Which component is used to fasten a grounding conductor to a metal structure?

• A. Bolt
• B. Nut
• C. Lug
• D. Clamp

Answer: (C)

When connecting a grounding conductor to a metal structure, you need a dedicated termination that provides a secure, low-impedance bond. A grounding lug is designed for this purpose. It acts as a formal terminal to receive the conductor and fasten it firmly to the structure, usually with a bolt or screw, and is sized and rated for grounding use. This ensures consistent electrical contact, good mechanical security, and resistance to loosening or corrosion.

Using a plain bolt or nut alone doesn’t give a dedicated electrical termination and can loosen or degrade the connection over time. A clamp might secure a wire in some cases, but it isn’t as reliable a termination for grounding as a purpose-made lug, which is specifically intended for bonding conductors to metal surfaces.