Ground shielding should be grounded at one end rather than both ends because grounding at both ends can cause what?

• A. It always improves shielding
• B. It prevents all noise
• C. It can create ground loops
• D. It eliminates noise completely

Answer: (C)

Ground shielding works best when it provides a path for interference to return to ground without becoming part of the signal path. If you ground the shield at both ends, you create a closed loop between the two grounding points. Any small difference in ground potential or impedance along that path causes current to circulate around the loop. That circulating current can produce voltage drops on the shield or couple into the signal conductors, turning the shield into a conduit for noise instead of a barrier. By grounding the shield at a single point, you minimize the loop area and reduce circulating currents, so the shield more effectively blocks interference from reaching the inner conductors.