IEC 61386-21:20 21作为IEC 61386-21:20 21 RLV提供，其中包含国际标准及其红线版本，显示了与上一版本相比技术内容的所有变化。 IEC 61386-21:20 21规定了刚性导管系统的要求。本文件应与IEC 61386-1:20 08和IEC 61386？1:2008/AMD1:2017。第二版取消并取代了2002年出版的第一版。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: -增加了第7.1.103款，要求制造商声明导管是否可弯曲； -增加了附件AA，为使用不断增加的武力提供指导。

IEC 61386-21:2021 is available as IEC 61386-21:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 61386-21:2021 specifies the requirements for rigid conduit systems. This document is to be used in conjunction with IEC 61386-1:2008 and IEC 61386？1:2008/AMD1:2017. This second edition cancels and replaces the first edition published in 2002. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- Subclause 7.1.103 has been added requiring the manufacturer to declare whether the conduit is bendable;
- Annex AA has been added to provide guidance on the application of a constantly increasing force.