What is the function of a bonding jumper in a service panel?

• A. Bonding jumpers connect hot bars to each other.
• B. Bonding jumpers connect metallic parts to equalize potential and reduce shock risk.
• C. Bonding jumpers cut power during faults.
• D. Bonding jumpers provide fusing protection.

Answer: (B)

Bonding jumpers are used to connect metal parts of the electrical system so they sit at the same electrical potential. This equalizes voltage between the enclosure, conduits, and other metallic components, which reduces the shock hazard if a fault causes electricity to come into contact with any of these surfaces. By providing a low-impedance path back to the source, the bonding path helps fault currents reach the overcurrent device quickly so it trips and clears the fault. This safety role is different from cutting power or providing fusing protection, and it’s distinct from bonding hot bus bars together, which are part of the energized circuit rather than the safety grounding of metal parts.