First, the cable concept
[electric cable; power cable] is usually a cable-like cable made up of several or several sets of wires [at least two in each group], each set of wires is insulated from each other and often twisted around a center , the entire outer bread has a highly insulating covering
Wire and cable refers to materials used in power, communications, and related transmission applications. There are no strict boundaries between "wires" and "cables." Generally, a product with a small number of cores, a small product diameter, and a simple structure is called a wire, a non-insulated wire is called a bare wire, and the other is called a cable; a conductor having a large cross-sectional area (greater than 6 square millimeters) is called a large wire. Small (less than or equal to 6 square millimeters) is called a small wire, and insulated wire is also called a wire.
Wire and cable mainly includes bare wires, electromagnetic wires and insulated wires for electrical appliances, power cables, communication cables and optical cables. Cables include power cables, control cables, compensating cables, shielded cables, high temperature cables, computer cables, signal cables, coaxial cables, fire resistant cables, marine cables, and the like. They are composed of multiple strands of wire used to connect circuits, electrical appliances, and the like.
Second, wire and cable naming
The complete naming of wires and cables is often complicated, so people sometimes use a simple name (usually a category name) in combination with the model specification instead of the full name, such as "low voltage cable" for all plastic insulated power of 0.6/1kV class. cable. The wire and cable type spectrum is relatively perfect. It can be said that as long as the standard model specifications of the wire and cable are written, the specific product can be specified, but what is its complete name?
The naming of wire and cable products has the following principles:
1. Content included in the product name
- Product application or size class name
- product structure materials or types;
- Important or additional features of the product
Basically named in the above order, sometimes in order to emphasize important or additional features, the features are written before or before the corresponding structure description.
2. the order of structure description
The product structure is described from the inside to the outside: conductor -> insulation -> inner sheath -> outer sheath -> armored type.
In the case of no confusion, some structural descriptions are written or abbreviated. For example, aluminum conductors are not allowed in automobile wires and cords, so conductor materials are not described.
Flame-retardant copper core XLPE insulated steel tape armored PVC sheathed power cable with rated voltage of 8.7/15kV (too long!)
"Rated voltage 8.7/15kV" - use occasion / voltage level
"Flame retardant" - the characteristics of emphasis
"Copper core" - conductor material
"Crosslinked Polyethylene Insulation" - Insulation
"Steel belt armor" - armor layer material and type (double steel belt gap wrapping)
"PVC sheath" - inner and outer sheath material (the inner and outer sheath materials are the same, save the inner sheath material)
"Power Cable" - the broad name of the product
The corresponding model is written as ZR-YJV22-8.7/15. The model is written as described below.
Third, wire and cable models
The model and sequence of wire and cable are as follows:
[1: Category, use] [2: Conductor] [3: Insulation] [4: Inner sheath] [5: Structural features] [6: Outer sheath or derivative]-[7: Use characteristics] 1-5 items And the seventh item is represented by a pinyin letter, the polymer material is represented by the first letter of the English name, each item can be 1-2 letters; the sixth item is 1-3 numbers.
The omission principle in the model: copper is the main conductor material used in wire and cable products, so the copper core code T is written, except for bare wires and bare conductor products. Bare wire and bare conductor products, power cables, and electromagnetic wire products do not indicate large class codes. Wires and cables for electrical equipment and communication cables are not listed, but subcategories or series codes are listed. Item 7 is a mark for various special use occasions or additional special use requirements, and is marked with a pinyin after "-". Sometimes in order to highlight the item, write this item to the front. Such as ZR- (flame retardant), NH- (refractory), WDZ- (low smoke and halogen free, corporate standards), -TH (for hot and humid areas), FY- (anti-termites, corporate standards).
Digital marker armor layer outer layer or outer sheath
- 2 double steel strip PVC jacket
- 3 thin round wire polyethylene jacket
- 5 wrinkles (rolling) steel strip
- 6 double aluminum (or aluminum alloy) belt
Fourth, wire and cable applications
The wire and cable products used in the power system mainly include overhead bare wires, bus bars (bus bars), power cables (plastic cables, oil-paper cables (substantially replaced by plastic power cables), rubber cables, overhead insulated cables), and branch cables. (Replaces some busbars), magnet wires, and electrical equipment, wires and cables for power equipment.
Information transmission system
The wire and cable used for the information transmission system mainly includes local telephone cable, television cable, electronic cable, radio frequency cable, optical fiber cable, data cable, electromagnetic wire, power communication or other composite cable.
Mechanical equipment, instrumentation system
This part is used in almost all other products except for overhead bare wires, but mainly power cables, magnet wires, data cables, instrumentation cables, etc.
Five, wire and cable products
Bare wire and bare conductor products
The main features of this product are: pure conductor metal, no insulation and sheath layer, such as steel core aluminum stranded wire, copper-aluminum busbar, electric locomotive line, etc.; processing technology is mainly pressure processing, such as smelting, rolling, pulling System, stranding/tightening stranding, etc.; products are mainly used in suburbs, rural areas, user main lines, switch cabinets, etc.
