How does the equipotential bonding of the intelligent low-voltage monitoring unit suppress common mode?

Equipotential bonding suppresses common-mode voltage using a mesh system. All metal components are interconnected via 4mm² copper wire with a connection resistance of less than 0.1Ω. The cable shielding is grounded at both ends. On the PCB, analog ground, digital ground, and power ground are individually connected to the equipotential reference point via 0Ω resistors. A CMZ3225A-501T common-mode inductor is installed at the power input, along with a CY-Y1-222K Y capacitor. Through equipotential bonding, the common-mode voltage within the system is less than 2V, and the common-mode rejection ratio is greater than 50dB, meeting the IEC 61000-4-6 conducted immunity 10V test requirements.