This article is about using a 50 amp to 30 amp adapter when you have a 30 amp RV.
In a previous blog post I discussed the possibility of needing to adapt a 30 amp campground service to a 50 amp RV. This is a very common scenario in many campgrounds.
But a less common scenario is just the opposite. And that’s when you need to run a 30 amp RV from a 50 amp campground pedestal.
So can you use a 50 amp to 30 amp adapter safely in this case? Let’s see!
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Why Is An Adapter Needed?
There are a lot of RVs on the road that are wired for a 30 amp electrical service. That rating describes the current the service is designed to handle.
A 50 amp service has more capacity, but your RV draws current according to the appliances and equipment you use. The bigger outlet does not force 50 amps into your RV.
The difference between a 30 amp and a 50 amp RV service becomes especially apparent when using air conditioners. A 30 amp service will usually only allow the operation of one AC unit in the RV.
But a 50 amp service can run more than one AC unit and even provide plenty of extra power at the same time. Why? Let’s take a look at a very useful electrical formula to understand why 50 amp RVs can do that.
A Useful Electrical Formula
At a correctly wired RV pedestal, each hot line supplies about 120 volts to neutral. A 30 amp hookup has one hot line, while a 50 amp hookup has two.
A handy way to compare these RV service ratings is to multiply volts by amps. That gives us the familiar wattage figures below.
So if we multiply 30 amps times 120 volts, a 30 amp RV can consume 3600 watts of power at one time. But a 50 amp RV has two legs of service going into the rig instead of just one.
For a 50 amp RV service, multiply 120 volts times 50 amps for each of the two hot lines. That gives a total rated capacity of 12,000 watts.
Clearly then, a 50 amp RV service has more capacity than a 30 amp service. So what happens if you use a 50 amp to 30 amp adapter for your 30 amp RV?
How Does A 50 Amp To 30 Amp Adapter Work?
Your 30 amp RV still has a 30 amp limit when connected to a 50 amp pedestal.
An ordinary adapter changes the plug connections. It does not step down voltage, regulate current, or provide overload protection.
Properly rated circuit breakers at the power source and in the RV protect their respective circuits against overloads. The adapter does not replace those breakers.
Click on the link below to find out more about 50 to 30 amp adapters like this one.
Click here for a 50 amp to 30 amp RV plug adapter
(This is an affiliate link for the product on Amazon. It does not cost you any extra to buy the product using my affiliate link if you choose to do so)
A 30 Amp Plug In A 50 Amp Adapter
As mentioned above, a 50 amp RV outlet has two lines of power instead of just one. And the 30 amp RV plug only uses one line of 120 volt power.
The correct 50 amp male to 30 amp female RV adapter uses one hot line, neutral and ground. The other hot line is left unused, so the RV still receives 120 volts.
The pedestal’s circuit breaker is still rated for the 50 amp supply. It does not become a 30 amp breaker when you add an adapter.
Your RV’s 30 amp main breaker provides overload protection for the RV. Keep your total use within that 30 amp limit and each branch circuit’s rating.
Use correctly rated equipment and follow your RV, adapter and EMS manufacturers’ instructions. If your RV manufacturer prohibits this hookup, don’t use it.
So use a 50 amp to 30 amp RV adapter only when your equipment allows that connection, and keep the required circuit protection in place.
Additional Protection From An EMS
An EMS can add protection against certain voltage and wiring problems.
Some RVers add a 30 amp RV surge protector that is an EMS (electrical management system) for these extra protections.
The protections depend on the model, so check its manual. Don’t assume that a 30 amp EMS will shut off power whenever current exceeds 30 amps.
For example, the Progressive Industries EMS-PT30X monitors high and low voltage and certain wiring faults. Its instructions identify the power source and RV circuit protection as the current-limiting devices.
Click here to view a 30 amp surge protector EMS
Whether or not you add an EMS, the RV still needs its required circuit protection and properly maintained wiring.
What does All Of This Mean For Your 30 Amp RV?
So what does this mean in terms of what you usually do with your RV? Does this adapter change the way you use your appliances or devices? Not really.
