What is the purpose of a continuity test for protective bonding conductors and main bonding?

• A. To verify insulation resistance between conductors
• B. To ensure there is a low-resistance path to earth for safety in the case of a fault
• C. To measure earth leakage current
• D. To check voltage drop under load

Answer: (B)

The main idea being tested is ensuring there is a safe, reliable earth path through bonding conductors. A continuity test for protective bonding conductors and main bonding checks that the bonding network is intact and presents a very low impedance back to earth. This ensures that, if a fault puts a live part in contact with exposed metal, fault current can flow quickly to earth. That rapid current flow makes the overcurrent or residual-current protective devices operate promptly, cutting off the fault and reducing the risk of electric shock or fire.

Protective bonding connects exposed conductive parts to earth so they stay at the same potential, while main bonding links earth and other extraneous conductors to establish a solid, low-resistance path. If the bond is broken or overly resistive, the potential differences during a fault could be dangerous, and protection may not trip fast enough.

This test isn’t about checking insulation (that would be insulation resistance testing), measuring earth leakage (that’s for leakage/earth-leakage tests), or assessing how voltage changes under load (that’s a voltage drop check). It specifically confirms the bonding path stays continuous and capable of carrying fault current safely.