低压开关柜和控制柜 - 第3部分:开关 隔离开关 隔离开关和保险丝组合单元

[中文适用范围]： 本部分IEC 60947标准适用于额定电压不超过1000V交流电或1500V直流电的配电电路和电机电路中使用的开关、隔离器、隔离开关和熔断器组合电器及其专用附件。本文件不适用于属于IEC 60947-2、IEC 60947-41和IEC 60947-5-1范围内的设备。用于光伏（PV）直流应用的开关、隔离器、隔离开关和组合电器的具体要求在附件D中给出。用于铝导体连接的低压开关柜的具体要求在附件E中给出。附件F提供了功率损耗测量的指导。本文件不包括用于爆炸性气体环境的电气设备所需的额外要求。 [外文原描述]： IEC 60947-3:2020 applies to switches, disconnectors, switch-disconnectors and fuse-combination units and their dedicated accessories to be used in distribution circuits and motor circuits of which the rated voltage does not exceed 1 000 V AC or 1 500 V DC. This fourth edition cancels and replaces the third edition published in 2008, Amendment 1:2012 and Amendment 2:2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - addition of critical load current tests for DC switches (see 9.3.9); - addition of requirements for a conditional short-circuit rating for disconnectors, switches, and switch-disconnectors protected by circuit-breakers (see 9.3.7.2); - addition of new categories for high-efficiency motors switching (see Annex A); - addition of new Annex E for connection to aluminium conductors; - addition of new Annex F for power losses measurement. The contents of the corrigendum of October 2021 have been included in this copy.