Method for identifying building security and inferior cables

The good and bad cable identification, the real test requires specialized equipment and instruments. In practice, preliminary identification can be performed according to the following methods:

1. PVC jacket: The surface can see that there is a regular “unevenness” on the inside of the crimping net, which means that the processing technology is good, no relative sliding will occur, and the cables are good; the appearance is smooth, and the compact net is not visible. The degree of unevenness, there is a sense of looseness with the hand jacket, is a poor cable.

2, check the shielding layer network: whether the number is enough, copper wire mesh, check the weldability, tinned copper wire to see if it is inside the copper wire, aluminum-magnesium alloy wire hardness is significantly greater than the copper wire; braiding network is sparse, Non-uniform distribution, and the insulation layer is not tight, such as poor cable.

3, check the core: diameter SYV cable is 0.78 to 0.8mm, SYWV cable is 1.0mm; recently appeared a SYV75-5 core diameter is 1.0mm cable, the characteristic impedance of this cable, certainly not 75 ohms, Not applied to 75 ohm transmission systems.

4. Check the adhesion between the core wire and the insulating layer: Cut the insulation layer obliquely, pull the core wire in the peeling direction, and see if the core wire and the insulation layer have any adhesion process material; good cable has a large adhesive force, poor cable No adhesion. Longitudinal tensile test: Take one meter cable, peel off the core layer, insulation layer, shielding layer, and outer sheath layer by layer, each leaving 10 cm long. The method is: Two hands hold the adjacent two layers of the cable and pull in the opposite direction; the cable is generally unable to pull the power, so the cable can be easily pulled out without any effort.

The above points of identification of security cables mainly include visual inspection and appearance identification. For example, more in-depth identification requires certain tools or equipment detection. Transmission performance testing, oscilloscope measurement, and other detection methods can be used for identification.

Today, KeXun Cables brings you the means to identify the building security and inferior cables. If you think that there is any knowledge about the wire and cable, you can visit KeXun Cable.