Precautions
1、 Observe the appearance of the wire. The insulation (sheath) layer of qualified products is soft, tough and flexible, and the surface layer is tight, smooth and free of roughness. If the plastic wrapping the wire is easy to peel off, there is a problem of insufficient plastic strength.
2、 It depends on the cross-section of the wire. The surface of copper core or aluminum core of qualified products should have metallic luster. Copper with black surface or aluminum with white surface indicates that it has been oxidized.
3、 Pay attention to check the quality certificate when purchasing wires. If the quality of the wire is qualified, the wire quality should also be tested, and there will be no big problem.
