The power poles (trees) in most campgrounds contain 2 or 3 outlets, a 50amp, 30amp and maybe a 15amp. Get yourself a heavy duty (12 or 10 gauge wire) extension cord, not longer than 50 feet.
Keep your rig plugged into the 30 amp outlet then plug the extension cord into the 15 amp outlet, if there is one. If not, most RV stores sell 50amp to 15amp adapters. Slip the other end of the extension cord into your rig, possibly through the seal of the slide, and plug the heater into that.
You'll keep the RV electrical system intact and at it's 30 amp capacity and still have an additional 15amps for your heater, or extra fridge during the summer.
Depending on how often you'll be using that "circuit", you may want to "hard wire" it into your rig. Mount a shallow electrical box on a wall that won't interfere with the slide, drill a 1/2" hole through the floor and into the "basement". Cut the "female" end off the extension cord and feed that up through the floor and into the electrical box. Strip the wires on the end (I usually "tin" stranded wire) wire it to a duplex outlet, screw the outlet to the box and add the cover.
In the basement, coil the extension cord to keep it neat, use a little silicon to seal the hole you drilled and close the door. When you're ready to use it, open the door, pull out the extension cord and plug it into the power pole. Lower the door (you can slide a piece of hose over the cord to prevent damage) against the cord and you're good to go.
Have a good one,
Hey! How's that "HOPE & CHANGE" working out for you?
January 20, 2013 - The end of an ERROR!