Lighting contactors are frequently controlled by a two-wire pilot device such as:

• A. Pressure Switch
• B. Thermostat
• C. Pushbutton
• D. Time Clock

Answer: (D)

Lighting contactors are energized when a pilot device closes the control circuit to the coil. A two-wire pilot device provides that closure without needing a separate power feed for the pilot circuit. A time clock is a natural fit here because it is designed to switch the control circuit on and off on a schedule. When the clock’s contact closes at the programmed time, current flows to the contactor coil and the lights come on; when the clock opens, the coil de-energizes and the lights go off. This makes time clocks a common, automated way to control lighting. While a pushbutton can also control a contactor, it is typically used for manual local control rather than automatic timing; pressure switches or thermostats serve other purposes in different systems.