Frequency Conversion Cable Structure Design

The energy saving effect of frequency conversion device is very obvious, the use of frequency conversion speed regulating motor in high power motor, the whole generator set can save 30% electricity. And after the use of frequency conversion speed regulation, the soft start of the motor is realized, so that the motor works smoothly, the motor bearing wear is reduced, and the service life and maintenance cycle of the motor are extended. Therefore, frequency control technology in petroleum, metallurgy, power generation, railway, mining and other industries have been widely used.

 

1. ACSR Cable design

For 1.8/3KW and below frequency conversion motor special cable, and symmetrical 3+1 core and 4 core cable can only be used for the main power supply input cable, but the best use of symmetrical structure cable. Inverter and frequency conversion motor ask cable all needs to adopt symmetrical cable structure, symmetrical cable structure with three core and 3 + 3 core 2 kinds, 3 + 3 core cable structure is a small four to three core insulation wire core in the fourth core (neutral) is decomposed into three smaller insulation wire core section, the three big three symmetrical string cable core cable, special cable for 6/10 kv frequency conversion motor, the cable structure and 6/10 kv power cable, ordinary ordinary power cable is three insulation wire core adopts copper tape screened cable, special cable is made by copper wire and frequency conversion motor copper tape screened after extruded phase splitting the sheath, and symmetric cabling, The symmetrical cable structure has better electromagnetic compatibility because of the interchangeability of the wires, which plays a certain role in suppressing electromagnetic interference, can offset the odd frequency in the high order harmonic, improve the anti-interference of the special cable for frequency conversion motor, and reduce the electromagnetic radiation in the whole system.

2.Design of shielding structure

The shielding of special cables for frequency conversion motor 1.8/3kV and below generally adopts the total shielding, and the shielding for special cables for frequency conversion motor 6/10kV is composed of phase separation shielding and the total shielding. The phase separation shielding can generally adopt copper tape shielding or copper wire and copper tape combination shielding. The total shielding structure can adopt copper wire and copper tape combined shielding, copper wire braided shielding, copper wire braided shielding, copper wire braided copper tape shielding, etc. The section of shielding layer and the section of main line core are in a certain proportion. The shielded cable with this structure can resist the interference of electromagnetic induction, bad grounding and power line conduction, reduce the inductance and prevent the induction electromotive force from being too large. The shielding layer can not only restrain the emission of electromagnetic wave, but also act as the channel of short-circuit current, which can protect the neutral wire core.6/10kV frequency conversion motor special cable, considering that the cable is often affected by radial external force in the process of use, galvanized steel belt pin mounting layer is added outside the cable shielding layer (isolation sleeve is added between the shielding layer and the steel belt pin mounting layer).The steel belt pin is mainly used as the radial mechanical protective layer of the cable, and it also plays an additional role of total shielding. In particular, the steel belt armor and the copper wire and copper belt shield are two different shielding materials, which play a complementary role in electromagnetic shielding, and the shielding effect will be better.

 

3.Overhead ACSR Cable 336.4 MCM design

1.8/3KV and below frequency conversion motor special cable electrical performance according to GB/ TL2706, 2002 standard design. In addition to meeting the GBT/ L2706.2002 standard, the cable for 6/10kV frequency conversion motor has increased the electrical performance requirements such as capacitance and inductance. According to the actual use of the special cable for frequency conversion motor and the technical conditions of GB/T 12706.2002 and ABB Company for electric power transmission cable, the electrical performance parameters of the cable are determined.

  1. Main manufacturing technology of cables

In the production process of special cable for frequency conversion motor, the extrusion process of insulating wire core and cable forming process are the most critical processes.

Insulation core extrusion process Insulation core quality will directly affect the electrical performance of the cable. In order to improve the quality of cables, we choose insulating materials with high electrical performance for production. For example, 10kV cross-linked insulating materials are used for 1.8/3kV variable frequency motor special cables, and 35kV cross-linked insulating materials are used for 6/10kV variable frequency motor special cables. Imported materials are used for conductor shielding, insulating shielding and insulating materials. In the production process, we pay special attention to the purification of raw materials, shielding and insulation material extrusion close, control insulation eccentricity and insulation diameter uniformity, which can reduce the interface effect, improve the electrical performance of the cable.

