How to identify the inferior wire and cable

- Apr 08, 2018 -

Wire and cable is the main carrier of electric power transmission. Its application scope is very extensive, especially in urban network, rural network transformation and new projects. To this end,

Generally speaking, when the insulation wire is sold or used on the market, it is mainly to see the labels, labels and 3C marks on its products or packages. However, when the users actually buy it, many insulated wires, even if the quality has problems, have 3C marks on their products or packages, so it is difficult to distinguish the true and false for a moment. In this case, you can't believe it easily. According to the introduction, the inferior wire has a great harm. The first is the low security performance. The insulation layer of many wires is not made of regular insulating plastic, but is made of recycled plastic. The insulating layer can be peeled off gently. It is very easy to cause insulation layer to be electric current and leakage, causing great threat to the safety of the user's life. Next is the thickness of the conductor, which determines the load of the wire to the current. The larger the current is, the greater the thickness of the conductive core will be. It is found in inspection that the actual section size of many wires is much smaller than the size indicated by them. For example, many wires, known as the core section, are 4 square millimeters. The measurement is only 2.5 square millimeters, and some even have 1.5 square millimeters. When consumers use this product, they will cause excessive heat and cause electrical fire hazards.

The following techniques are used to identify inferior insulated wires:

One, ordinary wire

(1) look at the printed words on labels and insulating skins. If there are any wrongly written or printed characters, they should be noticed.

(two) rubbing the insulated outer skin with the finger, some inferior insulated wire skin is easy to fade, especially the red line will appear this kind of problem, after rubbing the finger, the color of the line skin or the print on the online skin is usually wiped out of the inferior line.

(three) with nail fingernails and pinching insulation, it is usually inferior line that can be rowed down and pinched down.

(four) repeated bending of insulated wires, poor quality insulation materials generally poor material, bending 3~4 times, the insulation will be broken.

(five) ignite the insulation layer, and the spontaneous combustion is inferior line after leaving the open fire.

(six) look at the color of the core, the color of the bad line is gray and no metallic luster.

(seven) the length of the package is usually 100 meters per lash or circle. The national allowable error is 0.5%, and the length of the inferior wire is only 95 meters, or even less; some are misled on the package by "code".

(eight) if the above 7 methods can not be determined, it can also measure the diameter of the insulated wire and the diameter of the wire core. The measured value is quite different. It is basically the inferior insulated wire. (notice: there are many bad manufacturers at present, the conductor is not cross section, and the insulation or sheath thickness is increased to reach the whole wire outer diameter for deception use. Household).

Two, no halogen and low smoke environmental protection wire

At present, the problem of domestic technology or raw materials is only using irradiation technology to ensure that the insulation of halogen - free and low - smoke flame retardant wires are not damaged by high temperature and humidity, and non - irradiated crosslinked and low - smoke and low smoke flame-retardant wires, even if they have been tested in warm water, there are also problems in the design engineering application. In 2005, the non irradiated, halogen-free and low smoke flame retardant wire used by a civil engineering in Nanjing was laid out in wet environment, and the insulation strength was not enough for many lines. There were many design institutes in China, such as the Olympic project of Beijing Architecture Research Institute, the underground shopping mall in Beijing West passenger station and the Guangdong Science Center. No halogen and low smoke flame-retardant cable can be used in engineering.  Because the non halogen-free and low smoke flame retardant wires with non irradiated crosslinking are especially easy to absorb water (a lot of AL (OH) 3 or Mg (OH) 2) are used for the thermoplastic non halogen-free and low smoke materials. According to the experiment of the national wire and cable testing center, the insulation resistance of the non halogen and low smoke flame retardant wires with non irradiated crosslinking has been reduced by 100~1000 times after the temperature and water test.

Therefore, identifying this kind of wire is very simple, just to see whether the production enterprise has the irradiation cross-linked cable production line.

Three. Fire resistant wire

Identify the inferior quality wires and identify the mica tape on the basis of common wires.

(1) generally use 2 layers of mica tape to wrap around, and the overlap rate is around 50%.

(two) the quality of mica tape is also critical, gently rub, such as powder, that is bad.

(three) using flame to produce mica, such as flame passing through mica tape, is inferior fire-resistant wire.

Small electrical knowledge

Power P=I2 * R: I -- current R -- conductor resistance.

And R is inversely proportional to the cross section S of the conductor, that is to say, the subtraction of the inferior wire on the conductor cross section will not only cause the wire conductor to overheat and the insulation aging, thus causing the danger of the electrical fire and the loss of the electric energy. For example, the cross section is only 90%, so the power consumption of the conductor is 10% more than that of the standard section.

In short, such as the use of inferior wire, it will produce: 1, insulation easily breakdown or premature aging, generation of electricity leakage; 2, wire fever severe; 3, electricity consumption large; 4, easily triggered fire, causing human and livestock casualties and so on.

As the saying goes, "one cent, one share", we hope that consumers will be cautious when choosing purchasing wires. In fact, you are not only buying products, but you are also buying a kind of safety and insurance.


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