The low voltage circuit (even with low voltage on it) shall also be connected with protective earth, thus the dangerousvoltage can be detected.
低电压电路（即使它们是低电压）必须和保护地连接，这样危险电压才能被检测出来。
2
This article analysed the reason of dangerousvoltage merging into from the connection way of ground connection system and equivalent circuit aspects, and put forward a solution.