Written by 6:33 pm Buy an RV, Rv Stuff

RV Electric 101

Understanding Your RVs Electrical Systems

Having electric in your RV almost feels decadent. After all, many people call this camping but really, it’s like having a house – but on wheels. The ability to run a microwave, hair dryer, TV, toaster, espresso machine – even a washer/dryer – is brought to us by the magic of “shore power” (usually) or a 12-volt system with an inverter. In this article we’ll discuss electric derived from the post and plug.

Amps Draw

It’s important to note that in an RV you can’t run several appliances at once or you’ll blow your breaker. Here’s the skinny. Your RV has either 30 amp or 50 amp capability. Amperage is the amount of power available to use. Each appliance pulls a specific number of amps. Exceed 30 or 50 amps (depending on your rig’s system) and poof – the power overloads and the breaker trips. Here’s a handy list of some of the typical appliances and the approximate amps required to operate them:

Microwave 12.8 amps
Air Conditioner – 15,000 BTU 12.5 amps
Electric Water Heater – 6 gallon 12.5 amps
Toaster 10 amps
Hair Dryer 10 amps
Electric Frying Pan 10 amps
Electric Coffee Pot 10 amps
TV 2 amps
Crock Pot 1.5 amps
Heating Pad .5 amps

Most electrical products note how many watts or amps it takes to operate them. If you only see watts divide the watts by 120 (volts) and you’ll have the amps. Reverse that – multiply amps by 120 (volts) and you’ll have the watts.

Volts Flow

While amperage is the draw, voltage is the flow. Think of voltage as a river. If you’re canoeing down a dammed river you have to paddle a little harder to move along. If the river is free-flowing you don’t have to work as hard to get downstream. Acceptable voltage (at 110 to 127 with no load on the system) allows your appliances to run in an efficient and easy manner. Drop below 110 and your appliances must work harder, get hotter and suffer the possibility of failure. For instance, never operate your A/C when your voltage is below 106 (when it’s running) or you risk damaging the motor – a costly repair (or replacement).

How do you know the volts flowing into your RV? Simple – test it. I might go a bit overboard but I hate the thought of an improperly wired or inadequately powered electric connection zapping my system. This is the very first thing I do when I arrive at a site in case the power’s unacceptable and I have to move. To start with, I use a polarity tester (a little plug with red and amber lights and a key telling me what combination of lights should or should not light up) to make sure the power is wired correctly. Next I use a digital volt meter (set on AC Volts) to check how much voltage is going between ground and hot, neutral and hot, and ground and neutral. It’s not as complicated as it seems. The first two numbers should read within a volt of one another and should be in the 110 to 127 range. The other reading should be less than 1 volt (0 is optimal). If anything’s off kilter I don’t plug in and head back up to the office for assistance – maybe a different site or for maintenance to come have a look. Sometimes it’s a loose wire, a worn out breaker or receptacle – sometimes it’s more serious.

At the very least, I recommend you do a polarity test outside and use a line voltage monitor plugged in to an indoor outlet to check the incoming volts.


Other power options include using your 12-volt system with an inverter, a generator or even solar power. The bottom line is knowing what you require to camp comfortably and assuring you have an adequate energy supply. So fire up the electric espresso machine or make a cuppa over a campfire. After all, camping is what you make it!!

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