美国UL 674新老标准的主要技术差异及新增内容介绍

Introduction on Main Differences of Forth-and Third-version of UL 674 and Content Added

对UL 674标准第四版与第三版的主要技术差异进行了分析对比,并对新标准中增加的内容进行了简单的介绍。

In this article, the main difference between forth version and third version of UL674 is compared and analyzed, furthermore, the new eontent added in the forth version of this standard is introduced.