Kast, let me try to clarify a little bit. If you're running your generator through the breaker box, you need a switch. If you're running appliances directly from the generator, by-passing the breaker box and plugging directly to the generator, there is nowhere else the electricity can travel to. Think in terms of a path. Create a map for your electricity and direct it to where you want it to go. When you wire a generator to a breaker box without a cut-off switch, the electricity will travel through all the open paths, one of which leads back to the wire on the pole on your street. What the switch does is cuts off that path, containing the electricity to the connections you have chosen (well pump, sump-pump, frig, stove, etc.... whatever your priorities are). The switch acts in the same way that your breaker switches work. If you're going to install a new kitchen light, you go to the breaker box and cut off that switch to the kitchen. You perform the install with all the wired dead. So , let's say for example, you're going to run your well pump from your generator in an outage. Your well pump does not have a plug; it works directly off your breaker box. So you'd need to run your generator through your breaker box to power the well pump, right? Without a cut-out switch, electricity will flow back into the lines outside your home, creating a safety issue for anyone working on those lines on your street. That's what 'back-feeding' is. If you're going to run an extension cord to a self contained generator, plugging your stove directly into the unit, there is no risk of back-feed. You just need to match need for feed, which a whole different subject.