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RV systems-What you need to Know | RV Safety Tips and Tricks
RV Electrical Systems-What you need to Know

RV Electrical Systems-What you need to Know


On our most recent trip, to our favorite spot, it became abundantly clear to me that I really didn’t know enough about our RV’s systems, the electrical system in particular.  And, of course, the next question was, “Do others know enough about the systems in their RV?”

Now, by asking that question, I’m not saying we are all dysfunctional when it comes to the systems in our RV’s.  We are humans after all and we certainly don’t all know it ALL.  If we don’t we will, at some point, be quite frustrated when an issue comes up, (and it will come up), and we can’t figure it out. 

After all, we purchased our Trailers/RV/Motorhome in order to have the freedom to go places we wouldn’t normally be able to go, to make memories with our families, and friends and enjoy the fresh air and beauty of nature and all it has to offer.  

Whether we are going to our favorite spot to just have a time of relaxation or we have an extended trip to tour a specific area, our trailers are all we’ve got and we don’t want any issues cropping up to spoil our adventures.  If issues DO arise it would be great if we could figure out how to fix them ourselves and save ourselves $$$ in the process 

I’m telling you this because the last trip we took last year was nothing less than just that, frustrating.  It started even before we left when I tried to hook up our 2 batteries in parallel, the way I had already done, (correctly I thought).  I had done it right before so, why would this be any different?

Like I said, I thought I had my batteries put together the right way, (I didn’t have a drawing or a picture of how it was supposed to go together, duh!),  but nothing was working.

So I went on youtube, found a video from the actual company that made our trailer.  Again, I had thought I followed it step by step but when putting one of the wires on to connect the batteries in parallel, there was a major spark which blew out a couple of 40-watt fuses and, I think, an important breaker switch.

It was on the 4th day when I was writing some notes about this in a journal, that I thought about checking the fuses. That’s when I discovered I had blown the 2-40-watt fuses.  I found some replacements a few days into our trip but that still didn’t fix all our issues.   

Long story short, a few days away to relax and enjoy were anything but and in spite of being able to fix some of the issues.  Our trailer was still going to be paying a visit to our RV service center, CHA-CHING$$.

Thank goodness we have extended warranty insurance which actually did cover some of the cost to fix things.

I found out that I don’t know anything about RV electrical systems.  Just off the top of my head, what have I learned so far?  This is what I came up with.


FIRST AND FOREMOST – Most of us purchase our RVs new from a dealer.  With the batteries in mind, the first thing you should do is draw or take a picture of the way the wires are connected to the batteries.  Before you disconnect the batteries of your trailer/RV/Motorhome, turn off all the breaker switches on the electrical panel.  This will ensure that they will ALL be safe from power surges.  

When the time comes to reconnect the wires to the terminals of your RV batteries check the photo/picture that you have to make sure everything is connected properly.

Our service technician showed us another way to do this.   He did this by numbering the battery posts and then numbering the wires that attach to each post.  Any wire that is attached to the #1 post also gets the wires marked #1 and any wire that is attached to #2 post gets the wires marked #2 and so on. 

The best time to do this is when you bring your NEW trailer/RV/Motorhome home and before you disconnect ANYTHING for the first time.  Or even better, have the service technician number them for you before you leave the place where you bought the RV.

2 – Get Yourself a Multi-tester and learn how to use it properly.  They really are quite simple to use. Read the instructions and, with a little practice, you will be able to tell if the power systems in our trailer are working properly and if your batteries are properly charged.

3 – Check your RV’s power system often and, at least, 5-7 days prior to leaving on a trip. Check everything; lights, fridge, stereo, TV, Microwave, heater, plugs (inside and out), and exterior lights. If there are any issues, you will still have time to have them fixed before you leave.

4 – Always carry a 25-50 foot,  extension cord and make sure it’s at least 14 gauge. 16 gauge is not heavy enough to handle the amount of power required for an appliance, like a refrigerator, if needed in an emergency.  Most RV parks won’t allow the use of a lighter extension cord so having one that is at least 14 gauge is a good idea.  

We had an incident where our fridge stopped working and we had to hook it up to a 20 AMP power source with a borrowed 50-foot extension cord.  This did the trick and two days later we were able to solve the issue, ( a blown 40-AMP fuse).

5 – Some of your RV plug sockets work on the GFI switch. This switch is usually found in the bathroom and controls any plug that is near a water source.  These include plugs in the bathroom, around the kitchen sink, and the outside plugs.

6 – Make sure you have extra fuses, of every size, in your Trailer/RV/Motorhome.  Even if you never blow one you will be secure in the knowledge that if it does happen, you’ll have it covered.


These are some of the things I thought about just off the top of my head but then I thought, “There has to be more”. NO, I knew there was more and, I needed to know, so the next step was to do some research and learn some basics, and tips, about electricity and how it applies to the RV lifestyle.

The first thing I learned, (and I already knew this), was that our RV’s/Trailer/Motorhome work on campsite-electric-hook-upeither a 30-amp or 50-amp system.  If your RV has a three-pronged large plug, (middle plug), it works on a 30-amp system and If it has a four-pronged large plug, (left plug), it works on a 50-amp system.  30-amp is most commonly used in travel trailers with larger ones with more gizmos like fireplaces and TVs, (like a 28+ foot Denali), will be equipped with 50-amp.  Newer Fifth-wheels and Motorhomes also come equipped with 50-amp power systems also because of the extra gizmos and accessories that they carry.

