Cable Quality Defects and Their Elimination Methods

The crosslinking degree (thermal elongation) is not acceptable

If the crosslinking degree is not up to the standard, the thermal and mechanical properties of the cable are not qualified and can not meet the requirements of the working temperature of 90℃. The reasons for the unqualified crosslinking degree are as follows: first, the formula is unqualified, and the type and proportion of the complex agent is improper, so the formula should be adjusted to solve the problem; Two is the vulcanization process is not appropriate, such as the pressure is too low, the line speed is fast, the cooling water level is high, The solution is to first find out what the reason is, it may be one or several reasons exist at the same time, and eliminate the reasons.

Disqualified structure and appearance

(1) The thinnest point of insulation layer thickness is lower than the minimum value specified in the standard, or the average thickness is lower than the nominal value. The reasons for the unqualified insulation thickness are high linear speed, small amount of extruder, improper selection of mold, etc.

The solution is to reduce the linear speed or extruder speed, adjust the size of the die.

(2) eccentricity

The reason for the eccentricity is that the mold is not adjusted or the suspension control has changed after being collected and adjusted.

The solution is to keep the drape as stable as possible during driving.

The cable outside the bamboo joint is caused by the electrical, mechanical system causes the traction speed is not stable, the second is the die core is too small, or the conductor outside diameter is not uniform.

The elimination method is to check the mechanical, electrical system, troubleshooting. Properly adjust the size of the core, control the outer diameter of suburban counties as uniform as possible, more than the process requirements of the strand can be used.

Surface scratch

(1) the ACSR conductor encounters the upper or lower wall or foreign body in the vulcanized pipe. Therefore, it is required to adjust the suspension degree, try to make the wire core move in the middle of the crosslinked pipe, and clean it up in time when foreign bodies are found.

(2) there is burnt material on the outer edge of die sleeve. The solution is to adjust the temperature of the mold sleeve when starting the car to prevent overheating. Once burnt, it should be stopped immediately, or it will not get better by itself.


Most of the impurities in insulating material and semi-insulating material are brought into the process of mixing and extruder feeding. During the operation, strict attention should be paid to the cleaning of the material to prevent external impurities from mixing. Another impurity is coke pimp, its existence affects the performance and service life of the cable, so the temperature is strictly controlled when mixing and extrusion, to prevent the occurrence of coke phenomenon.

Air bubbles

There are two possible causes of air bubbles in insulation. One is caused by extrusion. The solution is to choose the right mold. The shielding layer has bubbles, the main reason is that there is water in the material, before extrusion should be dry, two is not sufficient cooling, then there will be as follows, in the isometric circumference of the line core appears a circle of bubbles.

The elimination method is to strengthen cooling, rise the water level and lower the temperature of cooling water.

(1) Cable performance is not up to standard

Disqualification of free discharge and dielectric loss

Free discharge and dielectric loss unqualified causes are very complex, it has to do with external shielding. Whether the insulation contains bubbles and impurities, and the properties of raw materials are closely related. Elimination method is to keep raw materials clean, strictly according to the process of production.

(2) cable insulation breakdown

Cable insulation breakdown is mainly caused by the insulation material mixed with impurities and external damage. Due to the strict avoidance of external damage, impurities should be avoided as far as possible. Semi-finished products should be strictly managed to prevent tripping and bruising.

(3) cushion breakdown

The main reason for the breakdown of the cushion is that the steel has burr, roll edge and puncture the cushion. The method to eliminate the steel strip is not equal to the unqualified quality requirements. The cushion is made of plastic belt with greater hardness, and the thickness of the cushion should be ensured.

International Advanced Level of Environmental Protection Wire and Cable Indicators

Environmental protection wire refers to the material is environmental protection wire.

The material includes insulating material, conductor material and shielding material. Insulation such as PVC, irradiated cross-linked PVC (XL-PVC), irradiated cross-linked polyethylene (XL-PE), low smoke free (Halogen-free), silicone rubber, Teflon Telflon and so on. The environmental protection of insulation materials is mainly the EU’s RoHS environmental protection directive and the EU’s environmental regulations on children’s toys do not contain 6P (Non-6P), that is, does not contain phthalates. Now the most environmentally friendly is low smoke halogen-free, does not contain halogen elements.

