What is the purpose of a grounding conductor?

• A. To reduce line impedance.
• B. To provide a path to earth for fault current.
• C. To support the cable.
• D. To carry signal.

Answer: (B)

The main idea is that a grounding conductor provides a safe, low-resistance path to earth for fault currents. When something faults—like a hot conductor touching a metal enclosure—the fault current flows through the grounding conductor to the earth. Because that path is intentionally low impedance, a large enough fault current quickly flows to trigger the overcurrent protection (breaker or fuse) and shut the circuit off, reducing the risk of electric shock and fire. It also helps keep metal parts at near-earth potential, which is another safety benefit.

This isn’t about reducing line impedance, which comes from the conductors and components in the normal circuit. It doesn’t serve to physically support the cable, and it isn’t meant to carry signals in regular operation (ground can be used as a reference in some systems, but that’s not its primary purpose).