What component must be opened by the disconnecting means for a motor?

The correct component that must be opened by the disconnecting means for a motor is all ungrounded conductors. In electrical systems, especially those involving motors, the disconnecting means is designed to ensure that all ungrounded conductors are interrupted to safely isolate the motor from the source of power. This is critical for safety reasons as it prevents any potential electrical shock or accidental re-energization of the motor while maintenance or repairs are being performed.

When all ungrounded conductors are opened, it ensures that the electrical circuit is completely de-energized. It is important for the protection of both the personnel working on the motor and the equipment itself. If only the main supply line or only certain conductors were opened without addressing the ungrounded conductors, there would still be a risk of injury or equipment damage due to the presence of residual voltage on the motor's windings.

Although grounded conductors serve a vital role in electrical systems by directing fault currents safely to the ground, they do not need to be disconnected to ensure safety during maintenance of the motor. Non-metallic conduits, while used for protection of wiring, do not pertain to the disconnecting method as they do not interact directly with the electrical isolation process required for