In schematics, the symbol OL denotes which component?

• A. OverloadRelay
• B. Overload Switch
• C. Open Loop Sensor
• D. Overcurrent Protector

Answer: (A)

OL in schematics points to the overload protection device used with motor starters—the overload relay. This protective device watches the motor’s current (and often temperature) and will trip the circuit if the motor is overloaded, preventing damage by opening the circuit. You’ll typically see it wired in series with the motor starter, with its normally closed contacts coordinating with the contactor so power is cut when an overload occurs. This label is a concrete way to distinguish the protective relay from other devices like a manual or automatic overload switch, an open-loop sensor, or a generic overcurrent device, which would use different markings.