Insulation material introduction of pvc insulated wire
What is PVC material?
Polyvinyl chloride, referred to as PVC in English, is a polymer formed by the polymerization of vinyl chloride monomer (VCM) in the presence of peroxides, azo compounds and other initiators or under the action of light and heat according to the mechanism of free radical polymerization. Vinyl chloride homopolymers and vinyl chloride copolymers are collectively referred to as vinyl chloride resins.
PVC is a white powder with an amorphous structure, the degree of branching is small, the glass transition temperature is 77~90°C, it begins to decompose at around 170°C, and it has poor stability to light and heat. Decomposition produces hydrogen chloride, and further automatic catalytic decomposition causes discoloration and rapid decline in physical and mechanical properties. Stabilizers must be added to improve heat and light stability in daily use.
What are the characteristics of PVC insulation?
1. High electrical performance. 2. Stable chemical properties. 3. Good machining performance. 4. No flame delay. 5. The price is cheap. 6. Large dielectric loss. 7. Poor heat resistance and cold resistance. 8. The operating temperature cannot be higher than 65°C. This kind of insulation is generally only used in the insulation layer of power cables of 6kV and below or as the outer sheath of the cable.
The role of PVC insulation in wire and cable
1) Reinforcing filling system: CPE is a non-self-reinforcing rubber, which requires a reinforcing system to achieve better strength.
2) Plasticizing system: Ester plasticizer is the most commonly used plasticizer for CPE
3) Stable protection system
When CPE is heated or vulcanized (non-peroxide vulcanization system), hydrogen chloride will be released, so a stabilizer with acid absorption effect should be used in the formulation, such as calcium stearate, barium stearate, tribasic lead sulfate or magnesium oxide.
4) CPE vulcanization system: CPE is a saturated rubber, which cannot be effectively vulcanized by common sulfur vulcanization systems.
Precautions for the use of pvc insulated cable
1. The wires should not be damp, heated, corroded or bruised.
2. When the wires have been used for a certain period of time, they should be inspected carefully, and if they are found to be faulty, they should be replaced in time.
3. Do not overload the wires.
4. Frequently check the use of electrical and wiring in the home, and perform maintenance and repairs in time.
5. For the lines of old-fashioned buildings, if they are found to be flooded or wet, especially if the lines are in disrepair and aging, please ask an electrician to repair them immediately.
6. For lines that are easy to be soaked by floods, electricians should be asked to relocate the lines and take elevated and moisture-proof measures.
7. In case of power failure in rainy days, the power supply of pvc insulated wire should be cut off immediately, and an electrician should be asked to check the cause, and special personnel should be sent to take care of it.