Distinguish between bonding and grounding in a building electrical system.

• A. Grounding connects the system to earth; bonding connects conductive parts together to maintain the same potential.
• B. Bonding connects to earth; grounding connects components together.
• C. Grounding and bonding are the same.
• D. Bonding only applies to structural metal parts; grounding applies to electrical circuits.

Answer: (A)

The key idea is that grounding and bonding serve different safety roles in a building’s electrical system. Grounding (earthing) establishes a reference point and a path for fault current to reach the earth. This usually involves a grounding electrode and a grounding conductor back to the service equipment, helping protective devices trip when something goes wrong.

Bonding, on the other hand, is about keeping conductive parts at the same electrical potential. By tying metal components—like enclosures, conduits, water pipes, and other metallic systems—together and to the grounding system, bonding minimizes dangerous voltage differences that could shock someone who touches multiple metal surfaces.

So, grounding connects the system to earth to provide a fault-current path and reference, while bonding connects conductive parts to maintain a common potential. These functions work together to enhance safety.