Which device surrounds a wire and detects the electromagnetic field due to electricity passing through the wire?

• A. Current sensing relay
• B. Pseudopoint
• C. Timed override initiator
• D. Incremental output

Answer: (A)

The test is about sensing current by magnetic coupling. A device that encircles the conductor picks up the magnetic field created by the current flowing through the wire and converts that magnetic interaction into an electrical signal for the control system. This is exactly what a current sensing relay does: it surrounds the wire and responds to the electromagnetic field generated by the current, providing a signal or trip action without breaking the circuit.

The other options don’t fit this sensing method. A pseudopoint isn’t a real measurement device. A timed override initiator is a control action, not a current sensor. An incremental output describes a type of signal used for position or event counting, not current detection through magnetic coupling.