shore power 110 or 220

240V or 220V should be banned in most RV power supply discussions...it's confusing. Just because the receptacle in the shore power pedestal looks like your dryer socket, the electricity accomplishes different supply once it enters the dryer vs. your RV.
Think of your RV supply as having 2 seperate 120V wires that supply different portions of the RV, front half and back half in simple terms. While most 50A breakers are tied, if you could switch only one off, half your RV would loose power, but a dryer would only get half the voltage necessary to operate...bad news!
Electricians have wired a 120V, 50A RV receptacle incorrectly because it looks like that other, larger voltage supply they are familiar with...again, bad news.
Forgot to mention, the cable is fatter because it has 4 #8-#10 wires vs. 3 #10-#12 wires.

To put it another way, both are at the pedestal;
50A with 110/220V available at the receptacle. (Note that this is a standard 50A recept for a common 240V residential range.) That full 240Volts is brought up to the braker panel in the RV where it is separated into two 120V busses for use in the RV.

30A receptacle with 120V is also Available at the pedestal.

CG power pedestals have 120V AC whether it is a 50A 4 prong receptacle, a 30A 3 prong receptacle or the 20/15A regular house outlet.

ALL 120V AC

For RV use:
50A has TWO 120V AC HOT lines, ONE neutral, One ground
30A has ONE 10V AC HOT line, One neutral, one ground
20/15A same as 30A --One HOT, One neutral, one ground

luberhill wrote:
I see the heavy cords and plugs for the class C's so is power at campgrounds 110 or 220?

There is heavy and heavier.

3 prong is 30 amp 120 volt NEMA TT-30 and 3,600 watts
4 prong is 50 amp 120/240 volt NEMA 14-50 and 12,000 watts

You can use an adapter to plug either RV into either supply.

http://www.myrv.us/electric/

Most class c use a 30 amp 120 volt plug. Larger motor homes and fifth wheels use a 50 amp 240 v plug. There's no chance of interchanging.

110