TIA-607-C & NEC 250 - BBC (Backbone Bonding Conductor)

[Rachit]

Per TIA-607-C Section 5.2.6:
Backbone bonding conductor (BBC) - When there are multiple TBBs (Telecom Bonding Backbones, the grounding conductor routed from a Primary Busbar in the MDF to the Secondary Busbar in the IDF), the BBC is employed to interconnect them through the associated busbars, either on the same floor in a multi-story building or in the same general area of a single story building.

I have highlighted the conductor in the attached PDF which is directly from the standard.

This brings up 2 questions for me:
1. Why?, What is the purpose in doing this?
2. Does this not contradict the NEC by creating a closed grounding loop?

Thanks for your help.

 

[don_resqcapt19]

Per TIA-607-C Section 5.2.6:
Backbone bonding conductor (BBC) - When there are multiple TBBs (Telecom Bonding Backbones, the grounding conductor routed from a Primary Busbar in the MDF to the Secondary Busbar in the IDF), the BBC is employed to interconnect them through the associated busbars, either on the same floor in a multi-story building or in the same general area of a single story building.

I have highlighted the conductor in the attached PDF which is directly from the standard.

This brings up 2 questions for me:
1. Why?, What is the purpose in doing this?
2. Does this not contradict the NEC by creating a closed grounding loop?

Thanks for your help.

There is nothing in the NEC that says you can't have a closed grounding loop.

 

[GoldDigger]

There is nothing in the NEC that says you can't have a closed grounding loop.

:thumbsup:
What the NEC does say is that you cannot have a closed loop of grounding conductors and neutrals. To do that would allow some neutral current to flow over the grounding conductor instead.

 

[don_resqcapt19]

:thumbsup:
What the NEC does say is that you cannot have a closed loop of grounding conductors and neutrals. To do that would allow some neutral current to flow over the grounding conductor instead.

It really says you can't bond the grounded conductor to the grounding conductor(s) at more than one location. The drawing the OP provided does not show multiple grounded to grounding connections.

 

[Rachit]

It really says you can't bond the grounded conductor to the grounding conductor(s) at more than one location. The drawing the OP provided does not show multiple grounded to grounding connections.

In the diagram shown, the Secondary Bus Bar is tied into the panel casing of the local electrical panel. Isn't the casing typically tied into the equipment grounding terminal bar inside the panel using a bonding jumper there by connecting the grounding conductor to the grounded conductor in more than one location?