Electricity that is…



First let me make it clear that I am NO EXPERT.  I know a little bit about a lot of stuff and I research for answers to what I need to know but don’t.  I am also not afraid to change my view based on new information.  By no means is this intended to be a comprehensive overview or guide.  I offer it as a starting point and an example of some things that work for us.  My knowledge of the subject continues to grow, so please do your own research too.  Comments are always welcome and appreciated.

You never know when a broken part or a loose wire, a wire that is too small for the load, or a creative bit of wiring is gonna sneak up on you and cause big problems.  Here is some information that will show you how to know the condition of the power pedestal before you plug your RV into it as well as things you can do to protect the systems on board after you plug in.

I found the following resource and believe it is the best and easiest to understand presentation of AC electrical systems relating to your RV that you will find on the net.  Les knows his stuff and if you take the time to read what he says you can gain a much better understanding of the subject too.  He is an RVer and has spent a lot of time compiling the information on his site.  On the subject of electrical systems and testing them, he has a way of making it all easy to understand and follow.  There were a number of others that contributed to the information contained on the site and while it is very technical, I feel like all of the information and examples are presented in a way that anyone can understand and make use of this valuable resource.

Here is a screen shot of his home page.


Here is a screen shot of the first page regarding Electric service, and the link to that page.


I particularly like this statement:

The RV owner should know the difference between the 30 and the 50-amp RV service also the other 30 and 50-amp Services that are used in everyday applications but could be harmful to the RV. Most importantly everyone should know how to test a receptacle BEFORE plugging in the first time.

You don’t have to be an electrical engineer or an electrician to understand this stuff and protect your RV and it’s systems. As we have all heard said, if I can do it, you can too.

I have also included some information on surge protectors so you can keep your RV protected after you have plugged in.

So here are a few of the highlights and why:

Test First

A simple tester can be made up which will show the condition of the pedestal before you plug in.  Why test, well there could be an open ground, a ‘false’ 50 amp wiring configuration or reverse polarity.  All of these conditions are things to be avoided and this tester will help you know if something is not right before you plug in.

30 amp tester


50 amp tester


Simple to make and for me a must have/must do before I plug in.

OK now how and why use the tester.

Test the pedestal first, again here is why, a good overview.  Notice the additional links on the left side of the page.  All great information and a terrific resource. If you read all of it you will gain a very good understanding of RV power issues and possibly how to avoid a problem.

You can do the basics or carry the testing further, here is how to test under a heavy load.  Here is the example given on an open neutral and the result of that condition.

We also have (keep) the plug in volt meter plugged into an outlet in the galley.  It’s easy to keep an eye on there and if we are connected to shore power, we glance at it from time to time.  If the wiring in the campground is out dated and not properly sized or inappropriate modifications have been made problems can occur.  Critical times would be when a heavy load is placed on the system, examples would be when a large number of air conditioners or electric heaters, crock pots, etc are being used.  Reason is that as load increases the potential for voltage drop also increases.  When voltage drops, amperage goes up.  That is where things get damaged and fires can be started.  The key is to shed loads when voltage drops.  Some newer RVs are being equipped with Electrical Management Systems (EMS) that ‘keep an eye’ on that stuff for you and automatically do what is needed.  For the rest of us, well it is the old self reliance thing.

Also be sure your power cord is firmly connected to the outlet.  Loose connections can cause a high current/overheated condition too.

Surge protection

After I test the pedestal, the next thing is to plug in the surge protector.  I would never hook up with out it.  Ours is a TRC 34750, there are newer models now but the basic function remains the same, protect against transient surges (or dips) in power.  (we also have a 30 amp unit)  You get what you pay for and the better units will also shut down if there is a high or low voltage condition.  There4 is also a delay in restart so your AC unit is not damaged from being turned back on should the unit interupt power.  I know of at least four times when our device was shut down and protected systems in the RV from damage.

A word to the wise is if you don’t have one, get one.  It is just a matter of time before a very expensive and bothersome surge will damage many if not all the circuit boards in your RV.  Today that is just about anything on board that uses power.  Water heater, converter/charger, refrigerator, TVs, microwave and more.

That is a start on the basics of AC electrical systems.  Do some research and know ‘before you go’.

Hope this helps.

50 amp Autoformer, there is also a 30 amp version