6.13 Electrical Bonding and Grounding.

6.13.1 Each aboveground portion of a gas piping system that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping shall be considered to be bonded when it is connected to gas utilization equipment that is connected to the equipment grounding conductor of the circuit supplying that equipment.

6.13.2 Gas piping shall not be used as a grounding conductor or electrode.

6.14 Electrical Circuits.

Electrical circuits shall not utilize gas piping or components as conductors.
Exception: Low-voltage (50 V or less) control circuits, ignition circuits, and electronic flame detection device circuits shall be permitted to make use of piping or components as a part of an electric circuit.

6.15 Electrical Connections.

6.15.1 All electrical connections between wiring and electrically operated control devices in a piping system shall conform to the requirements of NFPA 70, National Electrical Code. (See Section 6.13.)

6.15.2 Any essential safety control depending on electric current as the operating medium shall be of a type that will shut off (fail safe) the flow of gas in the event of current failure.
Joe Tedesco, NEC Consultant