What is the purpose of temporary protective grounding?

• A. To relieve voltage stress by redirecting current away from protected equipment
• B. To provide a definite ground reference and prevent backfeed or stray voltages on a circuit during maintenance on de-energized equipment
• C. To permanently bond all equipment to earth for normal operation
• D. To reduce the need for continuous monitoring during maintenance

Answer: (B)

Temporary protective grounding is used to create a definite earth potential on exposed conductors when work is done on equipment that is de-energized. Even after a circuit is opened, stored energy, capacitance from cables, or connections from other sources can put a dangerous voltage on conductors. Attaching a grounding path to the equipment and tying it to earth provides a low-impedance route that bleeds off any residual or induced voltage and keeps the circuit at earth potential. This prevents shock hazards for workers and also gives a clear path for fault current to flow if a fault somehow occurs, helping protective devices trip and improve safety. After maintenance, the temporary grounds are removed once the system is confirmed de-energized and locked out. Permanent bonding serves normal operation, not the specific purpose of temporary protective grounding.