One way to avoid EMI problems is to terminate unused conductors at both ends.

One way to avoid EMI problems is to terminate unused conductors at both ends.

• A. Ground shield at one end
• B. Terminate, unused conductors at both ends
• C. Use thicker insulation
• D. Install a shielded conduit

Answer: (B)

Unused conductors left floating can act like tiny antennas, both picking up outside interference and radiating noise into the cable system. Terminating those unused conductors at both ends gives them a defined condition, removing the free ends that would otherwise interact with EMI. By tying or capping unused wires at both ends, you prevent stray signals from propagating along the run and reduce the chance of EMI affecting or leaking from the circuit. Grounding the shield at one end helps reduce EMI entering or leaving through the shield, but it doesn’t address the risk from unused conductors inside the cable. Using thicker insulation doesn’t stop the conductors from picking up or radiating interference. Installing a shielded conduit changes the environment around the run to cut down external EMI, but it doesn’t eliminate EMI paths created by unused conductors within the cable.

Unused conductors left floating can act like tiny antennas, both picking up outside interference and radiating noise into the cable system. Terminating those unused conductors at both ends gives them a defined condition, removing the free ends that would otherwise interact with EMI. By tying or capping unused wires at both ends, you prevent stray signals from propagating along the run and reduce the chance of EMI affecting or leaking from the circuit.

Grounding the shield at one end helps reduce EMI entering or leaving through the shield, but it doesn’t address the risk from unused conductors inside the cable. Using thicker insulation doesn’t stop the conductors from picking up or radiating interference. Installing a shielded conduit changes the environment around the run to cut down external EMI, but it doesn’t eliminate EMI paths created by unused conductors within the cable.