The most common conductor material is copper. Copper has bare copper (brass, red copper), tinned copper, silver-plated copper wire, etc., which are essentially copper, but the surface is plated with other substances. Now there are copper – coated aluminum and copper – coated steel conductors on the market. If the electrical performance requirements are high, copper is the best. The environmental protection of conductors is mainly required to be free of heavy metals (RoHS).

Environmental protection cable means that it does not contain lead, cadmium, hexavalent chromium, mercury and other heavy metals, and does not contain brominated flame retardants. The environmental protection performance of the cable is tested by SGS recognized testing institutions, and it is in line with the European Union Environmental Protection Directive (ROSH) and higher than its index requirements. No harmful halogen gas, no corrosive gas, less fever when burning, no pollution of soil wires and cables.

Main technical indicators:

  1. Rated voltage: 450/750V and below
  2. The maximum permissible operating temperature of the conductor shall not exceed 70 ℃, 90 ℃ and 125℃ respectively.
  3. Cable combustion smoke density in line with GB/T 17651-1998 (equivalent to IEC1043) standard requirements, light transmittance ≥60%.
  4. Cable halogen acid content test conforms to GB/T 17650-1998 (equivalent to IEC 754-2) standard requirements.

(1) PH ≥4.3

(2) Conductivity ≤10μs/mm

  1. The flame retardant performance of the cable conforms to the requirements of GB/T 12666-1990.

6.Toxicity index of cable ≤3.

There are Six Materials for the Cable

We are commonly used are super five types of lines or six types of lines, although they are all cable, but the cable material is also divided into several kinds, most of them are in line with the national conditions of production!When buying a line, don’t be a pit!Don’t be greedy for cheap!

First, four iron four aluminum wire

Four iron four aluminum is one of the worst quality cable, transmission quality is poor, it is easy to appear attenuation.Resistance is about 50 Ω 100 m, up to transmit 60 meters.

The differences are as follows:

  1. Aluminum mesh wire, the inner layer of the wire skin without luster, A pull will be broken.
  2. The easiest way to do this is to use a magnet to attract the wire. If it is attracted to the wire, it proves that there is iron in it.
  3. The four wire cores of iron and aluminum are made of different materials. Compared with all copper, materials such as copper-clad aluminum are much harder.
  4. With fire, the hardness of iron is very high, with fire, will not be soft soon.

Two, copper clad copper wire

Copper coated copper wire refers to the bronze outside and coated with a layer of oxygen free copper, so it is also called bronze wire.This kind of wire is generally ignored by everyone, not many people understand it, the conductor of the bronze wire belongs to the secondary furnace copper, which contains more impurities.Resistance is about 100 meters, around 40 Ω can transfer about 80 meters, the oxidation resistance is strong, long service life.

The resistance of bronze is much higher than that of ordinary copper-aluminum and oxygen-free copper, so the effective propagation distance of copper-bronze is much less than that of copper-aluminum.However, the physical properties of copper is still relatively stable, not easy to oxidize, so the service life is longer, because the surface is plated with a layer of oxygen-free copper, the surface does not see any difference, but with fire, the oxygen-free copper layer on the surface of the copper will soon melt away.Generally speaking, 0.4 all-copper wire can only reach 80 meters, 0.45 all-copper wire can reach 90 meters, and 0.5 all-copper wire can reach 100 meters.

Three, copper coated aluminum wire

The material of copper cladding wire is an oxygen-free copper layer on the surface of the copper core of aluminum or aluminum/steel alloy core.Because aluminum conducts electricity less well than copper, the DC resistance of copper-clad aluminum conductors is greater than that of pure copper conductors.If used as a power supply, copper-clad aluminum conductors will incur additional power consumption and a much lower voltage.100 meters would be about 28 Ω resistance, to sell cheap and transmission can be roughly 100 meters, poor oxygen resistance, long service life.The tensile strength of copper-clad aluminum is lower than that of copper conductor.Do not pull the cable body vigorously during use.Why is copper-clad aluminum mesh wire more easily oxidized?Because copper and aluminum are two metals with different electrodes, in a humid environment, copper and aluminum also have a small amount of water vapor containing impurities to form a galvanic cell.Aluminum is the negative electrode, copper is the positive electrode, the metal aluminum is corroded, so it can not be placed in the place of high air humidity.So in the choice of cable, how to see their use is copper aluminum cable?Fire can be used, if the core of the wire is quickly softened (this identification method is very practical), it proves that the copper core of the wire contains aluminum.

