shore power 110 or 220

110

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.

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/

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

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.

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.

Well, as someone who is electrically literate, I guess I'll have to pull out my meter next time I'm at a campground. I've always thought that a 50 Amp campground outlet is wired just like a home dryer outlet. The way 110/220 electricity works is that either hot side to neutral (which, although is tied to ground in the supply panel is NOT considered the same) yields 110 Volts while measuring across the two 'hot' terminals provides 220. The only difference is that with campers, the wiring does not allow for 220 Volt use, just two 110 volt circuit that divide the RV's load between the two 110 Volt feeds. If you look at the power lines into your house, you will see 2 'hot' leads, a neutral and a ground. The technical answer is that your hot leads are coming off each end of a center tapped transformer that provides 220 Volts across the two ends of the transformer wiring and either end to the center tap (which is neutral and also tied to ground) provides 110 Volts. To be properly wired, the outlet must have each hot terminal connected to opposite ends of the transformer wiring so to provide 220 across the two hot legs. Unless RV outlet posts have some odd circuit breaker mount, a 'twin' 220 Volt breaker will draw from the two different sides of the supply transformer.

1971duster340 wrote:
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.

I think you're confusing the 30 amp 120v cord with the 50 amp 240v one. It's the 30 amp cord that looks like the old 3 wire 240v dryer plug. Electricians have wired the supply for 240v, 2 hots, ground and no neutral. That will destroy a 30 amp rv since it's expecting 30 amp 120v, 1 hot, 1 neutral and 1 ground. The 50 amp supply is a 240v supply, not 120v as you said.

The fact that the 2 hots of a 50 amp connection feed different circuits in the RV is no different than what happens in your house. If you have a gas clothes dryer and stove it's likely the only 240v load would be central AC unit. Everything else is 120v running off one of the 2 hot legs. 240v is not confusing, it's better that people understand the differences between a 30 and 50 amp supply than to assume they're all the same. That's when problems happen.

Old-Biscuit wrote:
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

Timetoroll has it right.

Those that continue to say the 50amp spigot is 120 vac only should stop. They are wrong.

garyemunson wrote:
Well, as someone who is electrically literate, I guess I'll have to pull out my meter next time I'm at a campground. I've always thought that a 50 Amp campground outlet is wired just like a home dryer outlet. The way 110/220 electricity works is that either hot side to neutral (which, although is tied to ground in the supply panel is NOT considered the same) yields 110 Volts while measuring across the two 'hot' terminals provides 220. The only difference is that with campers, the wiring does not allow for 220 Volt use, just two 110 volt circuit that divide the RV's load between the two 110 Volt feeds. If you look at the power lines into your house, you will see 2 'hot' leads, a neutral and a ground. The technical answer is that your hot leads are coming off each end of a center tapped transformer that provides 220 Volts across the two ends of the transformer wiring and either end to the center tap (which is neutral and also tied to ground) provides 110 Volts. To be properly wired, the outlet must have each hot terminal connected to opposite ends of the transformer wiring so to provide 220 across the two hot legs. Unless RV outlet posts have some odd circuit breaker mount, a 'twin' 220 Volt breaker will draw from the two different sides of the supply transformer.

You're pretty much correct. There are some RV's with 240v dryers. The power lines coming into your house typically have 2 hots and a ground, no neutral. A true 240v load does not require a neutral, just 2 hot leads. Within your house the neutral load of one side (one hot lead) will cancel out the neutral load of the other hot lead at your service panel assuming loads are equal. When there is an imbalance, more load on one hot leg, the neutral load is carried back to transformer via the ground line.