Which component connects the solenoid, door switch, and lock switch?

• A. Top Terminal Limit Switch
• B. Obstruction Sensing Device
• C. Interlock Wiring
• D. Call/Send Control Station

Answer: (C)

Interlock wiring coordinates the safety components so the escalator can only run when the door interlock is satisfied. The solenoid controls the locking mechanism, the door switch confirms the door is closed, and the lock switch verifies the lock is engaged. The interlock wiring provides the electrical connections that feed these signals to the control circuit, forming a safety chain. When the door is closed and the lock engaged, the circuit is completed and the drive can energize. If the door is open or the lock isn’t engaged, the circuit opens and operation is prevented to protect riders. The other devices serve different safety roles—top terminal limit switches stop at the end of travel, obstruction sensing detects objects in the path, and the call/send station is for operator control—not for tying the door and lock actions together.