Which statement best describes the role of protective earth in equipotential bonding?

• A. It carries current only during normal operation
• B. It connects exposed and extraneous parts to maintain equal potential
• C. It is optional in modern installations
• D. It is used to carry signal data

Answer: (B)

The protective earth in equipotential bonding is used to keep exposed conductive parts and extraneous conductive parts at the same potential. By tying metalwork and other conductive items to the earth, any insulation fault that makes a live surface appear on metal will cause fault current to flow through the earth path. This rapid current flow triggers protective devices to disconnect the circuit, reducing the risk of electric shock. Keeping these parts at equal potential also minimizes dangerous touch and step voltages that could occur if different metal parts floated at different voltages.

Under normal operation, the protective earth isn’t meant to carry working current; its role is safety in fault conditions. It is required in modern installations and isn’t used to carry data signals either.