【国外标准】 Standard Specification for Track-Resistant Thermoplastic High-Density Polyethylene Insulation for Wire and Cable, 75 °C Operation

This specification covers track-resistant black thermoplastic high-density polyethylene insulation for conducting wires and cables operating continuously at a specified conductor temperature. The insulation is suitable for use for power transmission in overhead spaced-line service that is exposed to sunlight and other atmospheric environments. The prescribed tests cannot be performed unless the insulation is formed around a conductor, but these are done solely to determine the insulation properties and not to test the conductor or completed cable. Each test sample should be subjected to an ac or dc voltage withstand test at voltages that are based on the nominal thickness of the insulation and should comply with the required values for aging, heat distortion, cold blend, U-bend discharge, track resistance, tensile strength, elongation at rupture, environmental cracking, and surface resistivity.1.1 This specification covers track-resistant thermoplastic high-density polyethylene insulation. Before application to the conductor, the insulation shall comply with the requirements of Specification D1248, Type III, Class C or D, Category 5, Grade E10, J4, or J5. The requirements of Specification D1248 shall not apply to the insulation removed from the conductor.1.2 This type of insulation is considered suitable for use on wire or cable that will be used for continuous operation at conductor temperatures up to 75 °C.1.3 This insulation is suitable for use on wire or in cable used for power transmission in overhead spaced-line service, installed at temperatures above −25 °C and exposed to sunlight and other atmospheric environments between −55 and +75 °C.1.4 In many instances, the insulation cannot be tested unless it has been formed around a conductor. Therefore, tests done on insulated wire in this standard are solely to determine the relevant property of the insulation and not to test the conductor or completed cable.1.5 Whenever two sets of values are presented, in different units, the values in the first set are to be regarded as standard. The values given in parentheses are mathematical conversions that are provided for information only and are not considered standard.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.