How can an electric FTU pass an ESD electrostatic discharge test?

For an FTU to pass ESD electrostatic discharge testing, a low-impedance discharge path must be established. Contact discharge points (metal casing) must ensure continuous conductivity, using beryllium copper springs at seams with a contact resistance of less than 0.1Ω. Air discharge points (gaps, buttons) must be reinforced with a metal shielding mesh with a mesh size of less than 5mm. Interface circuit protection: ESDSM712 is used for the communication port, and SMBJ24CA for the power port. PCB design: Sensitive circuits are kept away from discharge points, with a spacing greater than 10mm. Grounding system: The chassis is grounded through a low-impedance path (25mm² copper strip). With this design, the FTU can pass IEC 61000-4-2 Level 4 testing (8kV contact discharge, 15kV air discharge), and functions normally after testing.