Originally Posted by InsideOut
We found them
at Home Depot - not the same brand as the originals, but the same function and they fit. The side flange lets you rivet to a rib.
That's a "New Work" box. The side flange is to anchor to studs or, as you said, ribs. Great if you have the skin off. Considering the way that Airstream installs outlets, that's a lot more trouble than it's worth.
I use an "Old Work" box
, also from Home Depot. (After taking one of the New Work boxes back.) Just cut the hole large enough for the box to slide in and the flanges at the top and bottom give you places for four screws to attach it to the inner skin. Much easier.
Once you have these in place, you can use normal outlets and switches instead of the special RV ones that have the faceplate made on and those strange "wings" to hold them in the hole.