Four, high conductivity aluminum mesh wire

High conductivity aluminum wire, its composition is not just copper silver composition, in fact, is a kind of copper aluminum silver alloy of high performance wire, usually also known as copper coated silver.Has a resistance is small, the characteristics of the transmission is far, compared with the copper, iron and aluminum cable, resistance would be about 20 Ω 100 meters, can transmit 120 meters, but the oxygen resistance is poor, life is not long.There are three main kinds of high conductivity aluminum mesh wire: copper coated aluminum mesh wire (aluminum in the middle, the surface is thin oxygen-free copper layer), high conductivity aluminum mesh wire (imported aluminum, copper coated surface), copper coated silver mesh wire (imported aluminum, full copper coated layer)


Five, copper coated silver cable

The main material of copper coated silver wire is imported aluminum, which is higher in purity than copper coated aluminum wire and high conductive aluminum wire. The inner and outer leather is made of new materials.Resistance would be about 15 Ω 100 meters, which can transmit 150-180 meters, but the oxygen resistance is poor, life is not long.Copper coated silver because it can be transmitted far, we can generally be used in ADSL, computer room, supermarket, warehouse such occasions, the general network transmission is no problem.Compared with the copper coated silver wire, the transmission speed is not so long, but it is not far away. It can also be used in supermarkets, warehouses, and families in small and medium-sized areas.There is also a small amount of aluminum in the copper – silver – coated wire, and aluminum is easily oxidized.With four or five years will probably be oxidized, so in the use of choice, to consider this factor.

We can see from the copper core wire skin, generally speaking, all copper wire is the outer new material, and oxygen free copper is inside and outside the new material.You can see from the luster of the leather and cut a section of the leather to see if it can be drawn. The bright luster is the new material, and the new material can be drawn.But now all copper wire also tends to inside and outside the new material, so it can only be used as a basic basis.

You can also use a knife to scratch a surface or cross section:

Oxygen-free copper wire: scrape off the surface of a layer, the color is basically no difference, the cross section color is uniform, no difference.Bronze wire: scratch off a layer of surface, surface and interior color difference, cross section has a little white spots.You can also use fire, copper surface coated with a layer of oxygen-free copper, in the burning process, you will find oxygen-free copper outer layer will melt, and then wipe with paper, will find that the copper core is difficult to change back to the original brass color;And oxygen-free copper does not contain impurities, in the burning process, only the surface oxidation, after wiping with paper, or restore yellow.

According to the standard, the oxygen content in the oxygen-free copper wire is not more than 0.003%, the total impurity content is not more than 0.05%, and the purity of copper is more than 99.95%.Therefore, oxygen-free copper has high conductivity, good processing performance, welding performance, corrosion resistance and low temperature performance, and is suitable for high quality wire material.Oxygen-free copper cable 10 Ω resistance is about 100 meters of less than, can transfer about 120-150 meters, the signal transmission distance, packet loss rate is low, so in high-definition monitor network engineering, network engineering and home decorating go dark lines are suggested to use oxygen free copper, network stability is guaranteed, the oxidation resistance is strong, long service life.

So here’s the problem:

The above mentioned 6 materials of network cable, two of which have a relatively high transmission distance, theory can transmit about 150 meters, copper coated silver and oxygen free copper, then which one is better?Under normal use environment, the service life of the copper coated silver wire is much shorter than that of the oxygen free copper wire. The antioxidant of the copper coated silver wire is very poor, and the longest can be used for 4-5 years. The oxygen free copper wire can be used for more than 10 years due to its high purity and high antioxidant.When using copper coated silver cable, it should be noted that whether to use copper coated silver or not depends on the service life.