The main features of this type of product are: extrusion (winding) insulation on the outer conductor, such as overhead insulated cable, or stranding (corresponding to the phase, neutral and ground of the power system), such as overhead insulated cables with two cores or more , or add a jacket layer, such as plastic / rubber sheathed wire and cable. The main process technologies include drawing, stranding, insulation extrusion (winding), cable-forming, armoring, and sheath extrusion. The different process combinations of various products have certain differences. The products are mainly used for transmission of strong electric energy in the transmission, distribution, transmission, transformation and power supply lines. The currents passing through are large (tens of amps to several thousand amps) and high voltages (220V to 500kV and above).
wire and cable for electrical equipment
The main features of this type of product are: wide variety of specifications, wide application range, use voltages of 1kV and below, and new products such as fire-resistant cables, flame-retardant cables, low-smoke halogen-free/low Smoke low halogen cable, termite resistant, mouse cable, oil/cold resistant/temperature resistant/wear resistant cable, medical/agricultural/mineral cable, thin wall wire, etc.
communication cable and fiber (a brief introduction)
With the rapid development of the communication industry in the past two decades, the products have also experienced phenomenal development speed. From the simple telephone telegraph cable in the past to thousands of pairs of cable, coaxial cable, optical cable, data cable, and even a combination of communication cables. The structure size of such products is usually small and uniform, and the manufacturing precision is high.
electromagnetic wire (winding wire)
Mainly used in various motors, instruments and so on.
Derivatives/new products for wire and cable
The derivative/new products of wire and cable are mainly due to the requirements of application, application requirements, equipment convenience and equipment cost reduction, and adopt new materials, special materials, or change product structure, or improve process requirements, or will be different. Variety of products are produced in combination.
Use different materials such as: flame retardant cable, low-smoke halogen-free/low-smoke low-halogen cable, termite-proof, mouse-proof cable, oil/cold/temperature resistant cable, etc.
Change product structure such as: fire resistant cable;
Improve process requirements such as: medical cables;
Combination products such as: OPGW;
Easy to install and reduce equipment costs such as: prefabricated branch cables.
Six, cable wire Q & A
Q. What types of commonly used wires and cables are used according to their purposes?
A: According to the application, they can be divided into bare wires, insulated wires, heat-resistant wires, shielded wires, power cables, control cables, communication cables, and RF cables.
Q. What kinds of insulated wires are available?
A: There are several types of insulated wires: polyvinyl chloride insulated wire, PVC insulated cord, nitrile polyvinyl chloride mixture insulated cord, rubber insulated wire, agricultural underground buried Aluminum core plastic insulated wire, rubber insulated cotton yarn textile cord, PVC insulated nylon sheathed wire, PVC insulated cord for power and lighting, etc.
Q. What kind of occasion is the cable tray suitable for?
A: The cable tray is suitable for general industrial and mining enterprises to lay power cables and control cables indoors and outdoors, and can also be used for erection indoors and outdoors in telecommunications, radio and television departments.
Q. What are the cable accessories?
A: Commonly used electrical accessories include cable terminal junction box, cable intermediate junction box, connecting pipe and terminal block, steel plate wiring slot, cable tray and so on.
Q. What is the cable intermediate connector?
A: The device that connects the cable and the cable conductor, the insulation shielding layer and the protective layer to make the cable line connection is called the cable intermediate connector.
Seven, the cable model consists of eight parts
use code - not marked as power cable, K is the control cable, P is the signal cable;
insulation code -Z oil-impregnated paper, X rubber, V polyvinyl chloride, YJ cross-linked polyethylene
Conductor material code - not marked as copper, L is aluminum;
inner sheath code - Q lead package, L aluminum package, H rubber sleeve, V PVC sheath
the derived code -D does not drip, P dry insulation;
the outer layer code
special product code -TH wet tropical, TA dry tropical;
rated voltage - unit KV
Eight, the problem with the cable model
SYV: solid polyethylene insulated RF coaxial cable
SYWV (Y): physical foaming polyethylene insulated cable TV cable, video (RF) coaxial cable (SYV, S YWV, SYFV) for closed-circuit monitoring and cable TV engineering
SYWV (Y), SYKV cable TV, broadband network dedicated cable structure: (coaxial cable) single oxygen-free round copper wire + physical foamed polyethylene (insulation) + (tin wire + aluminum) + polyvinyl chloride (polyethylene) )
Signal control cable (RVV sheathed wire, RVVP shielded wire) is suitable for building intercom, anti-theft alarm, fire protection, automatic meter reading and other projects.
RVVP : Copper core PVC insulated and sheathed PVC sheathed flexible cable Voltage 300V/300V 2-24 core Application: instrument, instrument, intercom, monitoring, control installation
RG: physical foamed polyethylene insulated access network cable for transmitting data analog signals in coaxial fiber hybrid network (HFC)
KVVP: PVC sheathed braided shielded cable Uses: signal transmission, control, measurement of electrical appliances, instruments, power distribution devices
RVV (227IEC52/53) PVC insulated flexible cable Uses: household appliances, small power tools, instruments and power lighting
AVVR PVC sheathed flexible cable for installation
SBVV HYA data communication cable (indoor and outdoor) for telephone communication and connection of radio equipment and wiring box wiring for telephone wiring network
RV, RVP PVC insulated cable
RVS and RVB are suitable for household appliances, small power tools, instruments, meters and power lighting connection cables.
