Grounding gas piping system?

[The Iceman]

Article 250.52 (B) (1) Metal underground gas piping sysem is not permitted for grounding. I can understand that you don't want to provide a low impedance path for lightning to a gas pipe. But 250.106 (B) tells use to bond gas pipes in a building or structure that are likely to become energized, and bond it to the service equipment enclosure, grounded conductor at the service, or the GEC. Lightning doesn't just take the path of least resistance, it takes every available path. In doing this don't we provide a path for lightning to the metal gas piping system?

 

[mdshunk]

In doing this don't we provide a path for lightning to the metal gas piping system?

Yup, but the magnitude of the current will be much less than if, for instance, it was your sole electrode.

 

[nakulak]

yep, I wonder the same thing everytime I bond gas pipes, especially on roofs. not only lightning - they could also provide a lower impedance path when a fault occurs too. However, in deference to the code, you must realize that even though the pipe is potentially being energized, the gas is not supposed to be in a state wherein it is flammable (the gas in the pipe is not supposed to be in the explosive limits)

 

[augie47]

In bonding the INTERIOR piping system, you are normally not effecting the undeground system since most gas meters have dielectric connections to prevent a connection to the underground pipe. I would think this would prevent any current flow.