Industry News

  We all know that the quality of a product is first judged by its appearance. For cables, the appearance refers to the sheath, which must be smooth, rounded, with uniform gloss, concentricity (within specified deviation), and free from mechanical damage, flattening, impurities, bubbles, pitting, obvious granules, bamboo-like deformations, or spiral twists. Beyond these factors, the thickness of the cable sheath is also an indicator of quality. A sheath thickness below the standard requirement is deemed non-compliant, but exceeding the standard is equally unacceptable. For example, for a cable model ZR-KVVP 4*1.5mm², if the average measured sheath thickness is 1.6mm, while the reference standard GB9330-88 specifies a thickness of 1.2mm, it is considered non-compliant for the following reasons:

(1) Reduced Service Life: After installation, cables carry electrical current for extended periods, generating heat. The allowable conductor operating temperature is 70°C, and the long-term use temperature of PVC should not exceed 65°C. In summer, operating temperatures rise, and this heat must dissipate through the outer sheath. An overly thick sheath impedes heat dissipation, adversely affecting the cable's service life. Under heat, PVC undergoes a series of physical and chemical changes, losing its original excellent properties. This leads to a significant decline in insulation performance and may even cause short circuits, disrupting normal equipment operation.

(2) Material Performance Deficiencies: Material performance is not reflected through thickness. According to the GB8815-2002 standard, if certain indicators, such as the oxygen index of flame-retardant PVC materials falling below 30, fail to meet requirements, the material is substandard.

(3) Structural Issues in the Cable: If the conductor, insulation layer, and braiding density are controlled according to standard requirements, and appropriate fillers are selected to ensure roundness, how could the sheath be extruded so thickly? This indicates potential structural problems.

(4) Increased Installation Difficulty: Modern cable installation primarily uses cable trays or conduits. Many companies now demand compact cables with smaller outer diameters to allow gaps during installation for heat dissipation and to protect the outer sheath from damage. An overly thick sheath makes installation challenging for construction teams.

  In summary, cable sheath thickness should be controlled according to standards—thicker is not better. Conversely, producing excessively thick products wastes the company's resources, increases costs, reduces profit margins, and fails to ensure product quality. Therefore, it is essential to adhere to standard thickness requirements, guarantee cable quality, and create high-quality, reasonably priced products that satisfy customers.