Metal gas piping installed in or attached to a building shall be considered bonded when one or more grounding electrodes are used, if the grounding electrode conductor or bonding jumper to the grounding electrode is of sufficient size.

• A. True
• B. False
• C. Not specified
• D. Only when using copper piping

Answer: (A)

Bonding metal gas piping to the building’s electrical grounding system is required to prevent potential differences that could shock someone or create a fault path. The NEC allows metal gas piping to be considered bonded when there is a grounding electrode system installed and a grounding electrode conductor or bonding jumper connecting the piping to that system is properly sized. If the bonding conductor is of sufficient size to carry fault current, the piping is effectively bonded to the electrical system, equalizing its potential with the rest of the system and improving safety. Material of the piping doesn’t change this requirement, and bonding is still achieved as long as the conductor/jumper to the grounding electrode meets the size requirements. If the conductor is undersized or absent, bonding is not achieved.