Difficulties in locating cable faults

Due to changes in the environment in which Power Cables are laid and the application of new materials for cables and their accessories in the cables, it is increasingly difficult to locate faults on the power cable site.
The difficulty of field cable fault location is mainly reflected in the fault location of directly buried power cable lines. At present, despite the relevant classic technical literature and advanced fault detectors, it is still available for high resistance faults in power cable lines. However, when using a professional cable fault locator to locate on site, sometimes you will encounter some special and difficult faults that cannot be located. For example, using a professional cable fault locator, part of the creepage flashover fault on the insulation surface of the medium voltage cross-linked power cable terminals and intermediate joints, and accurately determining the metal short-circuit fault, often appears powerless or powerless.

For common cable faults, you can use a cable fault locator purchased on the market to determine the location of the fault point within minutes or hours. However, when you encounter special difficult faults and the detection is not stable, you may need to call multiple cable fault detectors with different functions to repeat the test, and take turns to detect, locate, compare and confirm. The types of these fault devices mainly include various cable fault detectors designed, manufactured and developed based on the principles of bridging method and wave method. In this way, it may take several days or even longer to locate the fault. In this way, if you are lucky, you can determine the location of the fault point. If you are unlucky, the location of the fault point is still uncertain.
In northern China, the ground freezes in winter, and the directly buried cables fail at this time. The actual fault detection and handling process is actually a difficult task. First of all, the cable fault locator used must have high accuracy, and secondly, the corresponding personnel must have a clear understanding of the actual cable laying route. Although some cable fault detection instruments are now equipped with cable path testers, they must also be equipped with cable path testers. Only on-site personnel who understand the approximate laying path of the cable can cooperate to improve the positioning accuracy. The actual handling of cable faults sometimes depends on man-made three points and machine-made seven points.


At present, there are many manufacturers selling cable fault detection instruments on the market, and there are many types of detection instruments, but in fact, it is impossible to locate all cable faults. In actual use, the instrument usually can only effectively locate one or several types of faults, but still cannot do anything about some faults. The current electric power department hopes to spend a lot of money to purchase a universal cable fault tester with complete functions and high positioning accuracy (including rough and precise measurement points) to quickly and effectively solve all actual cable faults. But it’s actually hard to buy. There are various updated cable fault detectors on the market. However, the actual on-site inspection will still encounter some technical problems that cannot be located using the cable fault table. I think the reasons are mainly from two aspects: First, the various insulation, filling and wrapping materials used in the cable and its accessories are constantly being developed and updated, which leads to continuous changes in the types of cable failures. The other is that the market demand for cable fault detectors is limited, and related R&D personnel are scarce, resulting in a delay in the start of portable, high-precision, intelligent and multi-functional cable fault detectors. It is believed that with the advent of the smart grid era and the rapid development of Aerial Bundled Cable ASTM B231 Standard fault detection technology, the location of cable faults will become very simple and easy.

Factors Affecting Cable Performance and Placement in Wiring

Factors affecting Aerial Bundled Cable (ABC) SANS 1418 Standard and placement in the wiring six factors affecting cable performance:

  • Ultraviolet (UV)– Do not use cables without UV protection in direct sunlight.
  • Heat — The temperature of the cable in the metal tube or groove is very high, and many polymeric materials will degrade their service life at this temperature.
  • Water — moisture in a twisted-pair cable on a LAN can increase the capacitance of the cable, thereby reducing the impedance and causing near-end crosstalk problems.
  • Mechanical damage (repair cost)– Cable repair is very expensive and requires at least two terminations at each break point.
  • Grounding — If the shielding of the cable needs to be grounded, the appropriate standards must be complied with.
  • Total length of routing (not just between buildings)– Outdoor LAN twisted pair cables are used between buildings and the total length is limited to 90 meters. For 100Mbps or 1000Mbps networks, the paved distance cannot exceed this limit. If the laying distance is between 100 meters and 300 meters, optical cable should be chosen.

Is the cable placed in:

1.Under the eaves. 4/0 Aluminum Cable can only be used when they are not directly exposed to sunlight or ultra-high temperatures. Standard LAN cables are recommended.

  1. Exterior wall. Avoid direct sunlight exposure to the wall and man-made damage.
  2. In pipes (plastic or metal).If in pipes, pay attention to the damage of plastic pipes and the heat conduction of metal pipes.
  3. Hanging applications/overhead cables. Consider cable sag and pressure. What kind of binding do you plan to use? Whether the cable is exposed to direct sunlight.

  1. It is directly laid in the underground cable trench, which is the least controlled environment. The installation of cable trench should be checked regularly for dryness or humidity.
  2. Underground pipes. In order to facilitate future upgrades, cable replacement and isolation from surface pressure and surrounding environment, auxiliary pipe isolation, auxiliary pipe is a better method. But don’t expect the pipes to stay dry forever, which will affect the type of cable you choose.

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.

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.

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.

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.

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.

What should I pay attention to when buying Aerial Bundled Cable?

As the main carrier of power transmission,Aerial Bundled Cable  HD 626 S1 Standard is widely used in electrical equipment, lighting circuits, household appliances, etc. Its quality directly affects the quality of the project and the safety of consumers’ lives and properties. There are many types of wires in the market, and you must use the appropriate wires according to your own electricity load.
Some of the wires sold in the market are cheaper and some are more expensive, and some people tend to be cheaper first. However, cheap wires often have a lot of performance that does not meet the performance described by him, and they may bring themselves Many security risks. The production technology of the wire is not too high, and the raw materials are not too different. If it is too cheap, either it is cutting corners or the quantity is not enough. How to identify it. Let me tell you several methods that are easier to identify:

  • Take a look at the packaging. National standard wires are often made better, neat, and have a sense of quality when held in hand.
  • Open the package and take a look at the wires inside. The wire thickness (insulation thickness) of the national standard wire of 1.5-6 square meters is 0.7mm. If it is too thick, it is non-standard, and its inner core is definitely not enough. , You can pull the thread hard, the ones that are not easy to tear are generally the national standard.
  • Burn it with fire, the ones that are extinguished within 5s after leaving, and those with certain flame-retardant function are (ABC) ASTM B230 Standard .Look at the inner core, the higher the brightness of the inner core material (copper), the better the copper, and the brightness is uniform, shiny, and without layering. The national standard requires oxygen-free copper to be used in the core. Non-standard, such as black rod copper, may have potential accidents.
  • The thickness of the acsr core has certain national requirements, but it is not very strict. But you can’t go wrong a lot, it’s just a small error, which is generally invisible to the eye.
    The length, the country does not mandate that the rice must be beaten, but many manufacturers have also beaten the rice, and the rice that is beaten is not necessarily the national standard, but the general national standard generally does not. Non-standard rice harvesting is just a means.
  • The country stipulates that there must be a certain mark on the wire, and the maximum size will not exceed 500mm, and the next same mark will be printed. Generally, there are product trademarks, manufacturer names, and implementation standards.