This standard is part of a series of test methods for bare wires, specifically specifying the detailed test method for examining the continuity of surface coatings (such as tin, silver, nickel, etc.) on copper conductors of wires and cables using the sodium polysulfide method. The standard elaborates on the required equipment, sample preparation procedures, specific measurement steps, and criteria for evaluating test results. This method is equivalent to the ammonium persulfate method and should be used in conjunction with the general provisions of the bare wire test methods in practical applications. In actual testing, the primary instruments involved are conventional laboratory glassware, such as graduated cylinders used for containing and preparing sodium polysulfide test solutions. This standard is mainly intended to guide production and quality inspection personnel in the wire and cable industry to ensure that the quality of metal coatings on products meets relevant requirements.