YD9952 is a necessary instrument for electrical safety inspection and maintenance of new energy vehicles, which integrates insulation resistance, grounding continuity testing, and AC/DC voltage testing. This meter adopts a lightweight and portable design, and can be used for multiple purposes. It can test the insulation resistance between the electrical parts of the tram, the potential balance characteristics between the connected components of the tram (grounding connectivity testing), the battery and circuit board, and the charging voltage (AC/DC voltage testing), providing great convenience for the maintenance personnel of new energy vehicles.