该包包含IEC 61439-4:20 23 EXV和IEC 61439-4:20 23 RLV。 IEC 61439-4:20 23定义了ACS的具体要求如下: -额定电压在交流电情况下不超过1 000 V或在直流电情况下不超过1 500 V的组件； -ACS中包含的变压器的标称初级电压和标称次级电压在上述限值内的组件； -拟在室内和室外建筑工地使用的组件，即公众一般无法进入的临时工作场所，以及进行建筑物建造、安装、修理、改动或拆除财产（建筑物）或土木工程（公共工程）或挖掘或任何其他类似作业的地方； -带有外壳的可运输（半固定）或移动组件。IEC 61439-4的第二版取消并取代了2012年发布的第一版。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: a)在结构和技术内容方面符合IEC 61439-1:20 20（如适用）。

This pack contains IEC 61439-4:2023 EXV and IEC 61439-4:2023 RLV.

IEC 61439-4:2023 defines the specific requirements of ACS as follows:
- assemblies for which the rated voltage does not exceed 1 000 V in case of AC or 1 500 V in case of DC;
- assemblies where the nominal primary voltage and the nominal secondary voltage of transformers incorporated in ACS are within the limits specified above;
- assemblies intended for use on construction sites, both indoors and outdoors, i.e. temporary places of work to which the public do not generally have access and where building construction, installation, repairs, alteration or demolition of property (buildings) or civil engineering (public works) or excavation or any other similar operations are carried out;
- transportable (semi-fixed) or mobile ASSEMBLIES with enclosure.
This second edition of IEC 61439-4 cancels and replaces the first edition published in 2012. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) alignment with IEC 61439-1:2020 regarding the structure and technical content, as applicable.