What is a manually operated device used for operating a transfer switch called?

The term referred to in the context of a manually operated device used for operating a transfer switch is specifically aligned with the definition of a manual isolation switch. This type of switch is designed to allow an operator to manually isolate electrical equipment from the electrical supply, ensuring safety during maintenance or in cases of fault conditions.

In relation to transfer switches, which are used to switch power supply sources, a manual isolation switch enables the user to disconnect the power source safely before engaging or disengaging the transfer switch. This is crucial for preventing electrical hazards and ensuring proper operation without the risk of electric shock.

The other options provided, while they may have their own functions within electrical setups, do not designate devices specifically meant for the manual operation of transfer switches. Thus, the correct identification of this device is aligned with its function within safe electrical practices and adheres to the language defined within the National Electrical Code.