1.1 本规范涵盖裸轮21 % 导电性铜包钢线，用于示踪线中的中心导体，也称为定位线。 1.2 铜包钢线的两个等级如下: 1.2.1 21 EHS: 标称21 % 导电性超高强度 1.2.2 21EHS-A: 标称21 % 电导率超高强度退火 1.3 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值； 因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 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。 ====意义和用途====== 14.1 扭转试验- 本试验旨在检测与表面相关的问题，如外壳中的剥落或开裂，以及与伸长率相关的导线芯完整性。规定要求下的故障可能导致绝缘故障，从而导致水分和其他因素影响导线性能。 14.2 反向扭转- 该测试旨在检测铜和芯钢的粘接问题，这些问题可能导致腐蚀，并最终导致导线信号故障。

1.1 This specification covers bare round 21 % conductivity copper-clad steel wire for the center conductor in tracer wire, also known as locating wire. 1.2 Two grades of copper-clad steel wire are covered as follows: 1.2.1 21EHS: Nominal 21 % Conductivity Extra High Strength 1.2.2 21EHS-A: Nominal 21 % Conductivity Extra High Strength-Annealed 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 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. ====== Significance And Use ====== 14.1 Twist Test— This test is designed to detect surface related issues such as flaking or cracking in the shell as well as core integrity of the wire related to elongation. Failures under the specified requirements could lead to insulation failures allowing moisture and other factors to affect wire performance. 14.2 Reverse Torsion— This test is designed to detect copper and core steel bonding issues which could lead to corrosion and eventual signal failure through the wire.