The oxidation blackening of the conductor copper wire of the wire is caused by a variety of reasons, mainly including the following four aspects:

1. The reason for covering PVC is that PVC is exposed and the end of the line is not sealed;

Second, the quality of copper wire itself, too many impurities;

Storage problems, warehouse moisture, etc.

Iv. Production process.Not strictly in accordance with the standard process production or production process water.