1.1 本规范涵盖耐轨道热塑性高密度聚乙烯绝缘。在应用于导线之前，绝缘应符合规范的要求 D1248 ，III型，C或D级，5类，E10、J4或J5级。规范要求 D1248 不适用于从导线上拆下的绝缘层。 1.2 这种绝缘被认为适合用于导线温度高达75°C的连续运行的电线或电缆。 1.3 该绝缘层适用于架空间隔线路服务中用于电力传输的电线或电缆，安装温度高于−25°C，暴露在阳光和其他大气环境中−55和+75°C。 1.4 在许多情况下，除非绝缘层在导体周围形成，否则无法对其进行测试。因此，本标准中对绝缘导线进行的测试仅用于确定绝缘的相关特性，而不是测试导线或完整电缆。 1.5 每当以不同单位呈现两组值时，第一组中的值应视为标准值。括号中给出的值是数学转换，仅供参考，不被视为标准值。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。

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.