A final note:

Referring to various material cable transmission distance, before mentioned their resistance, cable transmission distance has much to do with the resistance, the smaller the resistance, the smaller the loss, transport the farther the distance, can be seen from the above, oxygen-free copper cable resistance minimum, and resistance to oxidation, it is also the reason why we should choose in the actual project it.

Cable Knowledge: Classification, Use and Function of Armoured Cables

ABC cable is made of conductors of different materials mounted in insulated metal bushing, which is processed into a flexible and solid assembly.Armoured cable is generally fixed power cable, generally speaking, is fixed in a place and basically do not move, power line transmission of electric energy.The armoured cable includes armoured thermocouple, armoured thermal resistor, armoured heater and armoured lead, which are mainly used for temperature measurement, signal transmission and special heating in chemical industry, metallurgy, machinery manufacturing, power generation and scientific experiments. The largest amount of armoured thermocouple is used.

Classification of Armoured Cables

Armoring is classified into steel tape armoring (22,23), fine steel wire armoring (32,33) and coarse steel wire armoring (42,43).

Steel tape armoured cable models are VV22, VVP22, ZRVV22, NH-VV2;

Control cable steel tape armoured cable, models are KVV22, KVVP2, KVVP22, ZR-KVV22

Steel wire armoured power cable, model VV32, YJV32, ZR-VV32

Steel wire armoured control cable Cable model KVV32 KVVP32

Armored communication cable models: HYA53, HYAT53, HYA23, HYV22, HYA22(rat proof, buried)


 Model Meaning of Armoured Cable

In order to enable the cable to withstand the radial pressure, double steel tape and gap wrapping technology is adopted, which is called steel tape armoured cable.After the cable is finished, the steel strip is wrapped around the cable core and the plastic sheath is extruded. This type of cable is expressed as control cable KVV22, plastic cable VV22, communication cable SYV22, etc.The two Arabic numerals in the subscript of the cable type, the first one: “2” means double steel tape armoured;The second: “2” represents the PVC sheath, such as the use of polyethylene sheath to change the “2” to “3”. This type of cable is generally used in the bearing pressure is relatively large occasions.For example: through the highway, square and vibration of the highway, railway side, etc., suitable for buried, tunnel and pipeline laying. In order to make the cable able to bear large axial tension, the cable is wrapped with several low carbon steel wires, which is called steel wire armored cable.After the cable is finished, the steel wire is wrapped on the core wire according to the necessary pitch and then the sheath is extruded. The representation method of this cable type is such as control cable KVV32, plastic cable VV32, coaxial cable HOL33, etc. Two Arabic numerals in the model, the first one: “3” represents fine steel wire armor;Second: “2” for PVC sheath, “3” for polyethylene sheath.This type of cable is generally used in large span, laying the occasion of large drop.

Application of Armored Cable

Armour cable mechanical protection layer can be added to any structure of the cable, to increase the mechanical strength of the cable, improve the ability of corrosion resistance, is designed for the vulnerable to mechanical damage and erosion of the area.It can be laid in any way, and it is more suitable for direct buried laying in rock areas. Armoured cable is generally fixed power cable, generally speaking, is fixed in a place and basically do not move, power line transmission of electric energy. In addition to the above purposes, the cable with armoured layer can also enhance the tensile strength, compressive strength and other mechanical protection to extend the service life. Armour has a certain resistance to external force, but also can be wary of rat bite, not through the armor caused by power transmission problems, the bending radius of the armor should be large, the armor layer can be grounded, protect the cable. Foreign armoured cable production is mainly concentrated in several more developed countries, such as the United States, Britain, Japan, Germany, Russia, Southeast Asia has no manufacturers, but as long as there are chemical, metallurgy, machinery manufacturing, power generation and other industries where there is temperature measurement, the need for armoured cable.

