Ground bus requirement for electrical closet, Chiller room, IDF and rest room

[Leo Li]

Hello Sir， when I reveiew US local design firm drawings, I fund there is no ground bus in Chiller room, Electrical closet, IDF, elevator pit and rest room so I gived them comments to add ground bus as bleow, but our design firm replied is " NOT REQUIRED PER US NATIONAL ELECTRIC CODE.". Yes As I checked in NEC thete items clearly to to say "to add ground bus in Chiller room or rest room etc.;..." but I wolud like to know how is these equipment to groud if no local ground bus ? In China all these equipment, electrical panel or rest room metal pipe should be grounded through local ground bus. Thanks in advance!

 

[tom baker]

You cannot compare our NEC standards to yours. Your design firm is correct.

 

[Leo Li]

You cannot compare our NEC standards to yours. Your design firm is correct.

Thanks, Tom！So I wolud like to know if those equipment metal enclusre ground through feeder ground conductor and no need our called "local repeated ground", correct? And also I want know how to achieve tolilet room metal tube ground?

 

[ron]

No redundant ground bar is required. Minimum grounding per the NEC is via the equipment grounding conductor (ECG) in the feeder or branch circuit.

I have never heard of a toilet room metal tube ground. Anything in a bathroom that is likely to become energized has an EGC in its circuit and is grounded in that manner.

 

[Leo Li]

No redundant ground bar is required. Minimum grounding per the NEC is via the equipment grounding conductor (ECG) in the feeder or branch circuit.

I have never heard of a toilet room metal tube ground. Anything in a bathroom that is likely to become energized has an EGC in its circuit and is grounded in that manner.

thanks! So how is those equipment metal enclosure ground such as boiler, Chiller etc.; ? Also through ECG in feeder？

 

[tom baker]

Yes via the egc in branch ckt to equipment.

 

[don_resqcapt19]

All of our circuits require some type of equipment grounding conductor and that EGC is connected to the non-current carrying parts of the electrical equipment.

 

[tom baker]

Perhaps the toilet room metal tube is a metal water line. You’ll need to review art 250 on grounding electrodes to see if the metal tube is an electrode or if not bond per 250.104. If tube is an electrode ground per section 250.66

 

[Leo Li]

Perhaps the toilet room metal tube is a metal water line. You’ll need to review art 250 on grounding electrodes to see if the metal tube is an electrode or if not bond per 250.104. If tube is an electrode ground per section 250.66

thanks!