What is the primary purpose of shielded cable in environments with EMI?

• A. Shield provides EMI protection.
• B. It increases current capacity.
• C. It reduces cost.
• D. It has no effect on EMI.

Answer: (B)

Shielded cable uses a conductive layer around the inner conductors so a barrier exists against external electromagnetic interference. In noisy environments, that shield intercepts EMI and provides a low-impedance path to ground, preventing noise from getting into the signal and reducing the cable’s radiated interference to surrounding equipment. The main purpose is to protect signal integrity by blocking EMI, not to carry more current. The current-carrying capability depends on the conductor size and insulation, while shielding mainly influences noise immunity and impedance characteristics.