The Role of Armoured Cable

Armoured cable refers to the cable with metal armored protective layer. The purpose of the cable with armored layer is not only to enhance the tensile strength, compressive strength and other mechanical protection to extend the service life, but also to improve the anti-interference performance of the cable through shielding protection. The commonly used armoring materials include steel strip, steel wire, aluminum strip and aluminum tube, among which the steel strip and steel wire armoring layer has high magnetic permeability and good magnetic shielding effect, and can be used to resist low frequency interference, and can make the armored cable buried directly without penetrating the pipe, and is cheap and fine, so it is widely used in practice.

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.


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.

Corrosion resistance of aluminum alloy conductors

Aluminum alloy power conductor is a new type of material power cable that uses AA8030 series aluminum alloy material as the conductor and adopts special roll forming wire stranding production technology and annealing treatment. Alloy power cables make up for the shortcomings of pure aluminum cables in the past. Although the electrical conductivity of the cable is not improved, the bending performance, creep resistance and corrosion resistance are greatly improved, which can ensure that the cable remains continuous during long-term overload and overheating. The performance is stable. The use of AA-8030 series aluminum alloy conductors can greatly improve the conductivity and high temperature resistance of the aluminum alloy cable, while solving the problems of pure aluminum conductors and creep. The electrical conductivity of aluminum alloy is 61.8% of the most commonly used benchmark material copper IACS, and the current carrying capacity is 79% of copper, which is better than the pure aluminum standard. But under the same volume, the actual weight of aluminum alloy is about one-third of copper. Therefore, the weight of the aluminum alloy cable is about half of the copper cable at the same current carrying capacity. The use of aluminum alloy cables instead of copper cables can reduce the weight of the cable, reduce the installation cost, reduce the wear of the equipment and the cable, and make the installation work easier.

The inherent anti-corrosion performance of aluminum comes from the formation of a thin and strong oxide layer when the AAAC Conductor surface is in contact with air. This oxide layer is particularly resistant to various forms of corrosion. The rare earth elements added to the alloy can further improve the corrosion resistance of the aluminum alloy, especially the electrochemical corrosion. Aluminum’s ability to withstand harsh environments makes it widely used as conductors for cables in trays, as well as many industrial components and containers. Corrosion is usually related to the connection of different metals in a humid environment. Corresponding protective measures can be used to prevent corrosion, such as the use of lubricants, antioxidants and protective coatings. Alkaline soil and certain types of acidic soil environments are more corrosive to aluminum, so directly buried aluminum conductors should use insulating layers or molded sheaths to prevent corrosion. In sulfur-containing environments, such as railway tunnels and other similar places, the corrosion resistance of aluminum alloy is much better than that of copper.
Aluminum alloy has very good bending properties, and its unique alloy formula and processing technology greatly improve flexibility. Aluminum alloy is 30% more flexible than copper and has a 40% lower resilience than copper. Generally, the bending radius of copper cables is 10-20 times the outer diameter, while the bending radius of aluminum alloy cables is only 7 times the outer diameter, making it easier to connect terminals.
Armor characteristics
Commonly used armored cables are mostly armored with steel tape, with low security level. When subjected to external destructive forces, their resistance is poor, which is easy to cause breakdown, and the weight is heavy, the installation cost is quite high, and the corrosion resistance is poor. The life is not long. The metal interlocking armored cable we developed according to American standards uses aluminum alloy tape interlocking armor. The interlocking structure between layers ensures that the cable can withstand the powerful destructive force from the outside, even if the cable is subjected to greater pressure The cable is not easy to be punctured under the impact force, which improves the safety performance. At the same time, the armored structure isolates the cable from the outside world. Even in the event of a fire, the armored layer improves the flame-retardant and fire-resistant level of the cable and reduces the risk of fire. Compared with the steel tape armored structure, the aluminum alloy tape armored structure is lighter in weight, convenient to lay, and can be installed without bridges, which can reduce installation costs by 20% to 40%. According to the different places of use, different outer sheath layers can be selected, which makes the use of armored cables more extensive.

What are the differences between YJV3+2 and YJV4+1 cables?

The YJV power cable  is composed of one or several soft wires, and the outer covering is covered with a light soft sheath; the cable is composed of one or several insulated wires, and the outside is covered with a tough outer layer made of metal or rubber.

