As your reply clearly states that communication equipment (racks, cabinets) shall have separate ground busbar that the one for electrical equipment (Panelboards, PDUs), EIA-J-STD-607-A standard in 18.104.22.168 states that panelboards within the same room or space shall be bonded to the TMGB (Telecommunication Main Ground Busbar). This looks contradicting to me. I really appreciate if you can give more explanation on this.
In the typical data center you will often have many different ground bars in use throughout the facility. For example, in the electrical room, you will not only have the green wire low-impedance fault current path required by the NEC, but you ,may also have a safety ground system with multiple ground bars used to bond the various metallic objects found within the room (electrical panels, conduit, air handling equipment, fire suppression, doors, gates, fences, etc.).
In your computer room, you will have a requirement for a copper ground bar to be installed inside each computer server rack, and then an additional ground bar(s) mounted on the wall of the server room that will be used to bond all the server rack ground bars together, along with the conduit bonds, air handling equipment bonds, door bonds, UPS power supply, etc. This server room ground bar(s) must in turn be bonded back to the main ground bar in your Telco room, and back to the first service disconnect in the main electrical room. There are also typically requirements for dedicated 5-ohm or less grounding electrodes that must be bonded to the server room ground bar(s).
You may have additional ground bars used for the bonding of the lightning protection system, back-up generator systems, electrical substations, equipment chassis, and many more. All of these ground bars and grounding systems must be bonded to each other in manner that does not cause additional problems with ground loops, resulting in harmonics and electrical interference.
Please feel free to give us a call at 310-318-7151 California time and someone will be happy to speak with you about your project free of charge.
The Engineering Team at E&S Grounding Solutions
Photo credit: E&S Grounding Solutions