Variable frequency cable requires symmetrical structure, and uniform tension of insulating wire core must be ensured during cable construction, so that the length of wire core after cable construction should be kept as consistent as possible, otherwise it will lead to structural changes, resulting in inhomogeneity of capacitance and inductance, and affect the electrical performance of the cable.

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.

impurities

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.

Plastic Extrusion and Traction Speed of Cable Technology

The rate of plastic extrusion

According to the flow rate analysis of the viscous fluid in the material conveying and homogenizing section of the ABC conductor,  the flow rate of the plastic (that is, the extrusion speed) is proportional to the screw speed, and the screw speed is an important operating variable to characterize the extrusion speed in the extrusion process because of the convenience of adjustment. Therefore, in general, increasing the screw speed is an important means to improve the production capacity of modern plastic extruder and realize high-speed extrusion. But the analysis of the plastic melting length shows that the increase of the screw speed, on the one hand, increases the viscous dissipation heat due to the enhanced shear effect; On the other hand, in the absence of head pressure control, the screw speed increases, the flow rate increases, and the material stays in the machine time is shortened. Moreover, the influence of the latter is more than that of the former, and the normal extrusion process will be destroyed due to the extension of the melt length to the homogenizing section. Therefore, it is necessary to increase the screw speed to improve the extrusion speed, but also to increase the heating temperature or use the control of the head pressure to achieve the purpose.

Plastic extrusion speed or the quality of plasticizing is related to the use of plastic material and temperature control, the plasticizing temperature of various plastics is different. If you want to quickly extrude plastic, only the material is good, the temperature is appropriate, to achieve. In addition, the extrusion speed is closely related to the extrusion thickness. In the normal extrusion process, the amount of glue is large and the extrusion speed is slow. On the contrary, the extrusion speed is fast, on the premise of ensuring the quality, the extrusion speed can be appropriately improved.

Traction speed

Extruded products are dragged through the machine head by traction device, in order to ensure the quality of products, the traction speed is required to be uniform and stable, in coordination with the screw speed, to ensure the uniformity of extrusion thickness and outer diameter of products. If the traction speed is not stable, the extrusion layer is easy to form bamboo joints, and the extrusion thickness is large when the traction speed is too slow, and the phenomenon of glue stacking or empty pipe occurs. When the traction speed is too fast, it is easy to cause extruding and thinning, or even the phenomenon of degumming and leakage. Therefore, in the normal extrusion process, we must control the traction speed.

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.

The Advantages of Copper Cable and Aluminum Cable

We all know that copper and aluminum are the main materials of wire and cable, so who knows what advantages copper cable and aluminum cable have?

1.Low resistivity: the resistivity of copper-core cable is 1.68 times lower than that of aluminum-core cable, with less energy consumption.

2.Good ductility: the extension rate of copper for electrical use is more than 30%, while that of aluminum alloy is only 18%.

3.High Strength: The promising strength of copper is much higher than that of aluminum.At room temperature, the promising force of copper is 7~28% higher than that of aluminum.And the stress at high temperature, the difference between the two is greater.

4.Fatigue resistance: copper repeated bending is not easy to break, aluminum repeated bending is easy to break.In terms of elasticity index, copper is also about 1.7~1.8 times higher than aluminum.

5.Good stability, corrosion resistance: aluminum core is easy to oxidize and be corroded, copper core is relatively stable, strong oxidation resistance.

6.Large carrying capacity: copper core resistivity is low, so the copper core cable can pass the maximum current carrying capacity is 30% higher than the aluminum core.

7.Low heating temperature: under the same current, the calorific value of the copper core cable with the same cross section is much smaller than that of the aluminum core cable, making the operation safer.

8.Low power consumption: Due to the low resistivity of copper, it is obvious that the copper cable has a lower power loss than the aluminum cable.This is conducive to improving the efficiency of power generation and protecting the environment.

9.Oxidation resistance, corrosion resistance: copper core cable connector performance is stable, no accident due to oxidation.The unstable joint of aluminum core cable often causes accidents due to the increase of contact resistance and heating caused by oxidation.As a result, the accident rate is much greater than the copper core cable.

10.Convenient construction: the copper core is flexible and the allowable bending radius is small, so it is convenient to turn and easy to pipe;Copper core fatigue resistance, repeated bending is not easy to break, so convenient wiring;The copper core has high mechanical strength and can bear large mechanical tension, which brings great convenience to the construction laying and also creates conditions for mechanized construction.

