IEC 61557-4:20 19 RLV包含官方IEC国际标准及其红线版本。Redline版本不是官方文档，它只有英文版本，为您提供了一种快速简单的方法来比较IEC官方标准与其以前版本之间的所有变化。 IEC 61557-4:20 19规定了适用于测量接地导体、保护接地导体和等电位连接导体（包括其连接和端子）电阻的设备的要求，并标明了测量值或限值。IEC 61557-4:20 19取消并取代了2007年发布的第二版。本版构成技术修订版。与上一版相比，此版本包括以下重大技术变更:a)补充条款4中的测量类别； b)校正运行不确定性方程； c)补充DC测量的要求； d)结构与整个IEC 61557系列的结构对齐。

IEC 61557-4:2019 RLV contains both the official IEC International Standard and its Redline version. The Redline version is not an official document, it is available in English only and provides you with a quick and easy way to compare all the changes between the official IEC Standard and its previous edition.

IEC 61557-4:2019 specifies the requirements applicable to equipment for measuring the resistance of earth conductors, protective earth conductors and conductors for equipotential bonding, including their connections and terminals, with an indication of the measured value or an indication of the limits. IEC 61557-4:2019 cancels and replaces the second edition published in 2007. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) complement to the measurement category in Clause 4;
b) correction of the equation for operating uncertainty;
c) complement to the requirements for measuring with DC;
d) alignment of the structure with that of the whole IEC 61557 series.