Here is an example of what a campsite power panel would look like.  I found several images of many different campsite panels, this one is pretty standard and looks like the one we were using at our camp site.

If you have a 3-pronged system you probably have a travel trailer and you will be able to your Air Conditioner and your microwave and maybe another, taking into consideration that the ones that produce heat;  like hair dryers, toasters, and kettles, will use more amps.

If you have a 4-pronged system you probably have a larger travel trailer, Fifth-wheel or a Motorhome and can use just about anything you want.  You probably won’t be using all your appliances at the same time but, on the off-chance that you do, you could still throw a breaker switch.  We just have to be careful not to go over the max power draw for your specific unit.

How Much Power Does My Gizmo/Appliance Draw?

Let’s stop here for a bit and take a look at what or how much power is required by the different electronic devices in our RV/Trailer/Motorhome.

First things first. not all of the electrical components, we use in our RV, run on the same power. Some things like the microwave, the plugs, TV, Radio/DVD/CD player, Air Conditioner, and the fridge (when it’s in electric mode), all run on 120-volt power.

The other stuff, like the awning, water pump, slider, range-hood fan, overhead and outdoor lights, the little bathroom fan, LP Gas leak detector and the refrigerator (when in LP Gas mode), all run on the 12-volt system.

Now, in the power distribution box, there are 2 sides, (at least this is the way it is in my trailer).  In my trailer, the left side of the box contains all the BREAKER switches and two 40-amp fuses.  This is the 120-volt side of things.

The right side has a bank of 15 amp fuses, as well as a row of red, LED indicators, to warn me when one of them (the 15-amp fuses) blows.  These fuses are for the 12-volt system.  The 40-amp fuses don’t have the LED indicator so, if something stops working, check the 15-amp LED lights, then the breaker switches and then the 40-amp fuses.

Like I said earlier when the thought occurred to me, I checked the 40’s and found them both gone and replaced them as soon as I could.

Make sure that all the switches and fuses are properly labeled as well.  If something isn’t working it will be easier to locate.

NOTE:  If you aren’t plugged into an outside power source, as long as your battery/s are charged, you can still use the 12-volt system if you have 12-volt deep cycle battery/s in your RV, you just won’t be able to use things like the microwave, air conditioner, plugs, or the fridge when it is in electric mode and you will have to have a way to recharge those batteries when they get too low to support the equipment you are running.

For a motorhome/coach, it’s different.  there will be an auxiliary battery/s for the Coach system, (12-volt), and a battery for the automotive system, (starts the engine and runs the exterior lights and dash lights).  The battery for the Coach is charged when the motor is running, just like in your car or when the generator, if you have one, is running or when the coach is plugged into a land power source.


How Much Power Does My STUFF Use?

How do we know how much power it takes to run an appliance or other electronic devices we use in our RV/Trailer/Motorhome.   Well, some appliances will tell you, on a sticker, how much they use and some electrical devices won’t.  Some operator’s manuals will give you a list of items along with a number of AMPS they draw.  Here is a partial list of some of the most commonly used electrical items in RV’s today:

  • TV – 1.5 amps 
  • Refridgerator – 2.5 amps
  • Toaster – 8-10 amps
  • Hair Drier – 9-12 amps
  • Coffee Maker – 8.3 amps
  • Roof Top AC – 13.5 amps
  • Power Converter – 8 amps
  • Microwave – 13 amps
  • VCR – 2 amps

We now know a little more about our power systems and how much power certain items use in our RV”s and how many of those things we can use at the same time without blowing something.

HERE’S A TIP:  When you’ve finished your trip and your RV is parked it has been suggested that you turn off all your breaker switches, including the ones at the campsite power source.  Make sure all your appliances are off as well.  It only takes a couple of minutes and ensures that everything will be safe if there is a power surge when plugging into a power source or when connecting up your RV’s battery/s.



You own a Motorhome and have just arrived at a campsite that only provides 30-amp 3-prong power.  Your Motorhome has a 50-amp 4-pronged plug.  You can use the 30-amp power but you will need an adaptor in order to plug into the power source.  You can purchase these at your local RV dealer or through, (see below). There are a few different kinds and I would recommend the one with the handle.  It’s a little more expensive but the handle makes it easier to50-amp-to-30-amp-adapter-1 plug and unplug from the power source.  You won’t be able to use as many devices or appliances but at least you will have power for the important stuff.


rv-electrical-adaptors-30-amp-to-20-ampIn a Travel Trailer, the same thing applies,  You may only have a 20-amp or 50-amp service to hook up to but you do have an adaptor that came with the trailer, (see left).  Just put that on the end of your trailer plug and into the three prong outlet and you’re good to go.  

Again, you won’t be able to use anything extra at the same time but you will have the essentials.  You will be able to use the50-amp-to-30-amp-adapter-google-search-google-chrome-2016-10-25-16-12-34 microwave OR the air conditioner OR a couple of other devices with low amp draw but not all at the same time.  If there is 50-amp service available a 30-amp to 50-amp is also available at (black adapter),


These are just a few of the things we need to know about our RV electrical systems.  I hope this has been helpful.  I will be putting out more info on this subject in the near future including information on inverters and converters and info on batteries.

In the meantime, we are all in this together and I hope you all have a great camping experience and as always….if you have any questions or comments or if you have any stories of your own, please leave your question or comment in the space below and I will get back to you as soon as I can.

This is Wayne wishing you Happy Camping and DRIVE SAFE.

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