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.

Safe Use of Cable: How to Prevent Wires and Cables from Catching Fire Due to Overload of Wres

Wire and cable in the process of operation, due to the existence of resistance will be heated.The resistance of the wire is generally very small, and its heating power can be expressed by the formula Q =I^2R.Q =I^2R indicates that: for a section of wire in use (R has been basically constant), the greater the current through the wire, the greater the heating power;If the current constant, then the wire heating power is constant.The heat released during operation will be absorbed by the wire itself, thus causing the temperature of the wire to rise.

Although the wire is constantly absorbing the heat released by the current in the process of operation, its temperature will not rise unlimitlessly.Because while the wire is absorbing heat, it’s also releasing heat into the outside world, and it turns out that the temperature of the wire increases gradually when it’s energised until it stays at a certain point.At this constant point, the heat absorption and release power of the wire are the same, and the wire is in thermal equilibrium.There is a limit to the ability of wires to withstand higher temperatures, and operating above a certain maximum temperature may be hazardous.This maximum temperature also corresponds to a certain maximum current, above which the wire is overloaded.Overloading of the wire directly causes the temperature of the wire itself and the objects nearby to rise.Rising temperatures are the most direct cause of such fires.

Overload causes the insulation layer between the two wires to be damaged, causing a short circuit, burning down the equipment and causing a fire.The double wire is separated by the insulation layer between them. Overload makes the insulation layer soften and destroy, which leads to the direct contact between the two wires, causing short circuit and burning equipment.At the same time, the high temperature generated by the large current at the moment of short circuit causes the line to catch fire and fuse, and the molten beads generated fall to the combustible material to cause the fire.Overload temperature rise can also directly ignite nearby combustibles.The heat transfer of overload wire raises the temperature of combustibles nearby, and it is possible for combustibles nearby with low ignition point to ignite and cause fire.In the storage of flammable goods in the warehouse and the use of easy, combustible decoration of the building, this risk is particularly prominent.

 

The overload also puts the connections in the line under conditions of overheating, which speeds up the oxidation process.Oxidation makes the connection point produce a thin layer of oxide film, which is not easy to conduct electricity. The oxide film increases the resistance between the contact points, resulting in ignition and other phenomena, causing fire.So, how to prevent the overload of wires and cables caused by fire?

In the process of line design, we should accurately check and ratify the capacity of the site, fully consider the possibility of new capacity in the future, and choose the right type of wire.Large capacity, should choose a thicker wire.Circuit design and reasonable selection are the key steps to prevent overload.If the design selection is not correct, it will leave a congenital hidden danger that is difficult to rectify.Some small projects, places not serious design and selection.Arbitrary selection and laying of lines, this is very dangerous.New electrical appliances, electrical equipment should be fully considered the bearing capacity of the original line.If the original line does not meet the requirements, it should be re-designed and transformed.

The line should be laid by qualified electricians according to the relevant specifications.The laying conditions of the circuit directly affect the heat dissipation of the conductor.Generally speaking, the line laying should not pass through easy and combustible materials and stacking, which will lead to poor heat dissipation of the wire and heat accumulation, resulting in the possibility of igniting combustible items around, and increasing the risk of fire caused by overload;The lines laid in the ceiling of the decoration of public entertainment places should be protected by steel pipes to separate the ceiling from the line. In the case of overload and short circuit, even if there are molten beads, they will not fall off to avoid fire.

Strengthen electricity management, avoid disorderly wiring, random wiring, careful use of mobile socket.Disorderly wiring, random wiring, the use of mobile socket is actually in a certain line to add electrical equipment, increase the current and may cause overload.The jack of the mobile socket is obviously more than the fixed socket on the wall. If too much electrical equipment is used on the mobile socket, the original line must be difficult to bear.Separate lines should be set for high-power equipment and electrical appliances, and mobile sockets should not be used as wiring sources.

Accelerate the renewal and transformation of old lines to eliminate fire hazards.Old enterprises, old residential areas and other units, due to the use of a long time, many lines have been aging, more than the service life.Even if the carrying capacity of some lines is not large, the aging lines are difficult to bear such carrying capacity, and also have the risk of overload.Especially in the old residential areas, the lines have long been aging, but with the improvement of people’s living standards and the increase of household appliances, the electricity consumption is still rising year by year, which is really worse.For old lines, we should timely supervise and coordinate, and promote their rectification as soon as possible, so as to eliminate fire hazards and ensure safety.

