How to choose the cable?

The non-standard cable industry is not an alarmist word. According to sampling results from related departments in the past two years, nearly 60% of the wires and cables in the circulation area are unqualified, and the heart of wire and cable, which is nearly 50% on the market, is the copper core. There is a phenomenon of cutting corners.

The inferior cable has the following characteristics:

1, the cable length is not enough

The main method commonly used by unscrupulous manufacturers is to make articles on the length of wire and cable. The actual length of wire and cable is less than the nominal length, and the charge for pricing is performed according to the nominal length.

The most typical is the rolled packaged wire. In the national standard, it stipulates that each roll is 100 meters and the measurement error is not more than 0.5%. That is, the length of each roll is 100±0.5 meters, and many manufacturers are blatant in the qualified card. The mark is 100±20 meters. The actual length is only about 80 meters. If its price is reduced to every meter, it is not cheap.

Such deception is easier to identify. One is to look at the qualified card; the other is the length of the sample, because the cloth is relatively soft and easy to measure.

2. The resistance value does not meet the national standard

Wires with an electrical resistance exceeding the specified value may have too high a temperature at the same current, thereby accelerating the aging of the outer insulation layer and causing a short circuit to cause a fire; and because the electrical resistance exceeds the standard, the power consumption during the transmission process will be greatly increased, and the cost of electricity will be increased.

3, poor material quality

The first trick was to use copper conductors. Copper conductors accounted for 80% of the cost of wires. The bad manufacturers first reduced the quality of copper. The use of much lower-cost impurity copper, recycled copper, and even indigenous copper smelting made the copper content extremely unstable, resulting in a significant increase in the resistivity of copper conductors.

The second is to reduce the amount of copper. To reduce the actual cross-sectional area of ​​the copper core, a direct consequence of these two practices is that the wire is overheated during use, damages the insulating layer plastic, causing a short circuit and causing a fire.

The second measure is to break the heart on the plastic used in the insulation layer and degrade it like copper. The difference between the price per ton of recycled insulation material and qualified PVC plastic powder is nearly 2,000 yuan, but the content of recycled insulation material is high and the mechanical strength is low. , Anti-aging performance and electrical insulation performance decline, this practice will lead directly to lead to electrical leakage.

The cable quality should be identified as follows:

1, see the label.

The contents of the certificate of conformity of the regular manufacturers shall include: 3C certification mark, certification number, model specification, implementation standard, rated voltage, wire length, production date, producer, inspector, factory name, site, fixed telephone, security label Wait. However, the labels of fake/risk products are often unclear or incompletely printed.

2, look at the surface.

The plastic sheathing of the regular wires is soft and smooth, with uniform color. On its surface, it should also be printed with several items on the product certification, such as: 3C certification mark, certification number, model, rated voltage, implementation standards, and factory name. At the same time, the writing must be clear and difficult to erase.

3, try to bend.

It is advisable that a wire head be repeatedly bent by hand, and that any product that has soft touch, good anti-fatigue strength, high elasticity of plastic or rubber feel, and no crack on the wire insulator is a superior product. Insufficient wire insulation seems to be very thick, in fact, most of them are made of recycled plastic, as long as a little squeeze, the extrusion will be white, bending 4 to 6 times there will be broken phenomenon.

4, tear insulation.

High-quality insulating materials have a certain degree of mechanical strength and flexibility and can't be easily torn. And poor quality wires can be torn off or smashed down by hand.

5, see the burning.

According to the provisions of the insulation of the wire has a certain degree of flame retardant. A section of insulation is peeled off and ignited with a lighter. It is a poor quality line that can continue to ignite spontaneously after leaving the open flame.

6, inspection thickness.

A section of insulating layer is cut to see if the cross-section of the insulating layer is visible to the naked eye, and whether the core is located in the middle of the insulating layer. Non-centered is due to the fact that the process is not high and the phenomenon of eccentricity has porosity, which indicates that the insulation material used is not qualified. Eccentricity is most likely to leak electricity on the thinner side, and porosity also affects the compressive strength.

7, see the copper wire.

The color of the high-quality copper wire is bright reddish, and the inferior copper wire is purple black, black, yellow or white, high hardness, many impurities, poor mechanical strength, poor toughness, and will be broken if it is a little hard. , And there are often broken wires inside the wire. For multiple strands of soft wires, touch the tip of the copper wire with your palm and the feeling should be smooth, without tingling, and feel softer. Otherwise it is a bad wire.

8, a fine inner diameter and outer diameter, see the weight of Pison.

It means that if the above six methods cannot be determined, the outer diameter and the core diameter of the insulated wire can also be measured. The allowable error is ±10%. If the measured value exceeds the allowable error, it is basically an inferior insulated wire.

In order to facilitate everyone's memory, Xiao Bian condensed the omnipotent Raiders into the following recipes. We must keep in mind:

Take a closer look at the label printing samples. The address of the handwriting is unknown.

Insulation is broken by hand and the quality of the word drop is poor.

Then use a fingernail to remove the skin line.

Repeatedly bend the insulated wire and break it three to four times.

Use fire to ignite the wire and leave the open flame for self-ignition.

The core is usually made of aluminum and copper, and the color is dark and light.

Measure the inner diameter and outer diameter, and weigh it again.