Originally Posted by Henukaw
So, I should be able to step it down to 30 amp service, and use the double pole 30 amp breaker in place of the 100 amp I take it...? I was considering going this route as 30 amps would be enough for our needs at this point in time. I'd like to have the vercatility 50 amps brings, but I can easily change that in the future.
I'm currently running four zones, one 20A (kitchen), and then three 15A (entertainment, bath, and living area). This will provide enough room to run everything comfortably around the bus. I like the idea of having a "summer room" supplied via outdoor near the passenger side sometime in the future, therefore the need for some versatility comes into the picture.
Here's the box getting mounted in its new home. I've got enough breakers supplied, so I'll remove what I'm not using to facilitate some extra breathing room.
Circuit breakers are intended to protect the electrical system downstream from them: the fixed wiring and devices. The input breaker to your panel really only protects the panel itself, which is just the bus bars. I'd just leave the 100A there as the input/main because you already have it (so it's free) and because it's less likely to be useful for some other purpose compared to the 30A breaker you also showed in the photo. It won't matter either way until some day when you want to be able to take full advantage of a more-than-30A hookup somewhere. In any case that breaker isn't intended to protect your supply cord; the breaker supplying the receptacle where your cord plugs in is responsible for that.
If you're planning to use both hot legs, make some effort to balance the actual loads (not merely the breaker capacities) so that there's about the same amount on each leg. At least consider the installed, regularly-used, and higher-power items like air conditioning, refrigerator, and heaters.
If you want to be able to use the traditional campground 30A hookup, keep in mind that it is single-pole (one hot leg). You'll need to plan to use just one pole in your panel, or use both poles but expect one to be dead when on a 30A hookup, or have some provision to jumper the two poles in your system together so they're both live off the same supply. If it were me, I'd run both poles separate out to the end of my power cord and get or make an adapter to connect both poles from my bus to the single pole available on a 30A hookup. (actually my plan is to limit my needs to 30A and not bother with the second pole)