试解读PEN线分开时接母排的先后次序

Unscrambling the Precedence for Busbar Connection at Separate PEN Conductor

国内先前的做法,美国现行的做法,均为先接N线母排。国际电工委员会IEC标准从人身安全角度考虑,PEN线分开时,应先接PE线母排;但对变电所之类大电流场所,则应让电流顺畅地流回电源,且连接板导电不良是小概率事件,故应先接N母排。

The previous approach in China, the present approach in USA, are both first connecting the N conductor busbar. The conclusion of IEC （International Electrotechnical Commission） codes is that： considering from the personal safety, when the PEN conductor is separate, the busbar of PE conductor should be connected firstly; but for the high current places such as substation, the current should be made to flow smoothly back to the power supply; in addition, the poor conduction of the connecting board is of small probability event, therefore, N conductor busbar should be firstly connected.