Buy Wire and Cable These Knowledge Points You Want to Know!

                                                      First tip: first understand the meaning of Aerial Bundled Cable (ABC) BS 7870 Standard

Use code: A installation line, B cloth wire, C Marine cable, R flexible cable, K control cable, N agricultural cable, M coal cable, U mine cable, JK overhead cable;ZC flame-retardant cable, NH fire-resistant cable, WD low smoke free halogen cable.

Characteristic code: B flat, R soft, C heavy duty, Q light duty, Z medium duty, S twin type, P shield, L aluminum core, V insulated polyvinyl chloride, YJ crosslinked J polyethylene, H welding machine.For example, WDZN-BYJ stands for polyethylene insulated low smoke no halogen flame retardant wire, its rated voltage is 450/750V.

 

                                                             Second recruit: choose PVC Sheathed Power Cable according to the purpose

When choosing wires and cables, use, laying conditions and safety should be considered.Such as:

According to the different electrical appliances, optional wire, power cord, twisted pair, red and black wire, video cable and so on.

According to the different uses, can choose power cable, fire cable, overhead insulated cable, control cable, etc.

According to different laying conditions, cross-linked cable, armoured cable, aluminum alloy cable, anti-corrosion cable and so on can be selected.

According to the safety requirements, can choose flame retardant cable, halogen-free flame retardant cable, fire resistant cable, etc.

 

 

                                                                            Third recruit: choose cross-sectional area namely specification

The specifications of home wiring have dozens of specifications such as BV2.5, BV1.5, BV4, BV6;BV is a national standard code, and the numbers are our traditional square number of wires. In general, the wires are used as:

1,The 6 square meters are suitable for households, because the demand for land used by households is high.

2, 4 square suitable for the kitchen switch socket separate line and air conditioning water heater line, after all, these are power consumption, the wire specification can carry more electrical appliances as far as possible;

3, 2.5 square wire used in the common switch, socket and lighting main line;

4, 1.5 square for lighting control circuit switch, etc.

The specification of wire and cable is not the bigger the better, choose the right one is good, the specification is too large will only waste electricity

                                                                              Fourth recruit: choose brand heavy service

The safety and reliability of wire and cable should be guaranteed as the common wire in life.Therefore, when purchasing wires and cables, we should start from our own actual situation and buy reliable old brands. We should consider more from the practical aspect, so that quality, price and after-sales service can be guaranteed.

Jin Hautai, Dongguan wire and cable dealer, I hope this article can help you.

National Standard Cable

In today’s wire and cable market, product quality levels are uneven, and production companies are mixed. Many Party A simply uses price as the procurement standard, which breeds a market for substandard products. So that when users are faced with different prices of “national standard cables”, they will be at a loss, not knowing how to identify and buy national standard cables. Today’s article mainly introduces the standards and identification of national standard cables. What kind of cables are produced in accordance with national standards? How to distinguish and distinguish cables of different qualities? What kind of quality is “enterprise standard/non-standard”, “market national standard” and “protected resistance national standard”? No matter you are selling cables , Or purchasing, I believe it will be helpful to you.

What is Aerial Bundled Cable (ABC) HD 626 S1 Standard

The national standard cable, literally understood, is the wire and cable produced in strict accordance with the national standard. my country has clear regulations on the appearance, mechanical strength, insulation of the sheath, pressure resistance, wire resistance and other aspects of the cable. Different types of cables have different national standards, mainly as follows:

Irradiation cross-linked power cable (0.6/1KV) executive standard: GB/T12706.1-2008

Medium voltage cross-linked cable (6/6KV-26/35KV) executive standard: GB/T12706.2-2008

High voltage cross-linked cable (64/110KV) executive standard: GB/T 11017-[/B]2002

Control cable (450/750V) executive standard: GB9330-88

Aluminum stranded wire and steel core aluminum stranded wire (0.6/1KV) executive standard: GB/T 1179-1999

How to identify the (ABC) SANS 1418 Standard

  1. It depends on

See if there is a quality system certification; see if the certificate is standardized; see if there is a factory name, site, inspection stamp, and date of production; see if there are trademarks, specifications, voltages, etc. printed on the wires. It also depends on the cross-section of the copper core of the wire. The high-quality copper is bright in color and soft in color, otherwise it is inferior.

