PoE lighting circuitry is susceptible to ___, so using shielded cable will help to reduce it.

• A. overheating
• B. fraying
• C. radio frequency interference
• D. electromotive interference

Answer: (D)

The main idea is electromagnetic interference affecting PoE lighting circuits. Shielded cable helps because the metal shield surrounds the conductors and provides a low-impedance barrier to external electromagnetic fields. This containment reduces interference currents entering the data and power lines and minimizes the radiation emitted by the cable itself. In PoE systems, high-frequency switching noise from the power delivery and data signaling can couple into the conductors, so shielding mitigates that noise. Radio frequency interference is a common form of EMI, so shielding specifically helps reduce it. The term electromotive interference isn’t a standard phrase, but shielding targets EMI overall, which includes RF interference, improving reliability and compliance.