With a manufacturer-permitted connection and a suitable power source, your RV still has its original 30 amp limit. Keep using your appliances within that limit.
On the other hand, RVs with a 50 amp service that plug into a 30 amp receptacle will have to manage their power usage. Otherwise, they can overload the 30 amp supply and trip its breaker.
So a 50 amp pedestal does not turn your 30 amp RV into a 50 amp RV. The adapter changes the connection, while your RV keeps its original limits.
I hope this helps you understand how RV electrical services work and how adapters help in special situations. Let us know if you have had any interesting experiences with 50 amp to 30 amp adapters in the comments below.
Have safe and happy travels my friends!
That was an excellent presentation!
I have discovered my 30 amp camper performs
Better when I plug in a 50 amp to 30 amp converter.
Then plug into the camper.
I get pure 30 amps into the camper and my electric items
Will all work at the same time.
Example: AC, hot water heater and coffee pot all
Running.
When using straight 30 amp from pedestal I had to turn something off to run coffee pot.
That’s an interesting idea Richard. I’m glad it’s working for you. Thanks for mentioning that. It might be something that benefits others having the same issues.
Thanks for the explanation. I am using this tip right now in a time of need—as our 30A connection has failed — and this explanation is really reassuring. It makes sense when you think about it, but it certainly is nice to be hear it from someone with expertise. So far this has been more consistent, and with really cold temps and using electric heaters as much as possible, we are putting a strain on our capacity. So thank you.
i don’t think you get 50 amps on both legs of a 50 amp service. i think you get 20 amps on one leg and 30 amps on the other. I mean if you had 50 amps on both legs why would you need two legs to power a 50 amp trailer? And if you were providing 50 amps on both you would have a 100 amp service. and the bit about doubling the voltage to 240 volts. misleading because nothing in the rv runs on 240 volts. I will give you the 3600 watts for 30 amp service. but adding 20 more amps should only give you 2400 watts more. You doubled your amps and quadrupled your power?
Actually Craig, my article is correct. I know that it may be a little difficult to understand, but there are indeed two lines of 50 amps coming into the RV at the same time. Both are operating on 120 volts. So, one leg is capable of handling 6000 watts of power (50 amps X 120 volts) and the other leg is capable of doing the same. That means that a 50 amp RV service can provide up to 12,000 watts of simultaneous power to the rig. Here is a link to an RV electrical expert who explains the whole matter in even greater detail – https://www.rvtravel.com/rv-electricity-power-principals-50-amp-shore-power/
Thank you for information.. my initial rig was 50 amp with 2 AC’s. 2nd TT is only 30 amp, struggling to adjust, tripping breakers, and today lost power and found adapter to trailer plugs burnt bad. I had no idea that available wattage was such a vast difference between 50 to 30 amp. So important to know these things when buying an RV – just because there’s electrical sockets and appliances throughout the RV – Does not mean they can be pulling power at the same time !!!
Hi Pam. Thanks for adding your personal experience to the discussion on this subject. I’m sure it will be helpful others!
Thank you for a very informative article. I am just getting interested in the RV lifestyle and I hope to indulge myself when I retire in a couple of years. In the meantime I am trying to do as much research as I can to learn. This article is very well written and easy to understand for a newbie.
Thanks again.
Hi Steve. I’m so happy that the article was helpful. A lot of RVers have questions about electrical issues. And you are doing exactly what you need to do by getting as much information in advance as possible. It will shorten your learning curve dramatically when you actually start RVing. I wish you fun adventures and happy travels on the road ahead!
Excellent Info…thanks for confirming what I thought to be the case and assuring my usage of the power options.
I’m glad you enjoyed the article. Have safe and happy travels!
Excellent and Simple to understand!!! Thank you!
I build houses for a living and understand a lot about electricity. But I am a new, first time, RV Camper owner and don’t know a lot about camper wiring. I like to remind myself that “I don’t know what I don’t know” and thought I would look up some info and came across your article. You explained this and gave additional information that made me feel completely confident when done reading. Thanks!
Hi Ron. Thanks for leaving some positive feedback on this article. It’s much appreciated and I’m glad that you found the information helpful!