Issue:
Why does APC recommend that each cabinet be bonded to a common ground rather than cascade the ground from cabinet to cabinet?

Product Line:
NetShelter
 
Environment:
All versions and serial ranges.
 
Cause:
Customers may have questions regarding bonding to a common ground vs. cascading.
 
Resolution:

By bonding each cabinet together in a cascading fashion the user relies on all of the cabinet frames in that ground path to reach the building ground.  If one cabinet is removed or one bad connection is made, the ground path is broken.  The easiest way to ensure a solid ground path is to run a common ground wire and connect each cabinet to it. 

There may be a completely different viewpoint in regards to harmonics but that issue is at a very detailed engineering level, and is based on each individual location.
Our concern is that we recommend the most reliable physical method for bonding.