As we all know, there are single-core cable and multi-core distinctions in wire and cable. Single-core cable means that there is only one conductor in an insulating layer, and multi-core means that there are multiple conductors in an insulating layer. Then there will be doubts from users who don’t know. 3+2 cores and 4+1 cores are both 5 cores. What is the difference between them? YJV3+2 and YJV4+1 cables are wires and cables.  In fact, these two kinds of wires and cables have their own characteristics.

The 3+2 and 4+1 on the YJV power cable indicate the number of cores of a cable. There are 2 or 3, 3+2, 4+1, and 5 wires that are insulated from each other in a cable, respectively Called 2-core or 3-core, 3+2 core, 4+1 core, 5 core wire.

What is the difference between YJV3+2 cable and YJV4+1 cable in the model name?

1.YJV 3+2 core

3 of the 3+2 cable is the three phase wires (L1, L2, L3 phase wires, the diameter of these three wires is large), the diameter of the wires is the same, 2 is the neutral wire and the PE wire, and one wire is used to connect the neutral wire (N in The diameter of this wire is smaller than L1, L2, L3), and one wire is used to connect to the grounding wire (PE grounding protection wire, this diameter is also smaller than L1, L2, L3).

2.YJV 4+1 core

The 4 of the 4+1 cable means that the diameter of the three phase wires is the same as the diameter of the neutral wire, 1 means that the PE ground wire has a single diameter; 4+1 means that a cable consists of 4 wires, one of which is used to connect to the live wire (L1 phase wire). ), one wire is used to connect to the neutral wire (N neutral wire), and one wire is used to connect to the ground wire (PE grounding protection wire).

The above is about the structure difference between YJV3+2 cable and YJV4+1 cable, and the difference in naming. We all know that cables are named based on models, and different models of cables are different in nature, and each model of cable has its own characteristics.

General Rubber Plastic Wire Structural Characteristics

Requirements of General rubber plastic wire:
1. Scope of application: connection and internal installation of power, lighting, electrical equipment, instrumentation and telecommunication equipment with AC rated voltage of 450/750V low voltage cable and below.
2. Laying occasions and methods: indoor open laying and communication channels, along the wall or overhead laying in tunnels; outdoor overhead laying, laying through iron pipes or plastic pipes, electrical equipment, meters and radio installations, all fixed laying; plastic The sheathed wire can be directly buried in the soil.
3. General requirements: economical and durable, simple structure.
4. Special requirements:
1) When laying outdoors, due to the influence of sunlight, rain and freezing conditions, it is required to be resistant to the atmosphere, especially sunlight aging; cold resistance requirements are required in severe cold areas;

2) In use, it is easy to be damaged by external force or flammable, and it should be worn in the occasions where it is in contact with oil. When the pipe is worn, the wire is subject to greater tension and may be scratched, so lubrication measures should be taken;
3) When used internally for electrical equipment, when the installation location is small, it should have a certain degree of flexibility, and require clear color separation of the insulated wire core, and should be matched with the corresponding connector terminals and plugs to make the connection convenient and reliable; for occasions with electromagnetic protection requirements , Shielded wires should be used;

4) For high ambient temperature occasions, sheathed cables should be used; for special high temperature occasions, heat-resistant cables should be used.

Structural features
1. Conductive core: when used for internal installation of power, lighting and electrical equipment, copper core is preferred. For large cross-section wires, it is better to use compact core; bare conductors for fixed installation generally adopt category 1 or category 2 conductor structure .
2. Insulation: Insulation materials generally use natural styrene-butadiene rubber, polyvinyl chloride (PVC) cable, polyethylene, and nitrile polyvinyl chloride compound; heat-resistant wires use polyvinyl chloride with a temperature resistance of 90°C.
3. Sheath: There are generally five types of sheath materials: polyvinyl chloride, cold-resistant polyvinyl chloride, anti-termite polyvinyl chloride, black polyethylene, and neoprene rubber.

Especially cold-resistant and outdoor overhead laying should use black polyethylene and neoprene sheathed wires.
In environments with external forces, corrosion, humidity, etc., rubber or plastic sheathed wires can be used.