Have a Metal Frame commercial Building,uffer grnd,rebar,ground rods,building steel,water line all are connected at the main disconnect. question is the communications room is on the opposite side of the building 120' and I am getting different opinions on how to bond the TMGB. 800.100 A (4) length shall be as short as practicable 800.100 B2 connected to the nearest accessable location which I take as the building steel.but am being told I need to take it back to the main service entrance.is there anything wrong with taking it accross the building to the main disconnect
Telecommunications Main Grounding Busbar
- Thread starter JFLOAT
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
IMO you would need to comply with 800.100(B)(2)(1) and run the bonding conductor as short as practicable to one of the electrodes that comprise the building GES.
DataCenterGuy
Member
- Location
- New York
TMGB Preferances
TMGB Preferances
The reason you're getting different opinions is that the Telecom industry always wants the TMGB connected back to the Main Building Grounding Point at incoming service. Further, they are often looking for a Ground Resistance of 5.0 Ohms or less. (Hopefully, you're not dealing with some fool who specified a "separate ground".) Without knowing the systems or circumstances, I can't tell how critical this Telecom ground might be considered to be, or how it was specified, but regardless, NEC always trumps TIA. But building steel is generally not well thought of for Telecom grounds, although it certainly has to be inter-connected. Find the "best" ground point you can in the system, within the intent of the Code, which has usually been completely acceptable if run 50-feet or so rather than just to the nearest column. That should make everyone happy.
TMGB Preferances
The reason you're getting different opinions is that the Telecom industry always wants the TMGB connected back to the Main Building Grounding Point at incoming service. Further, they are often looking for a Ground Resistance of 5.0 Ohms or less. (Hopefully, you're not dealing with some fool who specified a "separate ground".) Without knowing the systems or circumstances, I can't tell how critical this Telecom ground might be considered to be, or how it was specified, but regardless, NEC always trumps TIA. But building steel is generally not well thought of for Telecom grounds, although it certainly has to be inter-connected. Find the "best" ground point you can in the system, within the intent of the Code, which has usually been completely acceptable if run 50-feet or so rather than just to the nearest column. That should make everyone happy.
Jhaney
Senior Member
- Location
- owensboro, ky
AT&T only requires a #6 AWG, insulated, copper wire run from the main Panel board, of if the building has an interconnected stel structure than the same size ground wire from there. We don't care what the ground resistance is as long as its there correctly. In all honesty our guys wouldnt know if it was to code or not, let alone how to test it.
DataCenterGuy
Member
- Location
- New York
Telecom Grounds
Telecom Grounds
That's AT&T. But if the spec requires adhearance to TIA, or there's a data center involved, or if there's a spec from a supercomputer manufacturer, guess you would need help if you're unfamiliar with the special Telecom ground requirements and testing methods. Just like medicine, that's why there are specialists in different parts of a field.
Telecom Grounds
That's AT&T. But if the spec requires adhearance to TIA, or there's a data center involved, or if there's a spec from a supercomputer manufacturer, guess you would need help if you're unfamiliar with the special Telecom ground requirements and testing methods. Just like medicine, that's why there are specialists in different parts of a field.
- Status