Oh boy, is this one of my latest hot buttons. I'm going to assume that this situation involves a UPS.
Either use the building ground 100% or use a UPS's ground which effectively isolates the ground for all devices attached to the computer. In my travels, what I see is that people use a UPS for the actual computer, yet they plug the printer, monitor, etc. into non-backup power. It is all or nothing when using a UPS, PERIOD!
The supposedly-protected electronic equipment, be it phone systems, computers, or whatever are now being hit in two directions under lightning/surge conditions. Double-whammy exposure and double risk for damage. Secondary surge protection devices are just a marketing ploy that actually increases equipment damage in my book.
These devices are sold with "guarantees" for the protected equipment from surge damage, but any claims filed are impossible to collect upon. These guarantees are so loosely-written that the manufacturers of these devices rarely pay out a dime. I've never succeeded in a single claim on a customer's behalf.
Surge "protectors" can only do so much when they are expected to do what they are not designed to do when placed in an isolated environment.
