How to solve eft interference on pcb

The EFT test of power port is divided into two test modes: line-line and line-ground. You are conducting a line-to-ground test.

When EFT signal is applied, the voltage waveform on the tested power line will change, which will be transmitted to the system by supplying power to the product. As long as your system uses this power signal line, the system will be affected. This has nothing to do with the shell material.

EFT originally simulates the influence of inductive load switching, so it belongs to inductive coupling, not capacitive coupling.