Device preventing operation under unsafe conditions.

Device preventing operation under unsafe conditions.

• A. Self-Closing Door
• B. Safety Switch
• C. Runway Enclosure
• D. LULA

Answer: (B)

A safety switch is designed to stop the machine when a safety condition is violated. Wired into the control circuit, it trips and cuts power if an access door, gate, or protective cover is opened or misaligned, preventing startup or continued operation. This is exactly the function of a device that prevents operation under unsafe conditions. A self-closing door helps ensure doors aren’t left open but doesn’t automatically interrupt the control circuit to stop the machine. A runway enclosure provides a physical barrier rather than an operational interlock. A LULA is a type of elevator, not an escalator safety device.

A safety switch is designed to stop the machine when a safety condition is violated. Wired into the control circuit, it trips and cuts power if an access door, gate, or protective cover is opened or misaligned, preventing startup or continued operation. This is exactly the function of a device that prevents operation under unsafe conditions.

A self-closing door helps ensure doors aren’t left open but doesn’t automatically interrupt the control circuit to stop the machine. A runway enclosure provides a physical barrier rather than an operational interlock. A LULA is a type of elevator, not an escalator safety device.