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Arnoldjeff · 08-06-2014, 07:20 PM

Hi everyone – my 2014 19 foot flying cloud has a 30 amp connection on it for electrical hookup. What if a campground only offers 50 amp service?
Do I need some kind of adapter?

Thanks!

Al and Missy · 08-06-2014, 07:33 PM

As I understand it, the answer is maybe, but probably not. The 50 amp connector is different, but the only campground I asked about it said their box had both connectors so, in effect, they have both 30 amp and 50 amp service. Some campgrounds or campsites may only have the 50 amp connector and for those you would need an adapter.

egraham · 08-06-2014, 07:43 PM

You need to keep a 50 to 30 amp connected on your trailer.
I also keep a 30 to 15

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acstokes · 08-06-2014, 07:45 PM

You need what's called a dogbone adapter. Something like this:

http://www.amazon.com/Camco-55175-Po...50+amp+adapter

Rich W · 08-06-2014, 07:55 PM

The 30-amp plugs get a lot of use. Sometimes you get a better connection using the 50-amp with the dogbone connector acstokes has a link to. Like egraham I have 30 to 15-amp connector as well. You just can't have too many adapters. You never know what you're going to come across and it's better to have one handy.

You should also look into getting a smart surge protector (like Progressive Industries) so you can check the campground connection before plugging in your AS. It checks for correct polarity, open grounds and the like. Here's what I have (there are others)
SSP-30

Foiled Again · 08-06-2014, 08:01 PM

Truth is it's rare to find a post that doesn't have both - and when it's only one, it's almost always a 30 amp service. I keep a 50 to 30 dogbone simply because it's not uncommon for the 30 amp receptacle to be worn out. I've had connections so loose that I've had to bungee the cord to the post... and that's not a solid connection. Could even be dangerous with a little arcing and sparking. Of course if I were more methodical I wouldn't do anything to unhitch until I'd hooked up the electrical service and tested it. Always happens that I've already unhitched and then just say "OH, naughty word!".

A dogbone is a handy thing to have.

Paula

Cannonball · 08-06-2014, 08:37 PM

Many state parks may offer only 30A service. The adapters are inexpensive. Just carry them in case of need.

Cannonball, Deep in the Heart of Texas!

WBCCI #4387, Air #84080

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cwf · 08-06-2014, 08:47 PM

If you plug in with little or no "resistance" chances are the 30 amp receptacle is shot.

Last trip to a Corps of Engineer park we noticed the problem and called the front desk to report the 50 amp was out. They fixed it within 45 minutes and were really nice folks with good manners and grooming.... Not your "usual" experience at some places.

Always check the voltage when you are running with an electrical load. The smarter (more expensive) surge and power protectors will test, warn and may even protect should power be bad. But they can't "fix" bad power.

There are "line conditioners" which can handle whatever your wallet can tolerate in protection.

Anyway, simply keep up with condition of your hardware, look for discolored or damaged lugs on the plugs... You will see the problems sooner.

GeocamperAS · 08-06-2014, 08:53 PM

Correct me if I'm wrong. If the AS has a 30amp cord it is rated for 30amps. If the camp post only has a 50amp and a 15amp it would be better to use the 15amp. Here is my logic, if I use the 50 to 30amp adapter I would not trip the 50amp breaker unless I was to draw 50amps or more. However my 30amp cord will over heat if I draw more than 30amps.

Cannonball · 08-06-2014, 09:49 PM

I am not a electrician, but my understanding is as follows: a 30 A service has three legs (prongs) on the plug. A 50 A service, in order to get to 50 A, has four legs on the plug. All the adapter does is allow you to plug into the plug. If you use a 50 A adapter on a 30 A cord, you will only get 30 A. The adapter just kills one of the legs from the actual 50 A service. Your Airstream will not get more than 30 A, unless there is some other major electrical problem with the service being provided by the campground.

Cannonball, Deep in the Heart of Texas!

WBCCI #4387, Air #84080

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cwf · 08-06-2014, 09:54 PM

It gets far more interesting!

I upgraded 30 to 50.

Running 30 we could not run AC, water heater and hair dryer or microwave.

With 50 I run both AC and all 110 appliances, just like home.

The "dogbones" merely allow you to plug in. You MUST self manage power use.

acstokes · 08-07-2014, 06:05 AM

Quote:

Correct me if I'm wrong. If the AS has a 30amp cord it is rated for 30amps. If the camp post only has a 50amp and a 15amp it would be better to use the 15amp. Here is my logic, if I use the 50 to 30amp adapter I would not trip the 50amp breaker unless I was to draw 50amps or more. However my 30amp cord will over heat if I draw more than 30amps.

In this instance one of your AS breakers would trip. If you connect to the 15 amp you can only draw 15 amps before a breaker would trip so you won't be able to use your AC, microwave, toaster, or coffee pot.

