Which shielding grounding practice helps prevent ground loops in sensor wiring?

• A. Ground at the signal end.
• B. Ground at both ends.
• C. Do not ground shield.
• D. Ground at a single point.

Answer: (D)

Ground loops happen when shield connections create a closed path between different grounds. If the shield is connected to ground at more than one point, current can flow along the shield due to differences in ground potential, turning the shield into a loop that carries noise into the sensor signal. By grounding the shield at a single point, you provide a solid ground reference for shielding without creating a loop current path. The shield stays effective at blocking EMI while avoiding the stray currents that would flow if grounded at both ends or left ungrounded. Grounding at only one point thus minimizes loop currents and keeps the signal cleaner.