What is the surge common-mode test voltage (kV) for the power port of a data center switch?

The surge common-mode test for data center switch power ports is conducted according to IEC61000-4-5 and GB/T17626.5 standards. AC input ports must meet ±4kV (level 4) to ground, and DC -48V input ports must meet ±2kV (level 3) to ±4kV (level 4), selectable. Audiotech's solution: AC ports use a 14D561K varistor (varistor voltage 560V, current capacity 4.5kA) paired with a 2R600L-8X6 gas discharge tube (DC breakdown voltage 600V, current capacity 5kA) to form cascaded protection; the DC 48V port uses a 15KP58CA TVS (VRWM=58V, peak pulse power 15000W) connected in parallel to the input line to ground; the measured residual voltage after passing the 4kV/2Ω combined wave common-mode surge test is <350V.