Just goes to show that there are no real standards in the RV industry. I have (had) a switch like that (unlabeled) that is there because my rig that should have been built as a 50A rig was sold as a 30A unit. We have an electric fireplace that I enjoy using in the mornings when it is cool (just about every day when we travel). I also use the microwave in the morning preparations, but you cannot use both at the same time. You need to flick the switch near the door to decide what you want to use - microwave or the fireplace, and of course, every time you lose power with the microwave, you need to reprogram the clock before you can use it.
Honestly I'd never have purchased the rig had I known that was the case (my bad). My solution was to modify my rig to 50A service - used it on our long trip just completed and it was such a pleasure. I can now use the the fireplace, microwave, and anything else in the rig without having to resort to switching.
The take-home lesson - make sure you look at every possible "feature" in a rig and ask plenty of questions in a forum like this one - it can save you lots of grief in the long run. For the most part, the salesmen just want to make the sale and do not care once they get your money.
PZ
