An electrical engineer tuning up a power source (like the Hydrogen Generator in the screenshot) makes it idle for some reason, and it stays idle until the dupe is done tinkering with it. That means if the dupe is still tinkering and he needs to sleep, go to the bathroom, etc, the generator will still remain idle.
Wait for an electrical engineer to tune up a power source. When the dupe is tinkering the power source, it becomes idle until the process is finished. It