Chapter 3: Introduction to RV Electricity 120 Volts Alternating Current (AC)

Required statement:  Links in this chapter are to tools I have purchased via Amazon and I am an Amazon affiliate so I will make a small commission off of everything you purchase via my links, there is no extra cost to you.

Links to items are here:

Where does 120V AC come from?

Generator: There are on-board and portable generators, most people if they don’t have an on-board one look for a portable one.  When it comes to portable ones, there are two types of generators, noisy and less noisy.  You want to own and use a less noisy one, aka and Inverter Generator.  You do NOT want to own or use a generator that would be used at a work site, your fellow campers will HATE you for it.  There are multiple manufacturers out there who make inverter generators, most of them you can be standing next to the generator with someone else and be able to carry on a normal conversation.  My preference throughout the years have been the ones manufactured by Honda but do your research.

Inverter:  What is an inverter?  It takes battery power (Direct Current, which you can read about in Chapter 4), and makes 120 volts of Alternating Current (AC).  You can find all kinds, makes, models, modified/pure sine wave but the most important thing you need to know is what do you want to power and how many amps or watts does it pull?  You then will need the size inverter to handle that and most importantly the size of copper wire to hook to battery that can support the inverter.  Read more about inverters and other goodies in Chapter 9 Advanced Electricity.

Shore Power: You will hear this term; reality is it is a boating term but RVers have adapted it.  What is it?  It is where you plug into a campground or your sticks/bricks home, those are the two most common ones, aka commercial power.



You have a power converter in your RV, what exactly does it do?  It takes 120V AC and converts it to 12V DC to charge your battery and power your 12V DC items in the RV, normally also in that area is your 120V circuit breakers and the distribution point for all thing’s AC powered.  A typical converter looks like this:


Circuit Breakers

Just like in a house, your RV has circuit breakers to handle when you attempt to pull too many amps through a particular circuit, breakers are there to protect the wiring, so it does not overheat.  Your RV also has a whole “house” circuit breaker.  In a 30-amp RV you cannot pull more than 30 amps from the campground pedestal EVEN if you are using a “Dog-Bone” adapter to hook up to a 50-amp receptacle as you will trip the 30-amp circuit in your RV.  If you trip one, turn off the excessive electrical draw and reset the breaker.

Dog Bone Adapters

If you have a 50Amp RV, you need a female 50A -> male 30A adapter for those times when you are at a 30A ONLY electrical pedestal. Keep in mind you cannot run your entire 50A RV on a 30A pedestal receptacle, see Advanced Course on Electricity for explanation.

If you have a 30Amp RV, you need a female 30A —> male 50A adapter for those times when you are at a 50A ONLY electrical pedestal.

Ground Fault Circuit Interrupter

GFCI: These are those electrical sockets you see that have a reset button on them, usually near water sources, bathroom, kitchen, and outside electrical receptacles.  You will want to test them on a regular basis, using the test button on them.


Non-Contact Voltage Tester (NCVT)

What is a Non-Contact Voltage Tester (NCVT):  It is a device you can use to detect electricity without using a multi/volt-meter.  Why would you want to do that?  As you will see below during a Hot Skin Condition (in Chapter 15) you can check the outside of your RV for stray electricity without having to have to plug in probes from a voltmeter.  It is a very simple tool to use for newbies and fits perfectly for the audience of this book. You can find the one I use here:  NCVT:, it is a Southwire model 40136N.

Checking of Campground Pedestal (Basic)

Test Non-Contact Voltage Tester (NCVT) in a working electrical socket, before using at pedestal, based on instructions in the manual for your specific NCVT. The one I have is a Southwire Model 40136N.

Get out your NCVT and turn it on, most of them should beep.

Walk up to the pedestal, WITHOUT TOUCHING THE BOX WITH YOUR BARE HAND, touch the outside of the electrical box with the tip of the NCVT, then all around it, just lightly touch the box, do not tap it hard as you could get a false positive reading.

Did it beep, not just once while holding it there but continuous beeping?

If so, STOP DO NOTHING ELSE, DO NOT TOUCH THE BOX WITH YOUR BARE HANDS. Contact the campground admin/owner and let them know the electrical pedestal has stray voltage on the outside of the electrical box.

If no beeping from touching all around the box, then you can continue, at this point, it means one of two things:

There is no stray electricity on the box OR

The breaker in the box is turned off.

If you got here, then it is time to open the box and see if there is a circuit breaker in the box, not all electrical pedestals at all campgrounds have the breakers in the electrical box.  Open the box.  Keep in mind as you move along you will want to know which breaker to turn on, 50 amp (larger 5th wheel and Class A), 30 amp (usually travel trailer and Class C), or 20/15 amp (mostly the popup type RVs).

Is the breaker turned on or is there no breaker?

  1. If breaker is present and it was turned off then while not touching the metal box, turn it on and do the test again with the NCVT, if no beeping, turn it back off and plug in your RV and turn breaker on.

  2. If breaker is present and it is turned on, then you are safe there is no stray electricity on the outside of the electrical pedestal box, turn off the breaker and plug in your RV and turn breaker back on.

  3. If no breaker, then it is somewhere else possibly in a central location at the campground but at this point you are safe to plug in your RV.

Ideally it is best for option #1 above, so you don’t have to plug into a live electrical socket.

If you want to do more thorough testing, like checking voltage/hertz, polarity, that can be found in Chapter 9:  Electricity Advanced.