Best 15, 20, 30, 50 amp & RV Extension Cords

When looking for an extension cord, it is important to pick one that meets your needs. There are several reasons why getting one is beneficial, but the most common is not having easy and close access to an outlet. For example, if you need to set up a few lights in the middle of your backyard, you can use one to extend the range of the nearest outlet. Before we proceed, it is important to know that you cannot just use any wire. Similar to AWG wires, they have different sizes, lengths, and types.

two electrical cords plugged into each other

They come in several lengths, which you may or may not notice when taking a trip to an electrical supply store. Some available lengths are 15 feet, 20 feet, 25 feet, 30 feet, 50 feet, and 100 feet. Your mind might be telling you to pick the longest length available, but that should not always be the case. A recent study conducted by the United States Consumer Product Safety Commission highlights that they are among the leading causes of fire accidents. The main reason is due to incorrect length and size.

With that said, consumers should at least know the basic principles behind extension cords. In this article, you will know some of the important things to consider when looking for the best RV options and the right capacity for your needs. Everything in this article may not be important to you. We conveniently labeled each section for you. You can skip to this section by using your browser’s search functionality, no matter if you’re on the lookout for the best 15, 20, 30 or 50 amp extension cord, or perhaps one for your RV!.

What to look for?

It is safe to assume that each household has at least one lying around at home. One might think all of them are the same. However, most people do not understand the differences in environmental compatibility, gauge, and purpose matter. Consumers need to realize that they are always a temporary solution to a problem. You should avoid using it as a long-term solution in extending your household’s electrical system. If you think you need a long term solution, it is better and safer to contact a licensed electrician for consultation.

What to look for
Gauge Frequency of use Indoor vs outdoor cords

Although an extension wire is simply a cord that extends an outlet’s reach, it comes in different forms and sizes. It also comes in several types of plug, such as a twist-lock or a 3-prong. Below are some of the important things you should be looking for.

overloaded extension cord

The gauge is important

They come in different sizes, just like how AWG wires come in several sizes. We classify them into three categories – occasion use or light-duty, medium to frequent use or medium-duty, and rugged use or heavy-duty. We use these terms to refer to the wire’s size. It indicates whether a particular cord will work safely for heavy, continuous use, such as heaters, power tools, and computers. If it is your first time looking at gauge numbers, it might confuse you. It is important to know that the number is inversely proportional to the diameter, which means a 10 is thicker than a 16. The former can handle high capacity while the latter cannot. Thicker ones can handle more electricity at any given time, which means it is suitable for heavy-duty tools that demand high power.

At this point, you now have an idea of the importance of a gauge. So what happens if you pick the wrong size? It will potentially burn if you choose an incorrect size. It can also cause damage to your equipment or start a fire at worst. It is advisable to know which to use to prevent bad things from happening. People who are not aware of the importance of size usually use smaller sizes because they are cheap, thinking it would not make any difference. Undersizing it may only cause you more in the long run. Opting for a larger wire is the best way to go, even if it is more than the recommended size. The only negative it may have is on your budget, which will cost more upfront.

Choosing between indoor or outdoor options

You can use them indoors or outdoors. The latter uses a tough rubber, vinyl, or plastic cover for maximum durability. In most cases, an indoor one is cheaper, which is why people prefer to buy these rather than getting the one that they really should be getting. It could lead to electrocution, failure, overheating, or fire. What you need to do first is to know where you will be using it. If you have the budget, immediately go for an outdoor one so you can enjoy it indoors and outdoors. It is going to cost more, but its use case is more flexible than the other one.

Frequency of use

extension cord

There are three main categories for how frequently you use a cord. Occasional use cords are usually thin and lightweight. They come in 16 or 18-gauge that can easily handle 12, 13, or even 18 amps. Some light-duty indoor appliances examples are portable fans, electric hedge trimmers, vacuum cleaners, and holiday lights.

In the case of appliances and tools you need to power frequently, such as television sets, power drills, electric chainsaws, snow blowers, and table saws, you should consider getting a 14-gauge cord. It is the ideal size for frequent or medium-duty applications.

Lastly, for heavy-duty and extra heavy-duty applications, we recommend getting at least a 12 cord. Any size thicker than this should do well too. The heavier weight of rugged cords allows them to withstand extreme weather conditions. They are also suitable for very high-requirement tools, such as air compressors and generators.

