DZ20系列塑料外壳式断路器(以下简称断路器),其额定绝缘电压为660V,交流50Hz额定工作电压380(400)V及以下，其额定电流从16A至1250A.一般作为配电用,其中Y、J、G型的额定电流225A及以下和400Y型的断路器亦可作为保护电动机用.在正常情况下,断路器可分别作为线路不频繁转换及电动机的不频繁起动之用. 四级断路器主要用于交流50Hz、额定电压400V及以下，额定电流16A至630A三相四线制的系统中，它能保证用户和电源完全断开，确保安全，从而解决三极断路器的不可克服的中性极电流不为零的弊端．　配电用断路器，在配电网络中用来分配电能，且可作为线路及电源设备的过载，短路和欠电压保护．　保护电动机用断路器在配电网络中用作鼠笼型电动机的起动和运转中分断以及作业电动机的过载．2、型号及含义 附件名称无报警触头分励脱扣器二组辅助触头欠电压脱扣器分励脱扣器二组辅助触头分励脱扣器欠电压脱扣器四组辅助触头二组辅助触头欠电压脱扣器欠电压脱扣器报警触头二组辅助触头报警触头欠电压脱扣器报警触头二组分励脱扣器辅助触头报警触头分励脱扣器欠电压脱扣器报警触头四组辅助触头报警触头二组辅助触头欠电压脱扣器报警触头瞬时脱扣器附件代号200208210220230240250260270218228238248258268278复式脱扣器附件代号3003083103203303403503603703183283383483583683783、过电流脱扣特性表壳架等级额定电流ImmA 约定发热电流IthA短路分断能力级别短路分断能力KA（有效值）断路器额定电流InAIcu/COS Icu/COS 160160C12/0.30-16,20,25,32,40,50,63,80,100,125,160100100Y18/0.3014/0.3016,20,25,32,40,50,63,80,100100100J35/0.2518/0.3016,20,25,32,40,50,63,80,100100250G100/0.2050/0.2516,20,25,32,40,50,63,80,100250225C15/0.30-100,125,160,180,200,225,250225225Y25/0.2519/0.30100,125,160,180,200,225225225J42/0.2525/0.25100,125,160,180,200,225225225G100/0.2050/0.25100,125,160,180,200,225400400C20/0.30-100,125,160,180,200,225,250,315,350,400400400Y30/0.2523/0.25200,225,250,315,350,400400400J42/0.2525/0.25200,225,250,315,350,400400400G100/0.2050/0.25200,225,250,315,350,400630630C20/0.30-400,500,630630630Y30/0.2523/0.25400,500,630630630J50/0.2525/0.25400,500,63012501250Y50/0.2532.5/0.25630,700,800,1000,125012501250J65/0.2032.5/0.25800,1000,1250