Per UL 1077, supplementary protectors can be used for which motor circuit functions?

Per UL 1077, supplementary protectors can be used for which motor circuit functions?

• A. primary protection
• B. overload protection
• C. not suitable for any motor branch-circuit function
• D. short-circuit protection

Answer: (C)

Supplementary protectors are devices that provide protection in addition to a main protective device they accompany. They’re not intended to be the primary protection for a motor branch circuit. Because motor circuits require protections specifically matched to motor startup and operating conditions (like proper motor overload protection and suitable short-circuit protection with correct coordination), a device classified as supplementary under UL 1077 isn’t designed to meet those motor-circuit requirements. Therefore they are not suitable for motor branch-circuit functions. For motor circuits, you’d rely on dedicated motor overload protection and appropriate primary protection that’s coordinated with the motor and starter.

Supplementary protectors are devices that provide protection in addition to a main protective device they accompany. They’re not intended to be the primary protection for a motor branch circuit. Because motor circuits require protections specifically matched to motor startup and operating conditions (like proper motor overload protection and suitable short-circuit protection with correct coordination), a device classified as supplementary under UL 1077 isn’t designed to meet those motor-circuit requirements. Therefore they are not suitable for motor branch-circuit functions. For motor circuits, you’d rely on dedicated motor overload protection and appropriate primary protection that’s coordinated with the motor and starter.