In cold water distribution, what does bonding/grounding of metal piping involve, and why is it important?

• A. Electrical bonding to provide a continuous path to ground to prevent shock hazards and equipment damage; required by electrical code.
• B. Painting metal pipes to prevent rust.
• C. Placing insulation around pipes only for thermal purposes.
• D. Connecting pipes to a water treatment chemical.

Answer: (A)

Bonding metal piping means tying the metal water service and connected metal parts to the building’s electrical grounding system so they all share the same electrical potential. A bonding conductor runs from the electrical service grounding electrode (the panel) to the metal water pipe, creating a continuous low-impedance path to earth.

This is important because if a fault energizes a pipe or a connected appliance, the fault current has an easy route to ground. That quick path helps the overcurrent protection (breaker or fuse) trip promptly, reducing the chance of a dangerous electric shock if someone touches the pipe and another grounded surface. It also prevents dangerous voltage differences between different metal parts of the system.

This bonding is required by electrical code, using properly sized conductors and secure connections, and it’s focused on electrical safety rather than cosmetic or thermal purposes.