Why is continuity testing of protective bonding important?

• A. It verifies insulation resistance of cables.
• B. It confirms there is a reliable low-impedance path linking exposed conductors to earth.
• C. It measures voltage drop across loads.
• D. It tests fire resistance of cables.

Answer: (B)

The main idea being tested is ensuring a continuous, low-impedance bonding path from exposed conductive parts to earth. This matters because, in a fault, a reliable bond lets fault current flow quickly back to the source through the protective conductor, so the protective device trips promptly and exposed metalwork is kept at safe earth potential. The test checks the continuity by measuring resistance between exposed conductors and earth; a low reading means the bonding path is sound and can carry fault current as intended. The other options don’t assess this path: insulation resistance tests how well cables are insulated, voltage drop across loads looks at normal operation under load, and fire resistance relates to material behavior under heat rather than establishing a safe earth path.