  1. Try

It is recommended to bend a wire head repeatedly by hand. Anything with soft hand feeling, good fatigue resistance, elastic plastic or rubber hand feeling and no cracks on the wire insulator is the best product.

  1. Weighing

Good quality wires are generally within the specified weight range. For example, the commonly used plastic insulated single-strand copper core wire with a cross-sectional area of ​​1.5mm² has a weight of 1.8~1.9 kg per 100 meters; a 2.5mm² plastic insulated single-strand copper core wire has a weight of 3~3.1 kg per 100 meters; poor quality The weight of the wire is insufficient, or the length is not enough, or the copper core of the wire is too much impurity

  1. Look at copper

The copper core of the qualified copper core wire should be purple-red, shiny, and soft to the touch.

The fake and inferior copper core wires are purple-black, yellowish or white, with many impurities, poor mechanical strength, poor toughness, and will break with a little force, and there are often broken wires in the wires.

When checking, you only need to peel off the wire 2cm, and rub a piece of white paper on the copper core. If there are black substances on the white paper, it means that there are more impurities in the copper core. In addition, the insulating layer of fake wires seems to be very thick, but in fact, most of them are made of recycled plastics. Over time, the insulating layer will age and cause leakage.

  1. Look at the price.

Due to the low production cost of counterfeit and shoddy wires, vendors often sell them at low prices under the guise of low prices and good quality when selling.

“Non-standard/enterprise standard/market national standard” and “protected resistance national standard”?

When many sales companies are asked whether they are national standard cables, they often hear words like “market national standard” and “resistance protection national standard”. Many people have a little understanding. What do these vague words mean?

National standard for resistance protection: The cable is used to energize, and the resistance value of the conductor directly affects the conductivity. If the conductor resistance is too large, the conductivity will be poor, and a large amount of heat will be generated when a large current passes, which will cause a fire. At the same time, due to the large resistance, heat will be generated and the power will be consumed inaction.

The resistance-protected cable is to ensure that the resistance value of the cable is in compliance with the national standard, but it does not guarantee that the component materials of the cable are produced in full accordance with the national standard, such as the number of conductor squares, insulation, and sheath. To put it bluntly, it means that the manufacturer can achieve safe use of cables under the premise of reducing material costs through various technological innovations (or means).

Note that two words are used here: innovation and means. Innovation refers to reducing costs through technological innovation, such as current aluminum alloy conductors, special-shaped conductors, etc., such cables reduce the price on the premise of ensuring safe use. Some manufacturers use some illegal means to reduce costs, such as using second-generation materials, reducing conductor purity, etc. Even if the resistance value of such a cable is within the standard range, its use is extremely unsafe. The cable must be checked again and again.

Classification of home improvement wires

BV wire, full name copper core PVC insulated wire, referred to as plastic copper wire. That is, a general-purpose single-core hard conductor non-sheathed cable with a diameter of 1mm or more.
It is suitable for wires used in power installations, household appliances, meters and telecommunication equipment with AC voltage of 450/750 and below. It has the characteristics of acid and alkali resistance, oil resistance, moisture resistance, mildew resistance, and long service life. Because it has a certain degree of hardness, it is more convenient in straightening and folding corners.


BVR wire is generally a wire twisted together by 19 copper wires with a diameter of less than 1mm. It is a copper core PVC insulated flexible wire.
The letter B stands for wiring (for example: make an indoor power line and tack it on the wall);
The letter V-polyvinyl chloride plastic sheath (a V stands for one layer of insulation and two V stands for double insulation), which is a plastic insulation layer.


L stands for aluminum wire, without L stands for copper wire.
The letter R stands for soft wire. To be soft, it means to increase the number of conductors and reduce the diameter of each wire.
It is suitable for the occasions where flexibility is required for wiring and the rated voltage is lower than 450/750 with slight movement. When multiple pipes are pierced at the same time, due to the low hardness, it is easy to turn and convenient for construction. Compared with the hard wire, the production is more complicated, and the high-frequency circuit has a larger carrying capacity than the hard wire.
Classification of common specifications and models of wires
Common specifications of wires are 1.5 square, 2.5 square, 4 square, 6 square, and 10 square. The square of the wire is square millimeters, which is the size of the cross-sectional area of ​​the wire.