IEC 61858-1:20 14列出了对已建立的电绝缘系统（EIS）的热分类进行修改的鉴定所需的测试程序。本标准适用于线绕绕组电工器件中使用的EIS。测试程序具有可比性，因为将候选EIS的性能与参考EIS的性能进行比较，参考EIS具有符合IEC 60505的经过验证的服务经验，或者已经通过IEC 61857系列中给出的程序之一进行了评估。IEC 61858-1的第一版取消并取代了2008年发布的IEC 61858的第三版。它构成了技术和编辑修订。与上一版相比，此版本包括以下重大技术变更: a)该部分专门用于线绕绕组EIS； b)新的数字和图表支持内容。

IEC 61858-1:2014 lists the required test procedures for qualification of modifications of an established electrical insulation system (EIS) with respect to its thermal classification. This standard is applicable to EIS used in wire-wound winding electrotechnical devices. The test procedures are comparative in that the performance of a candidate EIS is compared to that of a reference EIS, which has proven service experience in accordance with IEC 60505 or has been evaluated by one of the procedures given in the IEC 61857 series. This first edition of IEC 61858-1 cancels and replaces the third edition of IEC 61858, published in 2008. It constitutes a technical and editorial revision. This edition includes the following significant technical changes with respect to the previous edition:
a) this part is specifically for wire-wound winding EIS;
b) new figures and charts support the contents.