With the development of China's national economy, urban construction is becoming more and more prosperous, and its wire market for decoration needs to be strong.The following cable are commonly used,such as H07VV-R, pvc copper wire,electric copper wire.
By entering the market to investigate, consumers often find such problems when comparing the same specifications in the market. Why are the outer diameters of the conductors of different manufacturers' wires and wires inconsistent, for example, the conductors for 6mm2 wire are used as an example, and some The outer diameter of the manufacturer's conductor is 2.76 mm, and the outer diameter of the manufacturer's conductor is 2.90mm or even larger. This creates an illusion for the consumer. The larger the outer diameter of the conductor, the better the wire is. Actually, for this situation, the following Three aspects talk about this issue:
The national standard strictly stipulates the outer diameter of the conductor and the performance index of the direct current resistance, and clearly stipulates that the conductor of the 6mm2 cloth wire shall not exceed the required value.
In the 1980s, the raw material copper smelting production process was not high, and there were many impurities in the copper rod, which caused the conductor resistance to be too large. Therefore, in order to ensure the DC resistance of the cloth wire, the national standard strictly required the outer diameter of the wire conductor. With the continuous development of copper smelting level and the improvement of conductor processing technology, the content of impurities in copper materials is getting smaller and smaller. At present, in the industry, each factory guarantees that the DC resistance of the conductor meets the requirements, and the outer diameter of the conductor is also produced. Correspondingly, the consumption of copper is also reduced accordingly. This is also the reason why only the maximum outer diameter of the conductor is specified in the national standard, and the specific value of the conductor is not clearly specified.
3, According to the conductor DC resistance formula:
R is the DC resistance of the conductor;
ρ is the conductor resistivity at an ambient temperature of 20°
L is the conductor unit length
S is the conductor cross-sectional area
According to the formula, in order to ensure that the current carrying capacity of the wire meets the requirements, the DC resistance of the conductor must meet the standard requirements, and the DC resistance is affected by ρ and S according to the formula, S is related to the diameter of the conductor, and the purity of ρ and copper. It is related that when the DC resistance of the conductor is constant, when the outer diameter of the conductor is large, ρ increases, and the purity of the copper material decreases. If the outer diameter of the conductor is small, ρ decreases, and the purity of the copper material increases.
According to the analysis of the above three aspects, when the consumer chooses the wire and wire products, the outer diameter of the wire conductor can not be judged as the only criterion to judge the product, that is, when the wire specification is selected, the outer diameter of the conductor is more It is not good, but the quality of the product should be judged based on the DC resistance of the conductor and the mechanical properties.