New section

[hhsting]

Their is a new section in NEC 2017 section 250.94(B). Would anyone know what size conductor would be needed to bond the bus bar to service grounding electrodes?

 

[infinity]

Although it doesn't specify IMO the intent is to comply with the minimum size in 250.94(A).

 

[hhsting]

If you look at fine wording 250.94(B) says bus needs to have 3 terminations for communications and in addition to other connections while 250.94(A)(2) says it needs 3 connections for intersystem bonding conductors.

To me this means bus can be for other connections such as for grounding electrode conductor transformer so #6 awg is to small no?


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[augie47]

I was of the opinion that it related to 250.64(D) where the same bus was allowed for GEC connections.
In large installations you are likely to have the 250.64 common GEC buss and 250.94(B) allows you to use that for communication.

(You might read the ROPs or ROCs to see the input from the CMP)

 

[Fred B]

250.94(B) is allowing the use of an existing exposed system bonding buss to bond the Communication systems also. So this Bus connection to system would be whatever is required for the system as a whole, and I believe criteria of 250.102 or 250.66 would govern the connection size.
Personally I like option (A) better.

 

[hhsting]

I was of the opinion that it related to 250.64(D) where the same bus was allowed for GEC connections.
In large installations you are likely to have the 250.64 common GEC buss and 250.94(B) allows you to use that for communication.

(You might read the ROPs or ROCs to see the input from the CMP)

That would be possible for small space but in larger buildings like five to seven stories each with communications systems room multiple bus would be needed in each room and each room bus would need to be bonded to service ground bus. Those buses in communication room according to 250.94(B) are not only for communications systems but for other connections. that event bonding conductor that bonds the buses #4 or #6 awg would be too small

Found this

250.94 Bonding for Communication Systems.

In the 2017 NEC, two different methods are permitted for bonding communications systems.

www.electricallicenserenewal.com

 

[don_resqcapt19]

That would be possible for small space but in larger buildings like five to seven stories each with communications systems room multiple bus would be needed in each room and each room bus would need to be bonded to service ground bus. Those buses in communication room according to 250.94(B) are not only for communications systems but for other connections. that event bonding conductor that bonds the buses #4 or #6 awg would be too small

Found this

250.94 Bonding for Communication Systems.

In the 2017 NEC, two different methods are permitted for bonding communications systems.

www.electricallicenserenewal.com

The code simply does not care what size bonding conductor is installed for that purpose and does not even require that grounding/bonding bar to be installed. It is a design issue and not a code issue and whatever the drawings show is fine.