Looking at the wire’s jacket, you will see a designation letter. Below are some definitions to know.

  • S – The cord is flexible, which is great for general use.
  • W – The cord is for outdoor purposes, but will also be able to be have it satisfy your indoor needs.
  • J – The cord has a standard 300 V insulation. Otherwise, it has a thicker 600 V insulation.
  • O – The cord is oil-resistant.
  • P – It has a parallel construction, which is good for household purposes
  • T – The jacket is made of vinyl thermoplastic.
  • E – The jacket ise madea of thermoplastic elastomer rubber (TPE).

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How many amps can you run through an extension cord?

The number of amps you can run through one depends on the AWG you are using. Like an electrical wire, extension cords also follow a chart, which determines the number a particular size will support.

Let us look into the chart below. A 6 is the minimum safe choice if you have a supply power of 50 amps. On the other hand, you can use a 10 copper one at 167°F if you have a supply of 35. Look at the table if you need help in determining the ideal AWG for your needs. If you are a camper going on a trip, you may want to opt for thicker options as they can withstand the outdoors.


Aside from the capacity requirement and ambient temperature rating, knowing if the conductor is aluminum or copper is important too. Copper is able to carry more current than aluminum at the same AWG. It means if you have a 10 aluminum wire and a 10 copper wire, the latter will likely support more than the former. Moreover, gauges can carry more current at a higher ambient temperature rating. If you look at the table above, a 6 wire with an ambient temperature rating of 167°F can only carry up to 65 amps, whereas the same gauge with a higher ambient temperature rating of 194°F will carry up to 75.

As discussed in the previous section, the AWG has an inverse relationship to the diameter. A 6 gauge has a diameter of 4.115 mm, whereas a 10 has a diameter of 2.588 mm. It shows that the higher the AWG number, the thinner the diameter.

These factors make it a challenge to pick the correct AWG for your requirements. Always remember that choosing a thicker one than the recommended one is not a problem.

15 amps

For 15 amps, you need at least a 14-gauge copper wire at an ambient temperature rating of 194°F or lower, or a 12 aluminum wire at an ambient temperature rating of 167°F. Heating appliances and a few tools are a few things that utilize around this amount of power.

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20 amps

Twenty amps of power would need at least a 12-gauge aluminum wire at an ambient temperature rating of 167°F. If you prefer copper, you may do so at ambient temperature ratings of 140°F, 167°F, and 194°F. Typical appliances that consume this amount of current are generators, power tools, vacuums, lawn equipment, chargers, and heaters.

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30 amps

For 30 amps of power, you need at least a 10-gauge aluminum wire at an ambient temperature rating of 167°F. If you prefer copper, you can opt for an 8 copper wire at ambient temperature ratings of 140°F, 167°F, and 194°F. These are usually for RVs, trailers, campers, and vehicles.

50 amps

Fifty amps of power need at least a 6-gauge aluminum wire at an ambient temperature rating of 167°F or an 8 copper wire at an ambient temperature rating of 167°F. You can also go for any AWG that is thicker than a 6. You may use this cable for several applications, such as trailers, vehicles, campers, and RVs.

How far can you run a 30 amp cord to a camper?

In most cases, any length between 25 feet to 50 feet should do you fine. Most RVs come with a standard cable length of 25 feet. You may go as long as 50 feet, but always keep in mind that an increase in an length also increases electrical resistance, which then generates more heat.

Can you connect two cords together?

Daisy-chaining is the connection of two or more cords to cover a longer coverage. Although you can connect two of the same cords together, you should not do it. Connecting two or more cords could cause the power strip or power outlet to overload, leading to a meltdown or fire.

What do I need for a 50 amp plug?

For a 50 amps plug, you can use an 8-gauge copper wire or a 6 aluminum one. The copper and aluminum wire should both have an ambient temperature rating of 167°F or lower.

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Can I plug my 30 amp into a 50 one?

No, you cannot plug a 30 into a 50 amp, or vice versa. The main reason is the physical differences between them. However, there are also differences in the electricity they provide.

A 30 amp plug usually features a 3-prong plug with a 120V hot wire. It carries current along with a neutral prong and a ground wire. RVs with low power requirements usually this system. On the other hand, a 50 amp plug usually has a 4-prong plug, which can supply two 120V lines. Large RVs with an air conditioner and a few appliances often need a 50 amp system.

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