AnnArborBob · 08-07-2014, 06:39 AM

Cannonball's post is correct. If you use the 50 to 30 amp adapter, your electrical service is only going to provide 30 amps of power so you will not be able to run the second AC, you will not "overheat" your 30 amp cord, you will not "fry" your on-board electrical system and you will not trip the campground breaker for making the hookup this way. The 50 to 30 amp adapter effectively disables one of the legs on the 50 amp service and creates a 30 amp service for you.

TG Twinkie · 08-07-2014, 07:06 AM

The 50 amp service provides 50 amps of current to each leg. Since you are using 1 leg, there is still 50 amp capacity. Even when you plug in the adaptor. It doesn't know the difference between your rig and one that has 50amp requirement.
You should have a main 30 amp breaker in your coach. Which will trip if overloaded. The only part that is not protected is the shore power cable. If it were damaged to the point of causing the camp sight breaker to trip. It would not matter if it were 30 or 50 amp.

AnnArborBob · 08-07-2014, 07:17 AM

With all due respect to TG Twinkie above, a licensed electrician once explained to me that a properly configured 50 amp service has four leads, two positives, a neutral and a ground. A 30 amp service has only one positive, one neutral and one ground. Despite the arithmetic suggestion otherwise, a 50 amp service is really two 30 amp services in parallel. The 50 to 30 amp adapter we are discussing (i.e., the dogbone) has a dead termination for one of the positive leads in the part that connects to the RV park's 50 amp plug, therefore the current that is flowing through your 30 amp wire is really only 30 amps. If the breaker trips in your trailer after hooking up to a 50 amp service with the dogbone adapter, it's not because you are getting 50 amps, there is something else terribly wrong that would be going on.

GeocamperAS · 08-07-2014, 08:04 AM

A 30amp RV setup uses one hot (L1), one neutral (N), and one ground (G). It is fused (breaker) only on L1 with a 30 amp breaker. Voltage between L1 and N is 120vac.
The 50amp RV setup uses two hot (L1) and (L2), one neutral (N), and one ground (G). It is fused (breaker) on L1 and L2 with a 50 amp breaker on each of L1 and L2. Voltage between L1 and N is 120vac and between L2 and N is 120vac and between L1 and L2 is 240vac.
Being that most RV's only use 120vac, if yours has a 50amp plug, have of your loads (electrical items in your RV) will use the L1 to N side at 120vac and the other half will use the L2 to N side at 120vac. Each protected by its own 50amp breaker.
The 50 to 30amp adaptor uses only one of the L1 or L2 legs. However it still has the 50amp breaker at the pedestal. So your 30amp power cord could have more than 30 amps running through it if you don't have a 30amp main in your trailer.

GeocamperAS · 08-07-2014, 08:25 AM

Let me add the the above post by explaining amperage.
Your breaker panel has one main breaker rated at 30 amps and 3 branch circuits rated at 20 amps each.
Branch circuit 1 protects the A/C.
Branch circuit 2 protects the microwave.
Branch circuit 3 protects all the outlets.
You turn on the A/C which draws 12 amps. Well below its 20 amp breaker.
You then turn on the microwave which draws another 12 amps. Well below its 20 amp breaker.
However 12 plus 12 equals 24 amps which is now flowing through the main 30 amp breaker.
You now turn on a blow dryer (which I would never use due to lack of hair the past 10 or so years) which draws 8 amps. Well below the 20 amp breaker it is on.
However 12 plus 12 plus 8 equals 32 amps. The main will trip.
Now if you don't have a main in your trailer and you are using a 30 amp cord pluged into a 50 amp service with an adaptor, your cord will over heat.

aftermath · 08-07-2014, 09:01 AM

This is a very informative thread. Thanks Geocamper for the accurate explanations. You were right on when you explained that current is not the same as voltage. Here is the way I see it.

When you use an adapter and plug into a 50 amp service your trailer "can" draw more than 30 amps. I have one AC and no microwave. We don't use many appliances and when the wife wants to dry her hair we are not running the AC so I am not worried.

If I was powering up a bunch of things, once the current went above 30 the main breaker in the trailer would trip. So, to answer the OP's question, you can't damage your trailer when you hook up to the 50 amp post. You could damage your power cord and that would be the worst of it but I think that this would be a very long shot as well.

AnnArborBob · 08-07-2014, 10:12 AM

Good explanations and clarifications, thanks!

TG Twinkie · 08-07-2014, 10:57 AM

With all due respect. Just because an electrician has a license. It does not mean he/she is knowledgeable in all aspects of an electrical system.
I am glad others chimed in her to add to my explanation of how the power system works when it comes to 120/240 volt 4 wire systems and how that system is wired to an RV.
In most RV systems only one hot leg is required. However there are a number of the large motorhomes and 5th wheel trailers that use both legs of the 240 volt 4 wire system. These units are equipped with multiple air conditioners as well as microwaves and washer and dryer combos etc.
An example of a 30 amp 4 wire system in your home would be the circuit that provides power to the electric dryer. The 240 volt circuit L1 & L2 power the heating element. The motor a controls are 120 volt using one leg and the neutral.
The electric range requires a 50 amp 4 wire system. The oven elements are 240 volt in most cases while the stove top elements and controls are 120 volt.