How to ensure continuity of grounding for the PAC (Power Control Controller) chassis?

The continuity of grounding in the PAC (Power Acoustic Control Unit) chassis is crucial for shielding effectiveness and safety. Firstly, low-impedance connections are achieved between chassis components (e.g., top cover, bottom cover, front panel) using EMI conductive pads or metal springs. The surfaces at these connections must be cleaned and the insulating coating removed to ensure a contact resistance of less than 10mΩ. Secondly, the chassis is connected to the system protective ground via braided copper tape or grounding bolts using the shortest path, with a grounding wire cross-sectional area of not less than 2.5mm².

For removable panels, multi-point connections (e.g., hinges, spring contacts) are used to ensure high-frequency continuity. The shielding ground of the internal PCB should be connected to the chassis via multiple screw holes with a screw spacing less than λ/20 (e.g., less than 15mm at 1GHz). Testing and verification employ a four-point probe method to measure the connection resistance and a network analyzer to measure the transfer impedance. After optimization, the chassis achieves a shielding effectiveness greater than 40dB in the 10kHz-1GHz frequency band, meeting the requirements of the IEC61000-5-2 grounding and connection guidelines.