What You Need to Know About Your RV Power Cord

Access to electric power allows RVers to enjoy all the comforts of home as we travel. Refrigerators, air conditioners, heaters, coffee makers, microwave ovens, television sets, computers, and the personal devices we use on a daily basis all require energy. And of course, we have batteries to charge. When we’re hooked up to shore power at a campground, the often overlooked piece of gear that carries that electricity into our RV is the ubiquitous RV power cord.

What is an RV Power Cord?

All classes of RVs have an RV power cord that runs from your rig to a power source.

For example, if you stay at a campground with partial or full hookups, you’ll have a power source at your campsite. Your RV power cord will plug into the pedestal, and that’s how you’ll power the outlets in your RV during your stay. It will also charge your batteries.

Types of RV Power Cords

RV power cords are available on RVs in 15-amp, 30-amp, and 50-amp versions, usually in lengths of 25 or 50 feet. Let’s talk about each version, and then we’ll address the issue of extension cords.

15-amp RV Power Plug

Everyone knows what a 15-amp RV plug looks like. It’s exactly the same as the 3-prong style you use to plug just about any type of electric appliance into a standard outlet in your house. It has two thin, vertical prongs (one is “hot” and the other “neutral”), and a third, round one, that connects to the ground wire.

Usually, the smallest RVs with the lowest load requirements have a 15-amp RV power cord, like small pop-up campers or very small towables. Typically, if the RV doesn’t have an air conditioner, its power demand is low enough that all it needs is a 15-amp connection.

The total amount of power you can use at any one time in a 15-amp RV at 120V service would be 15A x 120V = 1,800 watts.

30-amp RV Power Plug

A 30-amp plug on an RV power cord also has three prongs: one prong is a 120-volt hot wire, one is a neutral wire, and the third is a ground wire. In addition to being a physically larger than a 15-amp plug, the prongs are arranged differently, with the thin prongs being at an angle, instead of parallel / straight up-and-down.

Usually, mid-size RVs with lower load requirements have a 30-amp RV power cord. One example would be a Class B campervan with a single air conditioner.

To give you an idea of how much electricity a 30-amp feed brings into your RV, a 30-amp, 120-volt service = 3,600 Watts.

50-amp RV Power Plug

A 50-amp power cord (for larger RVs) has four prongs that correspond to TWO 120-volt hot wires, a neutral wire, and a ground wire. Even though it’s called a 50-amp connection, it actually supplies two separate 50-amp, 120-volt feeds.

As a result, a 50-amp feed brings a total of 12,000 watts into your RV with 6,000 watts from each hot wire.

Most 50-amp RVs are wired to use each side of the 120-volt service separately, sending 120-volts to two separate “legs” of service. Usually, half of the RV’s 120-volt circuits are powered by one leg, and the other half are on the other leg.

But it’s still the same 120-Volt system as on all smaller RVs. It’s only on a few very high-end motorhomes (usually bus conversions) that you might expect to see 240-volts available through this same type of plug… most often for supplying high-voltage power to a 240-volt dryer (and ONLY that circuit is provided 240-volts… everything else in the RV will be wired to use 120-volts from one or the other leg of power).

Never Plug into a Dryer Outlet or Outlet That Isn’t Rated for RVs

Speaking of dryers… Heed this critical warning: NEVER plug an RV into a clothes dryer outlet!

Many people are confused by this because your dryer’s outlet will look very similar to a 30-amp plug, ready to accept the three prongs.

But dryer outlets are wired differently than a 30-amp RV outlet and supply 240-volts as opposed to the 120-volts your RV is expecting.

Connecting to a 30-amp dryer outlet risks seriously damaging your RV’s entire electrical system and possibly even starting a fire.

Don’t do it. Ever!

How to Plug into Service that Doesn’t Match Your RV

Now, let’s talk about all the cool things you CAN do and how to do them safely, beginning with using RV power cord adapters, better known as “dogbone” adapters.

If you have a 50-amp RV (you can tell by looking at your shore power plug) and the only service available to you is 30-amp service, don’t despair! There are adapters for this purpose. They’re called dogbones because of their shape (thin in the middle and fat on both ends).

Using this example, if you want to plug your 50-amp RV into 30-amp service, you’ll need a 50-amp female to 30-amp male adapter. This will allow you to plug directly into 30-amp shore power and will not cause damage to your RV or the power service.

Another example would be to plug your 30-amp RV (again, if you’re unsure that’s what you have, just look at your power plug) into a 15/20-amp outlet at a campground… or at your home. It’s a common scenario for RV owners, and you can do it safely using a 30-amp female to 15-amp male adapter. Again, you won’t damage your RV or the power service. But…..

In both of the above scenarios, you need to be aware of the fact that you’re connecting to a lower-power supply than your RV is capable of using. That simply requires being thoughtful about how much power you use at any one time.

A 15/20 amp outlet can run items like a coffee maker, a hairdryer, or a toaster… but not all at once. So don’t make breakfast until you’re done drying your hair!

If you try to run more than the outlet you’re plugged into can handle, you’ll trip the circuit breaker. But it’s never a good idea to RELY on that happening (plus, it’s not all that convenient… you know it’s going to trip while it’s raining out, LOL!).

RV Power Cord Adapters

There are a couple of different RV power cord adapters available to you. It’s essential to get the correct type that corresponds with your RV’s application.

Dogbone Style Adapter Types

A dogbone style adapter has the two adapter plugs separated by a short, heavy-duty cord (making them LOOK like a dog’s bone). These will often have a molded handle on one side to make plugging it into, and removing it from, the power pedestal easier.

