China Zhenglan Cable Technology Co., Ltd Company News

1. Application of control cable: it is mainly used for transmitting control, measuring signal, etc. The control cable is suitable for long-distance operation, control furnace, signal and protection measuring circuit of mainstream and AC 50Hz, rated voltage 450 / 750V, 600 / 1000V and below industrial and mining enterprises and modern high-rise buildings. As a connecting line between various electrical instruments and automatic instruments, it plays a role in transmitting various electrical signals and ensuring the safe and reliable operation of the system. 2. The control cables can be divided into ordinary control cables, fire-retardant (Zr) control cables, fire-resistant (NH), low smoke and low halogen (DLD), low smoke and zero halogen (DW), high flame-retardant (gzr), temperature resistant, cold resistant control cables, etc. according to the work category. 3. main shielding types of control cable: copper wire woven shielding, copper tape shielding, aluminum plastic composite tape shielding The control cable is used to transmit control signals, with a large number of cores. According to the standard, there are 61 cores, but it can also be produced according to the user's requirements. Operating temperature of control cable: rubber insulation is 65 ° C, PVC insulation is 70 ° C and 105 ° C. The control cables used in computer system are generally PVC, PE, XLPE and fluoroplastic insulated products The recommended allowable bending radius of cable is as follows: The unarmoured cable shall not be less than 6 times of the outer diameter of the cable; Armored or copper tape shielded cable shall not be less than 12 times of the outer diameter of the cable; Shielded flexible cable, not less than 6 times of cable outer diameter. Precautions for installation and wiring of control cable: 1. Under the eaves. The standard LAN cable can be used only when the cable is not directly exposed to sunlight or ultra-high temperature. It is recommended to use pipes. Ultraviolet (UV) - do not use cables without UV protection in direct sunlight. 2. On the outer wall. Avoid direct sunlight on the wall and man-made damage. Heat - the temperature of a cable in a metal conduit or trunking is very high, and many polymeric materials will reduce their service life at this temperature. 3. In pipes (plastic or metal). For example, in the pipe, pay attention to the damage of plastic pipe and the heat conduction of metal pipe. Mechanical damage (repair cost) - the repair of optical cable is very expensive. At least two terminations are required at each breakpoint. 4. Suspended application / overhead cable. Consider cable sag and pressure. Whether the cable is directly exposed to sunlight. 5. It is directly laid in the underground cable trench, and this environment is the smallest in the control range. The installation of cable trench shall be checked regularly for the degree of dryness or humidity. Grounding - if the shield of the control cable needs to be grounded, the corresponding standards must be followed. 6. Underground pipeline. In order to facilitate future upgrading, cable replacement and isolation from surface pressure and surrounding environment, auxiliary pipeline is a better method. But don't expect the pipe to stay dry forever, which will affect the selection of cable types. Water - the moisture in the LAN twisted pair cable increases the capacitance of the cable, reducing the impedance and causing near end crosstalk problems.    

(1) When the cable leaves the factory, both ends of it are sealed with plastic sealing sleeve.But in the construction process, after using a part, the remaining part of the wire head is simply wrapped, usually open air and no sealing measures, for a long time, water vapor will infiltrate the cable;   (2) When laying cables, it is necessary to cross roads, Bridges, culverts, etc.However, due to weather and other reasons, the cable trench is often filled with water, and occasionally the cable head is immersed in water.Poor sealing makes it easy for water to enter the cable.In addition, the outer sheath and even the steel armoring will be scratched when pulling and penetrating the pipe.   (3) After the completion of cable laying, the cable head was not made in time due to the restrictions of site construction conditions, so that the unsealed cable fracture was exposed to air for a long time, or even immersed in water, so that a large amount of water vapor entered the cable.   (4) In the process of making the cable end (including the terminal head and intermediate joint), due to the negligence of the construction personnel, there is no contact or immersion of the cable end in water;   (5) In the normal operation of the cable, when breakdown occurs for some reason, the water in the cable trench will enter the cable along the fault point, the cable insulation will be seriously damaged, and water will also cause the cable.    

1) External force damage. According to the operation analysis in recent years, a lot of cable faults are caused by mechanical damage. For example: the cable laying and installation are not standardized, which is easy to cause mechanical damage; the civil construction on the directly buried cable is also easy to damage the cable in operation. 2) The insulation is damp. This kind of situation is also very common, generally occurs in the direct burial or the cable joint in the pipe. For example, if the cable joint is not qualified or made in humid climate, it will cause water or steam to enter the joint and form water branches under the action of electric field, which will gradually damage the insulation strength of the cable and cause failure. 3) Chemical corrosion. When cables are directly buried in the areas with acid and alkali effects, the armour, lead skin or outer protective layer of cables will be corroded, and the protective layer will suffer from chemical corrosion or electrolytic corrosion for a long time, which will cause the failure of protective layer, insulation reduction and cable failure. 4) Long term overload operation. In overload operation, due to the thermal effect of current, when the load current passes through the cable, it will inevitably cause the conductor to heat up. At the same time, the skin effect of charge, eddy current loss of steel armor and insulation medium loss will also generate additional heat, thus increasing the cable temperature. Long term overload operation, too high temperature will accelerate the aging of the insulation, and even the insulation is broken down. Especially in the hot summer, the temperature rise of the cable often causes the cable insulation weak place to be first broken down, so in summer, the cable fault is particularly many. 5) Cable connector failure. The cable joint is the weakest link in the cable line, and the cable joint fault caused by the direct fault of personnel (poor construction) often occurs. In the process of making cable joints, if there is an original network such as the joints are not tightly crimped and the heating is not sufficient, the insulation of the cable head will be reduced, which will lead to accidents. 6) Environment and temperature. The external environment and heat source of the cable will also cause the cable temperature to be too high, insulation breakdown, even explosion and fire.    

