What is the required grounding resistance (in Ω) for a data center switch?

The grounding resistance of data center switches directly affects lightning surge protection and electromagnetic compatibility performance.

Standards require: IEC62305 and GB50057 for grounding system resistance ≤10Ω, while NEBS GR-1089 for telecommunications requires cabinet grounding resistance ≤5Ω, and core data centers require ≤1Ω. Actual measurements show that when the grounding resistance is reduced from 10Ω to 1Ω, surge residual voltage decreases by 40% and common-mode radiation decreases by 12dB.

Design goals: The resistance from the switch's individual grounding terminal to the cabinet grounding busbar should be <0.1Ω, using 20mm wide copper braided tape with a length <1m; the resistance from the cabinet to the ground should be <5Ω. Audiotech recommends that the grounding loop design should have a 20% margin.