RT18（俗称 HG30）为有填料封闭管式圆筒形帽熔断器，标准 TH35mm 导轨模数化安装，由熔断器底座 + 圆柱形熔芯两部分组成，主要用于交流 50Hz 配电回路，做线路过载、短路全范围保护（使用类别 gG），广泛配套直流屏、控制柜、照明箱、光伏汇流箱、机床控制回路。

RT18 (commonly known as HG30) is a filled enclosed tubular cylindrical cartridge fuse. It features standard TH35 mm guide rail modular mounting and consists of two components: the fuse base and the cylindrical fuse element. This fuse is primarily designed for AC 50 Hz distribution circuits to provide comprehensive protection against line overloads and short circuits (Category of Use: gG), and is widely used in DC power panels, control cabinets, lighting boxes, photovoltaic combiner boxes, and machine tool control circuits.