Induction electricity
The electricity carried by the outside of the conductive equipment, the general control system must have a switching power supply and a filter, and they all have Y capacitors, that is, the 220V LN-to-ground (chassis) capacitor. If your circuit system is not grounded, then the housing is There will be an AC voltage of 110V.
Protection
1. The external power supply must be grounded (the third pin on the socket must be grounded).
2. Standard connection L is connected to live wire, and N is connected to neutral wire. (Many domestic electricians are random and irrelevant).
3. The best way is to hit a copper rod (1~1.5 meters long) in the ground soil, and then lead a ground wire to connect with the machine shell.