Power lockouts are necessary for which of the following situations?

The necessity of power lockouts is primarily associated with ensuring safety during maintenance or repair of equipment. The correct scenario for implementing power lockouts is when servicing areas where hazardous energy sources are present, such as in an x-ray room. Lockout procedures help prevent accidental power activation while personnel are working on the equipment, thereby reducing the risk of injury.

When considering other options, while it's important to have safety protocols for any medical device that poses risks, the most critical aspect is that x-ray rooms can involve high voltage and radiation hazards, making power lockouts necessary in those environments. The implication of moving a device that isn't large enough to require lockout does not take into account the potential hazards associated with servicing that device, especially if it is connected to a power source. Hence, lockouts are not solely determined by the size or voltage of the equipment but by the context and potential risks associated with its service.