Nearly all metals will oxidize and deteriorate over time. Plating copper conductors with a non-reactive metal to environmental factors is an excellent means of increasing the longevity of conductors. It is therefore essential that the plating method is such that when the source is drawn though a die, the plating material remains uniform and continuous.
The Plating Continuity test is a quality and product control test. Wire and cable conductors are typically not forged as small strands; they are produced as long bars, plated, then drawn through dies to reduce their size. As the conductor is pulled through the die, the diameter of the conductor is progressively reduced until through multiple dies in until the proper gauge is achieved. This process reduces the diameter of the conductor and the thickness of its plating. This test chemically attacks the conductor, opportunistically searching along the length of the plating for copper to consume.