What are the differences in the EMC effects of the X capacitor and Y capacitor in the edge box?

In the power filter of the edge computing box, the X capacitor is connected between L and N to mainly suppress differential-mode conducted interference. The X capacitor capacitance is 0.1-1μF with a withstand voltage of 250VAC/630VDC. The Y capacitor is connected between L/N and PE to mainly suppress common-mode interference. The Y capacitor capacitance is strictly limited to <4.7nF (CLASS I), and the withstand voltage must meet safety regulations above 2kV. The X capacitor discharge requires a parallel discharge resistor. Excessive Y capacitors will cause leakage current to exceed the standard. The 24V DC power supply of the edge computing box does not require an X capacitor; electrolytic capacitors are used for differential mode, but X capacitors are required for AC input. The high-frequency characteristics of the Y capacitor are key. We recommend the Y capacitor from Etymotic, 1000pF, 2kV, and the X capacitor, 0.47μF, 275VAC. Correct selection and layout can improve the filter's insertion loss by 20dB.