Pipe Truss bonding

[patpappas]

A new steel truss (not connected to any bldg.) is installed over a roadway, 4 - 3" PVC homeruns (each w/300mcm) w/RMC 90's and four metal pull boxes installed on the truss are in each homerun, there are 2 - 10" chilled water lines across the truss all with victulic fittings, I see the truss as isolated, the metal pull boxes could energize the metal truss I see this as a violation of 250.104 (C), 2005 NEC and should bond to the chiler unit with a 3/0 due to the total conductor size. Anyone with any thoughts.

 

[petersonra]

A new steel truss (not connected to any bldg.) is installed over a roadway, 4 - 3" PVC homeruns (each w/300mcm) w/RMC 90's and four metal pull boxes installed on the truss are in each homerun, there are 2 - 10" chilled water lines across the truss all with victulic fittings, I see the truss as isolated, the metal pull boxes could energize the metal truss I see this as a violation of 250.104 (C), 2005 NEC and should bond to the chiler unit with a 3/0 due to the total conductor size. Anyone with any thoughts.

250.104(C) Structural Metal. Exposed structural metal that is interconnected to form a metal building frame and is not intentionally grounded and is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or the one or more grounding electrodes used.

I don't think the truss qualifies as part of the building frame.

 

[LarryFine]

250.104 doesn't seem to apply to non-building metal. I would think that properly bonding the pull boxes would suffice. You know, the circuit likley to energize the metal.

 

[patpappas]

I had not thought about if the boxes are properly bonded then the truss should be fine, thank you for your reply.