What is the necessary condition for proper operation of a safety switch in electrically-driven equipment?

For a safety switch to operate correctly, it is essential that the footswitch is pressed. This condition ensures that the equipment remains in a safe state and is only activated when the operator is in a position to control it safely. The footswitch typically allows for hands-free operation, enabling the operator to maintain focus on the task while still having the ability to stop the equipment quickly if necessary.

In this context, the other options do not meet the specific requirement for the safety switch's operation. While ensuring that the power cable is connected is generally a prerequisite for any electrically-driven equipment to function, it does not directly influence the safety switch's operation. Similarly, the requirement for all switches to be turned on does not imply that a safety switch will work properly; in fact, many safety switches need specific conditions to ensure safety, which can include a state where certain other switches are not engaged. Lastly, the state of the emergency switches is also crucial, as they might need to be in an active position to ensure all safety measures are in place rather than turned off. Thus, the focus on the footswitch as a necessary condition highlights its role in ensuring safe engagement with the equipment.