Let’s use the example of plugging a 30-amp RV into a 15/20-amp power pedestal using a dogbone adapter.

You’d plug your RV’s 30-amp power cord into the female end of the dogbone adapter, and then you’d plug the other end of the dogbone into the 15/20-amp service outlet.

Everything in the RV will have access to power… but, again, just be sure that you don’t try to run too many 120-volt devices at once, or you’ll end up tripping the breaker at the pedestal.

Running off a smaller power source than your RV is able to take advantage of isn’t a problem, as long as you keep that limitation in mind, and don’t overload the circuit by trying to use too much power at any given time.

• 50A Female to 30A Male Dogbone (connect a 50A RV to a 30A outlet)
• 50A Female to 15A Male Dogbone (connect a 50A RV to a 15A outlet)
• 30A Female to 15A Male Dogbone (connect a 30A RV to a 15A outlet)

Puck Adapters

Puck adapters work like dogbone adaptors by converting your RV’s plug to a different size/style. They’re a single small unit (like a small hockey puck) that has the necessary female outlet and male prongs to make the conversion, but don’t have the short length of cable to connect the two plugs, like a dogbone style adapter does.

 To use it, you’d connect your RV’s power cord to one side of the puck adapter and plug the other end into the power pedestal (or an electrical outlet at your home).

Puck-style adapters are convenient to use because of their smaller size, but have more limited options than dogbones do, generally being limited to 30-to-15 amp connections.

• 30-amp RV to 15-amp Outlet (connect a 30A RV to a 15A outlet)

Can I Adapt My RV Power Cord Up?

Adapting up? What’s that, you ask? In all of the scenarios we’ve discussed so far, we’ve only dealt with the situation of adapting a larger RV plug down to a smaller/lower-amp connection. But you CAN go the reverse direction. It’s rare, but you could be in a situation where you have your 30-amp RV at a campsite that ONLY has a 50-amp connection available. There’s a dogbone/adapter for that. Or to allow a 15-amp RV to connect to a 30- or 50-amp outlet.

• 30A Female to 50A Male Adapter (connect a 30A RV to a 50A outlet)
• 15A Female to 30A Male Adapter (connect a 15A RV to a 30A outlet)

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Do I Need A Dogbone/Adapter For Every Situation?

You may be wondering if you need to carry around a huge supply of electrical adaptors for your RV power cord, so you’re ready for every eventuality. While it’s a good idea to be prepared, you don’t need EVERY possible combination… just the ones you’d typically need for YOUR RV.

If you have a 30-amp RV, you’d likely only need a step-down adapter from 30A to 15A, so you could connect to a smaller outlet. The chances that you’d encounter a site with ONLY a 50A outlet are somewhat rare, but you could carry a 30-amp female to 50-amp male adapter, just in case. If you encounter this situation and DON’T have the necessary adapter… ask around. The RV park office may have one available for you to borrow.

For a 50-amp RV, you’ll want to carry two adapters: a 50A-down-to-30A (to connect at sites that only have a 30A outlet, or only 30- and 15-amp outlets, which is very common) and a 30A-down-to-15A adapter.

But, wait… how do you connect your 50A RV to the 30A-to-15A adapter? By combining them!

You first adapt your cord from 50A down to 30A using one adapter, then connect the 30A-to-15A adapter next. It sounds like magic, but it works fine!

See the photo to the left of John showing how we’re able to plug our 50-amp RV into a 15-amp outlet.

No need to have a single dogbone/adapter for every possible situation… combine them when needed and you’ll be able to plug your rig in just about anywhere.

Can You Use an Extension Cord for Your RV Power Cord?

Yes, you can extend your RV power cord’s length with an extension cord, but you must use one that’s properly rated to carry the amount of current you need to use. Never use a regular household extension cord for this purpose. Bear in mind that you’re dealing with high amperage (current) and will be using it outdoors. Standard, household extension cords aren’t appropriate for either of those issues!

The longer the distance that a cord will need to be run to get to power, and the higher the draw, the larger the cord needs to be. A long, thin cord rated for low power draw can overheat. This is no place to consider cutting corners!

Quality extension cords are readily available at reasonable prices. Most importantly, they include the right-sized wiring and safety features for the amperage you’re dealing with.

How Do You Know an RV Pedestal Is Safe to Plug Into?

How do you know that an RV power pedestal is safe to plug into? The short answer is you don’t.

So, RVers use a surge protector whenever they plug into a campground’s power pedestal. This is the only way to protect your RV if there’s a bad power pole or a surge.

Let’s have a closer look at why this is important:

An RV surge protector is meant to protect your RV’s electrical system from power surges or poorly-maintained power pedestals in campgrounds. A power pedestal may have faulty wiring, too-low voltage, or frequent power surges (including but not limited to lightning strikes). Any of these things can damage your RV’s electrical system.

In their simplest form, a surge protector plugs directly into the campground’s electrical service pedestal. You then plug your RV’s power cord into the other end of the surge protector. The surge protector acts as an intermediary or buffer for the power flowing between the campground’s pedestal and your RV… and will most often provide diagnostic lights/indicators to tell you if it detects something wrong with the park’s wiring.

There are other options for surge protection and low-voltage protection that can be permanently installed into your RV, eliminating the need to remember to plug them in when connecting at a campground.

Either way, the surge protector essentially monitors the power coming out of the pedestal before it gets to your RV so that if anything abnormal occurs, it won’t damage your RV’s electronics.

Now that you have a better understanding of your RV power cord and how to use it, you’ll have all you need to bring power into your RV while maintaining optimal safety standards as you enjoy the electricity in your home-on-wheels.

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