Which description best defines bonding in electrical systems?

• A. Bonding equals grounding.
• B. Bonding increases impedance.
• C. Bonding connects exposed metallic parts to maintain electrical continuity and equal potential.
• D. Bonding is only for outdoor circuits.

Answer: (C)

Bonding is the practice of tying exposed metallic parts together so they all share the same electrical potential and stay connected with a low-impedance path. This keeps metal surfaces—like conduits, enclosures, pipes, and equipment—from developing dangerous voltage differences relative to each other. When a fault occurs and electricity could energize a metal part, bonding ensures that all connected metal parts are at nearly the same potential, reducing shock risk and helping a protective device trip quickly.

This is different from grounding, which is about connecting the system to earth to stabilize voltages relative to the earth. Bonding focuses on maintaining continuity and equal potential among metallic parts, not just attaching them to the earth. The description that emphasizes connecting exposed metallic parts to maintain electrical continuity and equal potential best captures what bonding does. Bonding aims for a low-impedance pathway, not an increase in impedance, and it applies in more situations than just outdoor circuits.