In a building with no intersystem bonding termination, the bonding conductor or grounding electrode conductor is required to be connected to the nearest accessible location on any but which of the following?

• A. A metal gas piping system
• B. An electrical service equipment enclosure
• C. A metal water piping system
• D. A telephone or communications network

Answer: (A)

Equipotential bonding and grounding are about ensuring that different metallic parts of a building share the same electrical potential so fault currents have a path back to the source and hazards are minimized. When there is no intersystem bonding termination, the bonding conductor or grounding electrode conductor must be connected to a readily accessible point on conductive parts that can serve as a bonding path—such as the electrical service equipment enclosure, a metal water piping system, or a telecommunications network enclosure or equipment. Gas piping, while it has its own bonding rules, is not the bonding point used in this scenario. Bonding to water piping or service equipment or communications equipment ensures a reliable, low-impedance path for fault currents and keeps those systems at the same potential, reducing shock risk.