BV, BVR PVC insulated cable Uses: Suitable for electrical instrumentation equipment and power lighting fixed wiring
RIB speaker cable (fever line)
KVV PVC insulated control cable Uses: Signal transmission, control and measurement of electrical appliances, instruments and power distribution equipment
SFTP twisted pair transmission telephone, data and information network
UL2464 computer cable
VGA display line
SYV coaxial cable Transmitting RF signals in wireless communication, broadcasting, monitoring system engineering and related electronic equipment (including integrated coaxial cable)
SDFAVP, SDFAVVP, SYFPY coaxial cable, dedicated to elevators
JVPV, JVPVP, JVVP copper core PVC insulated and sheathed copper wire braided computer control cable
Nine, metal materials for cables
Conductivity is second only to silver, thermal conductivity is second only to gold and silver; corrosion resistance, non-magnetic, good plasticity, easy to weld, and widely used. Copper alloys mainly improve the wear resistance, corrosion resistance and mechanical properties of copper.
The metal has the highest conductivity and thermal conductivity, has good corrosion resistance and oxidation resistance, and is easy to weld; it is mainly used for plating and cladding; it is mainly used as high temperature resistant wire and (note: according to the principle of skin effect) Frequency communication cable conductor.
good corrosion resistance, general mechanical strength, good plasticity and small specific gravity. The disadvantage is that the tensile strength is low and it is not easy to weld. Aluminum alloys mainly improve the mechanical strength, heat resistance and weldability of aluminum.
Used as a high temperature resistant wire.
It is often used as a reinforcing material for composite conductors, such as steel core aluminum wire, copper clad steel, aluminum clad steel wire, and the like.
Used as a coating for steel/steel strip/iron conductors to prevent corrosion.
Used as a wire/copper wire coating to prevent corrosion and facilitate copper wire bonding.
Ten, cable storage
If the cable is to be stored for a long time, the cable is placed in:
Under the eaves. The standard LAN cable can be used only when the cable is not directly exposed to sunlight or high temperature. It is recommended to use the pipe.
The outer wall. Avoid direct sunlight on the wall and human damage.
In the pipe (plastic or metal). In the pipeline, pay attention to the damage of the plastic pipe and the heat conduction of the metal pipe.
Suspended application / overhead cable. Consider the drooping and pressure of the cable. Which type of bundling is intended? Is the cable exposed to direct sunlight?
Lay directly in the underground cable trench, this environment is the smallest control area. Cable trench installations should be regularly checked for dryness or humidity.
Underground pipelines. In order to facilitate future upgrades, cable replacement and isolation from surface pressure and surrounding environment, auxiliary piping is isolated, and auxiliary piping is a better method. But don't expect the pipeline to remain dry forever, which will affect the choice of cable type.
eleven, What are the common cable faults?
Common faults in cable lines are mechanical damage, insulation damage, insulation moisture, insulation aging deterioration, overvoltage, cable overheating faults, etc. When the above-mentioned fault occurs on the line, the power supply of the faulty cable should be cut off, the fault point should be found, the fault should be inspected and analyzed, and then repaired and tested. The cut-off can be resumed after the fault is eliminated.
twelve, What are the requirements for the safety of buried cable lines?
The safety requirements for buried cable lines are:
When the cable lines cross each other, the high voltage cable should be below the low voltage cable. If one of the cables is protected by a pipe within 1 m before and after the intersection or separated by a partition, the minimum allowable distance is 0.25 m.
When the cable is close to or intersects with the heat pipe, if there is insulation, the minimum distance between parallel and cross is 0.5m and 0.25m respectively.
When the cable crosses the railway or the road, it should be protected by a pipe. The protection pipe should extend beyond the track or road surface by 2m.
The distance between the cable and the building foundation should 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 be outside the building's scattered water.
The distance between the cable directly buried in the ground and the grounding of the general grounding device should be 0.25~0.5m; the buried depth of the cable buried directly in the ground should not be less than 0.7m, and should be buried under the frozen soil layer.
thirteen,China's wire and cable industry development overview
The wire and cable industry is the second largest industry in China after the automotive industry, with product product satisfaction rates and domestic market share exceeding 90%. In the world, the total output value of China's wire and cable has surpassed that of the United States, becoming the world's largest wire and cable producer. Along with the rapid development of China's wire and cable industry, the number of new enterprises has been rising, and the overall technical level of the industry has been greatly improved.
The sustained and rapid growth of China's economy has provided huge market space for cable products. The strong temptation of the Chinese market has made the world focus on the Chinese market. In the short period of reform and opening up, China's cable manufacturing industry The huge production capacity that has been formed has made the world look impressive. With the continuous expansion of China's power industry, data communication industry, urban rail transit industry, automobile industry and shipbuilding industry, the demand for wire and cable will also grow rapidly. In the future, the wire and cable industry has great potential for development.