What is a recommended grounding practice to prevent ground loops in instrumentation wiring?

What is a recommended grounding practice to prevent ground loops in instrumentation wiring?

• A. Run signal and power cables separately and connect shields to a single-point ground
• B. Tie all grounds together at every device
• C. Ground shields at both ends
• D. Do not ground shields

Answer: (A)

Ground loops happen when there are multiple return paths to ground, which lets currents circulate and inject noise into sensitive instrumentation signals. The best way to prevent this is to keep the low-level signal wiring separate from power wiring so their ground paths don’t mingle, and to ground the cable shields at a single point to define a single reference for the shield. This minimizes stray currents and keeps the signal ground stable, reducing hum and interference. Tying all grounds together at every device creates multiple ground paths, inviting circulating currents. Grounding shields at both ends can form a shield loop that carries noise currents along the shield. Not grounding shields removes a key path for shielding, leaving the signal more vulnerable to interference.

Ground loops happen when there are multiple return paths to ground, which lets currents circulate and inject noise into sensitive instrumentation signals. The best way to prevent this is to keep the low-level signal wiring separate from power wiring so their ground paths don’t mingle, and to ground the cable shields at a single point to define a single reference for the shield. This minimizes stray currents and keeps the signal ground stable, reducing hum and interference.

Tying all grounds together at every device creates multiple ground paths, inviting circulating currents. Grounding shields at both ends can form a shield loop that carries noise currents along the shield. Not grounding shields removes a key path for shielding, leaving the signal more vulnerable to interference.