How to distinguish between poor quality cable?

First, the harms of shoddy wires

Cable is related to the safety of life and property of millions of households and almost all industries can run a special commodity, the use of a wide range, especially in the temporary use of lines and home decoration with a very large indoor use of the line, if the use of fake and shoddy Of the wire and cable, light may cause short-circuit, electric shock, heavy may lead to fire, resulting in casualties. By the end of 2009 the Yunnan Provincial Trade and Industry Bureau of the sampling results show that the flow of the province nearly 60% of the wire and cable failed, the market nearly half of the wire and cable parts of the heart - the existence of the phenomenon of cutting corners. Yunnan fire department's rough statistics show that in recent years, more than four percent of the fire caused by electrical failure, copper core "shrink" of the black core wire and cable is one of the main reasons.

Second, the characteristics of shoddy wires

1, cable length is not enough

Unscrupulous manufacturers of the main means is to make the article on the length of wire and cable, wire and cable actual length is less than the nominal length, and pricing charges in accordance with the nominal length of the implementation. The most typical is the volume of packaging wire cloth, in the national standard provides 100 meters per volume, measurement error is not greater than 0.5%, which is the length of each coil is 100 ± 0.5 m, and many manufacturers are blatant in the qualified card On the marked 100 ± 20 meters, the actual length of only 80 meters, if its price equivalent to per meter, it is not cheap. Such cheats are easier to identify, first, to see qualified card; second sampling length, because the cloth is relatively soft wire, easy to measure.

2, the resistance value does not meet national standards

The resistance value of the wire at the same current its temperature may be too high, thus accelerating the aging of the outer insulation layer, resulting in short-circuit fire; and because of excessive resistance, but also greatly increase the transmission process energy consumption and increase electricity costs.

3, poor raw materials

The first trick is to play the copper conductor of the idea, copper conductor accounted for 80% of the cost of wires, poor manufacturers is to reduce the quality of copper. The use of much lower prices of copper impurities, copper recovery, and even indigenous copper, copper content is very unstable, leading to copper conductor resistivity. The second is to reduce the amount of copper. Reduce the actual cross-sectional area of the copper core, the direct result of these two practices is the use of wires in the process of overheating, damage to the plastic insulation, resulting in short-circuit caused by fire.

The second trick is to use plastic in the insulating layer on the moving bad eye, and copper as lower quality, per ton of renewable insulation material and qualified PVC plastic powder price difference of nearly 2,000 yuan, but the regeneration of insulating material with high impurity content, low mechanical strength , Anti-aging properties and electrical insulation performance decline, this approach will lead directly to the phenomenon of wire leakage prone.

Third, the identification of shoddy wires

1, see the label. The content of the certification of the electric wire produced by the regular manufacturer shall include: 3C certification mark, certification number, model specification, execution standard, rated voltage, wire length, date of manufacture, producer, inspector, factory name, factory address, fixed telephone, Wait. The counterfeit labels are often unclear print or printed content is incomplete.

2, look at the surface. The plastic sheath of the regular wire is soft and smooth, and the color is even. In its surface, should also be printed on the product certification on the number of content, such as: 3C certification mark, certification number, model, rated voltage, the implementation of standards, such as factory name. At the same time, the writing must be clear and difficult to erase.

3, try bending. It is desirable to use a hand repeatedly bent wire, soft to the touch, good fatigue strength, plastic or rubber feel flexible and no crack on the wire insulator is superior products. Pseudo-wire insulation looks very thick, in fact, mostly made of recycled plastic, as long as a little hard extrusion, extrusion will become white-like, bending 4 to 6 times there is disconnection;

4, tear insulation. High-quality insulation materials have a certain degree of mechanical strength and flexibility, easy to tear open. And low-grade wires can be torn off or pinch down a piece;

5, look at the burning. According to the provisions of the wire insulation layer has a certain flame retardant. Peel off a layer of insulation, with a lighter to ignite, to leave the fire can continue to spontaneous combustion is a bad line.

6, test thickness. Intercept an insulating layer to see whether the insulating layer of the visible section of the pores, the core is located in the middle of the insulating layer. Is not centered because the process is not high caused by partial eccentric phenomenon, the use of stomatal insulation material failed. Eccentric serious The most vulnerable in the thinner side of the leakage, there is impact on the compressive strength of the pores.

7, see the copper wire. The color of high-quality copper wire is bright reddish, and inferior copper wire is violet black, partial black, partial yellow or partial white, hardness, impurities, mechanical strength is poor, poor toughness, , And the wire is often broken phenomenon. For multi-strand of the soft wire, touch the top with the palm of the wire, feeling should be smooth, and no tingling, feel more soft. Otherwise it is poor quality wire.