Intersystem bonding

[smallfish]

An additional building on the same property is supplied with an outside multiwire branch circuit which includes an equipment grounding conductor. This building does not have nor need a grounding electrode. 2005NEC Sec. 250.32.
This outside multiwire branch circuit's disconnecting means is located not on this additional building but on an adjacent building 25 feet away. 2005NECSec.225.32.
An overhead Coaxial Cable (for internet use) is dropped to this additional building and connected on the outside wall to a fitting with a terminal for a wire for bonding/grounding. Another coaxial cable that enters the additional building is also connected to this fitting.
Is it code to run a 6AWG copper wire from this fitting 25 feet underground to the grounding electrode system of the service supplying this additional building? Or must a ground rod be driven at the additional building and bonded to both the fitting and to the grounding electrode system of the service supplying this additional building?
Thanks

 

[smallfish]

Intersystem bonding

The code reference I listed in my question includes the exception #1 to 2005NEC Sec.225.32. This may explain the permission of the installation of the disco elsewhere on the premises.

 

[augie47]

I think it's possible that your scenario isn't fully covered by 250.94, but my opinion would be that you would run the conductor back to the service at the feed building.

 

[acrwc10]

An additional building on the same property is supplied with an outside multiwire branch circuit which includes an equipment grounding conductor. This building does not have nor need a grounding electrode. 2005NEC Sec. 250.32.
This outside multiwire branch circuit's disconnecting means is located not on this additional building but on an adjacent building 25 feet away. 2005NECSec.225.32.
An overhead Coaxial Cable (for internet use) is dropped to this additional building and connected on the outside wall to a fitting with a terminal for a wire for bonding/grounding. Another coaxial cable that enters the additional building is also connected to this fitting.
Is it code to run a 6AWG copper wire from this fitting 25 feet underground to the grounding electrode system of the service supplying this additional building? Or must a ground rod be driven at the additional building and bonded to both the fitting and to the grounding electrode system of the service supplying this additional building?
Thanks

Is your cable bonded at the service on the main building already ? If yes then you don't have a need to add the #6. 25ft is not far enough to cause an issue.

 

[hurk27]

This is one of those rare configurations that kind of fell through the cracks, as I have never found any definite answer to this question, at any of my IAEI sectional meetings, from what I can gather, is the grounding electrode system for a separate building is a totally separate electrode system and does not require the intra-bonding between the first building and a second building's electrode system
250.50.

at each building or structure served,

So bonding of communication equipment in 800.40 seems to really leave an open hole in these requirements when there is no electrode system for a building because of the 250.32(A) exception (for only one circuit), so about the best answer I can give is to bring out a equipment grounding conductor to a driven electrode and bond your grounding block to it and your done. see also 250.32(B)(1)

 

[hurk27]

Now from a point of view as far as protection from lightning, any conductors longer then 20' will usually not have much if any effect on a lightning strike, so again maybe this is why there is no requirement for intra-system bonding, lightning is a very high frequency event, and conductors longer then 20' will act like an open circuit to it anyway.
Note that this length was also incorporated into 800.40 also.