You are designing a large equipment room (ER) that will house many servers, switches, backup storage drives, and other communications equipment including peripheral devices. To prevent problems from…

Isolated grounding reduces noise coupling and ground-loop interference but does not address the overcurrent hazard on neutral conductors caused by harmonic accumulation.

Switching power supplies generate odd-order triplen harmonics (3rd, 9th, 15th) that add arithmetically on the neutral conductor in a 3-phase system rather than canceling as balanced fundamental currents would. This can cause the neutral to carry 173% or more of the phase conductor current, so NEC and BICSI TDMM standards recommend oversizing the neutral conductor - typically to 200% of phase conductor ampacity - along with oversized grounding conductors to safely dissipate this excess current and prevent fire or insulation failure.

Surge protection on power supplies mitigates transient voltage spikes; it does not reduce or handle sustained harmonic current loading on the neutral conductor.

A separate 3-phase feeder isolates the ER load from the building distribution but does not resolve the internal harmonic current buildup on the neutral conductor within the ER.

Power filtering at the service panel can attenuate incoming harmonics but is not the standard primary countermeasure for harmonic-related neutral overloading inside an equipment room.