Based on the above two analysis, it is not difficult to see that the quality of the product is good or bad, and its first feature is reflected in the appearance quality of the product. Regardless of the product or the semi-finished product, the appearance must be paid attention to in the production. The quality is strictly controlled and inspected. The sheath is the appearance of the cable. Its appearance requirements are smooth and round, uniform gloss, not eccentric (not exceeding the specified deviation), no mechanical damage, flattening, no visible debris, air bubbles, sand holes, obvious particles, and bamboo Nodal shape, twist shape, etc. In addition to meeting the above quality requirements, the thickness of the sheath also has a certain impact on the quality of the cable.

      It is well known that the function of the  solar extension cable sheath is to protect the insulated core of the MC4 solar extension cable from damage under the action of external force and play a protective role. If the thinnest point of the  solar extension cable sheath fails to meet the requirements, the MC4 solar extension cable sheath will be damaged before reaching the normal maximum external destructive force. If the thickness of the sheath in the production of the MC4 solar extension cable is lower than the standard requirement, it is unqualified, and the thickness exceeds the standard requirement is also unqualified. For example: the MC4 solar extension cable model is DLD-KYJV22 3*1.5mm2, and the measured thickness of the sheath has an average thickness of 1.7mm. This model should refer to the GB9330-88 standard and the thickness should be 1.2mm.