How to isolate the protective ground and signal ground of a data center switch?

Data center switch protective ground (PE/chassis ground) and signal ground (GND) need to be isolated to balance safety and EMC. Recommended solution: provide a common-mode return path via capacitive coupling at high frequencies, and maintain isolation at low-frequency DC frequencies. Typical design: a 1nF/2kV ceramic capacitor (C0G material) and a 1MΩ bleeder resistor are connected in parallel between signal ground and chassis ground; the capacitor's resonant frequency should be >100MHz, and the equivalent series resistance <0.1Ω. Audiotech recommends using a high-voltage capacitor; this solution can suppress 85% of transient interference from chassis ground while meeting safety withstand voltage tests. Note that directly shorting the signal ground and chassis ground is strictly prohibited to prevent ground loop interference.