each wire is about 3.53mm.

6. What are the advantages of cross-linked heat shrinkable cable accessories?
Answer: This is a new type of material. Compared with other types of accessories, it has the advantages of superior electrical performance, small size, small quality, easy installation, and matching materials. In addition, it has weather resistance, pollution resistance, flame retardant self-extinguishing, etc. ability.

7. When there are doubts about the sealing of oil-paper insulated power cables, how to check whether the cable insulation paper is damp in a simpler way?
Answer: Ignite the cable insulation paper or put it in the cable oil at about 150℃ to check, there is no “hissing” or white foam, indicating that it is not damp.

8. What should be indicated on the cable sign? What are the requirements for writing?
Answer: The cable circuit design number, cable model, specification and starting point should be indicated on the sign, and the cables used in parallel should have a sequence number. The handwriting is required to be clear and not easy to fall off.

9. Where should the azimuth signs of directly buried cables be set?
Answer: At both ends of the cable, the cable connector is at 50~100m of the straight section of the cable and the corner where the cable changes direction.

10. How to make the yellow wax ribbon, black glass lacquer tape, alkali-free glass ribbon, etc. used to make cable joints before construction?
(1) Constant temperature drying method: roll the insulating tape into a small roll with a diameter of 25~30mm, put it in a 110~120℃ constant temperature drying oven for 4~5h, cool and dry it out, and put it into a dry sealed cylinder.
(2) Oil immersion and moisture removal method: Put the small coil of insulation tape into the cable oil at a constant temperature of 120~130℃, keep a distance of 30mm from the bottom of the pot, after a certain period of time, the oil surface will no longer produce foam, then take it out and put it into storage In the barrel with cable oil, the oil level should exceed all the contents and seal it.

What’s The Difference Between ACSR and AAAC cable ?

Following are some Q&A people interested about wire and cables :

1. What types of commonly used wires and cables are classified by purpose?
Answer: According to the purpose, it can be divided into bare conductors , insulated wires, heat-resistant wires, shielded wires, power cables, control cables, communication cables, radio frequency cables, etc.

2.What is the difference between ACSR cable and AAAC cable ?
AAAC:This bare concentric-lay-stranded conductor, made from round aluminum alloy 6201 -T81 wires, is constructed with a central core surrounded by one or more layers of helically laid wires.
it provide better corrosion resistance than the one produced by the aluminum conductor steel reinforced(ACSR).
ACSR: This bare concentric-lay-stranded conductor is made from round aluminum 1350-H19 (extra hard) wires and round zinc-coated or aluminum-coated steel core wire(s) to be used as overhead electrical conductors.it provides better strength than AAAC cable.

3. What kinds of insulated wires are there?
Answer: There are the following types of insulated wires: PVC insulated wires, PVC insulated cords, nitrile and polyvinyl chloride compound insulated cords, rubber insulated wires, direct buried aluminum core plastic insulated wires for agricultural use, and rubber insulated cotton yarn Textile cords, PVC insulated nylon sheathed wires, PVC insulated cords for power and lighting, etc.

4. What kind of occasion is the cable tray suitable for?
Answer: The cable tray is suitable for the overhead laying of power cables and control cables indoors and outdoors in general industrial and mining enterprises, and can also be used for indoor and outdoor installations in telecommunications, radio and television departments.

5. What are the cable accessories?
Answer: Commonly used electrical accessories include cable terminal junction box, cable intermediate junction box, connecting pipe and terminal block, steel plate junction box, cable tray, etc.

6. What is the cable middle connector?
Answer: The device that connects the cable and the cable’s conductor, insulation shielding layer and protective layer to connect the cable line is called the cable intermediate joint.

7. What is electrical main wiring?
Answer: The electrical main wiring is the connection method of the main electrical equipment and the bus in power plants and substations, including the connection of the main bus and the auxiliary power system according to certain functional requirements.

8.When choosing the cross section of the power cable, which regulations should be followed?
Answer: The selection of power cables should follow the following principles:
(1) The rated voltage of the cable should be greater than or equal to the rated voltage of the power supply system at the installation point;
(2) The continuous allowable current of the cable should be equal to or greater than the maximum continuous current of the power supply load;
(3) The cross-section of the core must meet the requirements of stability of the power supply system when it is short-circuited;
(4) Check whether the voltage drop meets the requirements according to the cable length;
(5) The minimum short-circuit current at the end of the line should enable the protection device to operate reliably.

9. What are the advantages of XLPE cables and oil-paper cables?
Answer: (1) Easy to install, because it allows a small minimum bending radius and light weight;
(2) Not restricted by line drop;
(3) Good thermal performance, high allowable working temperature and large transmission capacity;
(4) The cable accessories are simple and all are dry structure;
(5) Simple operation and maintenance, no oil leakage problem;
(6) The price is lower;
(7) High reliability and low failure rate;
(8) There are few manufacturing procedures, simple process and remarkable economic benefits.