The armor provides mechanical protection against crushing forces. Armor also can serve as an Earth Continuity Conductor (ECC). There are different types of armors available: metallic or non-magnetic Alumimium, Steel wire/strip.But not for a single type can be used in all occasions.   When an electric current passes through a cable it produces a magnetic field (the higher the voltage the bigger the field). The magnetic field will induce an electric current in steel armor (eddy currents), which can cause overheating in AC systems. The non-magnetic aluminum armor prevents this from happening.   What type of armor is suitable for single core cable? Non Magnetic Material’s armoring for 1Ph System: This is not so however for a single-core cable, where eddy-current heating would occur if a magnetic material was used for the armoring. The material has to be non magnetic for armoring as in this case of return current is not passing through the same cable. Hence it will not cancel the magnetic lines produced by current. These magnetic lines which are oscillating in case of A.C. systems will give rise to eddy currents in magnetic armoring and hence armoring will become hot, and this may lead to failure of the cable. Hence Single core cables for use on A.C systems are armored with single layer of nonmagnetic (Aluminum) material. · Armoring is Mostly following Type · STA – Steel tape armor, used in multi-core cables (non-magnetic), · AWA – Aluminum wire armor, used in single-core cables (non-magnetic). · Tinning or galvanizing is used for rust prevention. Phosphor bronze or tinned copper braid is also used when steel armor is not allowed. · As strip construction is economical, the manufacture always provides steel strip armoring unless wire armoring is specified. · As per IS: 1554 Round Wire armoring is provided in cable where calculated diameter under amour is upto13mm. Above this the amour is either steel wire or steel strip of size 4.00X0.80mm.   Zhenglan Cable Technology Co., Ltd can do steel tape armor, steel wire armor, aluminum wire armor. Welcome your inquiry.    

How to judge the quality of fire-retardant wires & cables? 1. Color 1) Color requirements: the color of the sign shall be able to confirm that it follow or approaches a certain color specified in GB6995.2-86 wire and cable identification mark part 2: standard color. 2) Clarity: the color of the sign shall be easy to identify or recognize. 3) Scratch resistance: the mark shall be scratch resistant, and the color after wiping shall be basically unchanged. 2. Number 1) Color requirements: the carrier shall be the same color, and the color of all identification numbers shall be the same color. The carrier color shall be obviously different from the mark color, and it shall be able to confirm that it follow or is close to a certain color specified in GB6995.2-86. 2) Clarity: the number sign shall be clear and the writing shall be clear. 3) Rub resistance: the digital sign shall be rub resistant, and the sign after wiping shall remain unchanged. 3. Imprint mark 1) Form: the embossed mark shall be in the form of embossing or intaglio printing and directly imprinted on the carrier. 2) Clarity: the handwriting of the imprinted mark shall be clear or easy to recognize. 4. Sign line or band 1) Mark line: the mark line used to identify the origin of wires and cables shall be registered according to relevant regulations, and its color can be single color or combination color. 2) Sign belt: the sign belt is printed with words, letters, symbols and other marks, indicating the manufacturer of wires and cables, product voltage level, model, specification, trademark and so on. 3) Clarity: the color of the whole sign line shall be consistent, and the boundary between the two colors in the combined color shall be clear. The color of the sign line and the mark on the sign belt shall be clear and distinguishable. 4) Fastness: when washing with gasoline or other suitable solvent, the color of the mark shall remain unchanged.  

When we need to choose a kind of Low voltage (0.6/1kv) Cables in a project, usually we have to make a decision between the PVC insulated cable and XLPE insulated Cable, in order to make the right choice, you need to know the differences between the two kinds most popular cables. So let's see the differences in the following aspects:   1. Maximum working temperature of conductor: PVC insulated Cable is 70 Centigrade, XLPE insulated Cable is 90 Centigrade. 2. Maximum short (lasting less than 5 seconds) temperature: PVC insulated Cable is 160 Centigrade, XLPE insulated Cable is 250 Centigrade. 3. Service life: Usually, the XLPE insulated cable is longer than PVC insulated cable. 4. Price: Usually, the XLPE insulated cable price is higher than PVC insulated cable. 5. Water Proof Performance in Application Environment: PVC insulated cable is better than the XLPE insulated cable. 6. Environment Protection aspect: For XLPE is not containing chlorine which will release toxic gases once burn, so XLPE insulated Cable is environment friendly compared with PVC insulated Cable. 7. Conclusion: In a long run, the XLPE insulated Cable is better than PVC insulated Cable, but the price is a little higher, but if we take all factors in to consideration(such as environment protection, service life, safety and so on), XLPE insulated cable has a high cost-performance.   At last, there is a question left for you, it is difficult to distinguish the PVC and XLPE from appearance with a naked eyes, so do you know a easy way to distinguish the PVC and XLPE in the Cable?   Welcome to send your inquiry or questions about PVC or XLPE Cables to worldmarket@zhenglancable.com; You also can visit our web www.zhenglancable.com to get more cable information we manufactured and sold.