How does bonding connect to grounding at the service equipment?

• A. Bonding connects non-current-carrying metal parts to the grounding system to maintain a common potential, while grounding provides the reference to earth.
• B. Bonding and grounding are completely unrelated.
• C. Bonding is the same as grounding.
• D. Bonding uses plastic to isolate metals.

Answer: (A)

Bonding and grounding at service equipment serve two related but distinct roles. Bonding keeps all exposed non-current-carrying metal parts tied together so they stay at the same electrical potential. This prevents a dangerous voltage difference between parts that a person could touch if a fault occurs. Grounding provides a connection to the earth, establishing a reference point and a low-impedance path for fault current to flow back to the source so the overcurrent protective devices can clear the fault quickly. At the service equipment, bonding ties the metal parts to the grounding system and earth, creating a single potential for all those parts and ensuring a reliable fault path. This explanation shows why bonding is about equalizing potential among metal parts, while grounding is about linking the system to earth for fault clearance. The other options misstate their relationship or introduce incorrect ideas, such as isolation with plastic.