5. We find there is the electricity on the case when using your product. May we ask if it is normal and if it can cause body injury?
General speaking, the switch power has a suspension voltage (i.e.: the induced voltage), which causes the phenomenon (i.e.: the case is electrified). Such phenomenon is described and specified by IEC60950-1; for instance the leakage current of the information equipment must be less than 3.5mA; if so it can be solved if connecting it with the ground correctly.