What is the required function of a motor branch circuit short-circuit ground-fault protection device?

The required function of a motor branch circuit short-circuit ground-fault protection device is to open during ground faults or short circuits. This device is designed to provide protection for the motor and the wiring associated with it by detecting excessive current flow that can occur during faults such as a ground fault or short circuit.

When the current surpasses a certain threshold, this device quickly interrupts the circuit, disconnecting the power to the motor. This action prevents damage to the motor and reduces the risk of fire or electrical hazards associated with these fault conditions. The timely disconnection from the power source helps ensure safety and reliability in electrical systems.

In contrast, other functions listed, such as opening during maintenance or remaining closed while the motor is starting, do not align with the primary purpose of short-circuit ground-fault protection. Similarly, activating only during overloads suggests a different type of protection that is not focused on the immediate dangers posed by short circuits and ground faults.