What EMC problems can be caused by poor grounding of the edge computing box casing?

Poor grounding of the edge computing box casing is equivalent to a floating antenna, leading to various EMC problems. Firstly, ESD (electrostatic discharge) has no discharge path, directly penetrating the air to the internal circuitry and breaking down ESD diodes such as ESD5V0D8B. Secondly, EFT (electro-force transient) pulses and common-mode currents are coupled into the motherboard through distributed capacitance, causing resets. Thirdly, surge energy cannot be transferred to ground, causing varistors like the 14D391K or TVS 5.0SMDJ33CA to burn out. Fourthly, radiated emissions exceed limits, with the cable acting as an antenna. Fifthly, radiated immunity decreases, and sensitive devices malfunction under strong fields. Solutions include ensuring the casing is connected to the grounding busbar with a low-resistance copper strip (resistance <0.1Ω), adding two Y-capacitors connected to PE at the power input port, and grounding the I/O cable shielding layer 360°. For poor grounding, a ferrite core CMZ7060A-701T with an impedance of 700Ω can be used on-site to improve common-mode rejection capability at 100MHz.