Best extension cords: Outdoor, heavy-duty, retractable, flat plug

There are several types of extension cords out there, each with its unique form, length, and even thickness. To most people who do not know much about extension cords, it can get overwhelming. This article aims to guide you through your purchasing decision and ensures that you choose the right cable for the type of work you will be doing.

What to look for

Several factors need consideration when looking to purchase an extension cord. Depending on your application, you may need a thick cable when planning to use it outdoors, such as supplying power to your backyard lights. If you need an extension cord when going camping, you can use an RV extension cord. For plugging multiple appliances in a single extension cord, you may need a multi-outlet extension cord. Whatever type of extension cord you plan to purchase, here are the common things to consider before deciding to purchase.

Indoor or outdoor

The first question you need to ask yourself is, “Will I use the extension cord indoor or outdoor?”. It varies for indoor and outdoor use, which means it is important to know your use case. Outdoor extension cords are usually thicker and waterproof since the outdoor environment is harsh and prone to dirt. The conductive part of the extension cord must have ample protection. On the other hand, indoor extension cords are usually thin. Contrary to the amount of protection outdoor extension cords need, indoor cords do not need a lot of protection. For as long as the conductive part has good insulation, it should be fine.

Buy longer ones

Aside from varying thicknesses, it also comes in several lengths. Be sure to give a bit of an allowance to the length when picking which one to purchase. For example, if your application requires 5m of cable length, you may want to choose the next available length. Doing so makes it future-proof in the next couple of years, which will save you money in the long run. However, it is important to keep in mind that using a length that is too long has its disadvantages.

The right wire gauge matters

Wire gauge size defines the diameter of the cable. Licensed electricians usually handle electrical work at home. However, it is not an excuse to know at least the basic things. In selecting the right wire gauge, electricians use a wire gauge size chart as their reference. In the United States, the standard wire gauge size chart is the American Wire Gauge, commonly referred to as AWG. The AWG is a sizing system that describes the specific diameters of solid round wires, referred to as the wire gauge, to use as the conductive material. The amperage capacity is the maximum current a wire gauge can handle safely.

It is important to know that the AWG numbering system is inversely proportional, which means a higher AWG number has a smaller diameter. On the other hand, a lower AWG number has a larger diameter. It means a 16/3 gauge extension cord has a thinner wire than a 14/3 gauge extension cord. To know more about gauge wires, you can refer to our article about 20, 30, 40, 50 & 60 Amp Wires, Breakers & Circuits or 70, 80, 100, 125, 150, 200, 400, 600 Amp Wire Size Guide & Chart.

Thicker cables can carry more power

As discussed in the previous section, a thicker cable can carry more ampacity than a thinner cable. The thickness of the conductive material inside a wire determines how much amps it can safely carry. Thick wires can carry more power over a given distance than thin wires. Most cords in an electrical store can safely meet the requirements of low-power devices like battery chargers, lights, or a stereo. Large appliances and power tools may require thicker cables as these consume more amps.

Quick tips on choosing and using extension cords safely

The information above may be overwhelming to some people. The below points can get you up to speed when choosing and using an extension cord safely.

  • You should only purchase extension cords approved by a testing laboratory.
  • When looking to use an extension cord outdoors, be sure to look for an extension cord safe to use outdoors.
  • Read the instructions before using an extension cord. The power it supports may vary per extension cord, so knowing these details is important.
  • Use an extension cord that can safely handle the devices you plan to attach with it. Refer to the AWG size. A smaller AWG number indicates a thicker wire, while a larger AWG number indicates a thinner wire.
  • Longer extension cords can handle less power than shorter extension cords. Don’t use extension cords that are too long. However, keep in mind to give a bit of an allowance when choosing a length.
  • Round, thick cords are best for large, heavy-duty appliances. For small, light-duty appliances, a flat, thin cord is enough.
  • There are some appliances you should not use with an extension cord, such as a dryer.

Outdoor extension cords

As you prepare to bring the lights to your front porch or back yard, it is important to know how to tell if an extension cord is for outdoor use. The safest and quickest way to know if it is for outdoor use is to check the packaging. If it is no longer available, you may refer to the cord itself. The letter W in the cord itself or the packaging indicates that the cord is for outdoor use.

The primary difference between an outdoor and indoor extension cord is the insulation of the wire’s conductive part. Most indoor extensions have a two-prong plug, whereas most outdoor extensions have a three-prong plug. The third prong is the ground, which reduces the risk of electrical shock and fire. Most outdoor appliances and devices use more amps than ones you use indoor.

To safely use an outdoor extension cord, here are some things to consider.

  • Store these properly. After use, carefully roll it back as it was brand new. Hang or store it somewhere dry and away from harsh external elements.
  • When getting an extension cord from storage, inspect for wounds or cracks in the wire before using it. If you notice any, do not attempt to use it.
  • Do not overload the extension cord by using too many appliances at once.
  • Avoid using a multiple outlets/three-outlet extension cord for outdoor use to prevent overloading.

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The placement of several appliances is away from an outlet, making extension cords a useful solution. A retractable extension cord is a practical solution for household purposes. It lets you adjust the length of the cord, allowing you to use it in any place you wish. Some people prefer to move appliances inside the house now and then, making a retractable extension cord a practical solution.

You can easily roll up the extension cord to avoid messy wires around the house. Since children are playful and move around a lot, they may trip over unkept wires if carelessly left on the floor. A retractable extension cord systematically organizes your wires, so you will not have to worry about any tripping mishaps.

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Surge protector

If you need to add more outlets or need an additional layer of protection for your gear, getting a surge protector extension cord is a great choice. This type of extension cord offers a level of protection against power spikes. How well and much it can handle will vary greatly. When looking for a surge protector extension, notice the joules value as it tells the amount of protection it can offer. Generally, a higher joules value is better as it can offer more surge protection. The parts inside will wear down over time, reducing their effectiveness in the long run.


Heavy-duty extension cords are ideal for appliances that draw many amps of power. If you have appliances that draw ten amps to fifteen amps of power, using a heavy-duty extension cord is the ideal solution. This type of extension cord comes with a third wire, which serves as the ground. It has plugs with three slots for accepting grounded appliances and device cords. The most usual use case of a heavy-duty extension cord is power tools and heating appliances that draw up to fifteen amps of power. Use a 12/3 wire for a cord length of up to 50 meters. On the other hand, use a 10/3 wire for a cord length of up to 100 meters.


A flat-plug extension cord provides a slim design and a right-angle plug, making it easy to move and place furniture in front of it. On top of having a flat design, some of these plugs feature 360 degrees rotating flat supply plug, adding more versatility to the extension cord. It is best to use it in tight spaces, such as behind furniture, bookshelves, desks, or almost anything near a wall. Depending on the AWG size of the wire, it comes in varying wire thickness.

RV extension cord

Almost all RVs come with a built-in cord, which you can use for almost anything you might need during your camp out. Your RV will require 30 amps or 50 amps plug to connect to the power source. The built-in cord comes at a fixed length, which may be insufficient if the power source is too far from the RV. To go about it, use an RV extension cord to reach the power supply. We recommend using an 8/3 or 10/3 wire. Due to the thickness of these wires and the jacket’s durability, they can run in high lengths.

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Multi-outlet: 2-prong & 3-prong extension cords

Multi-outlet extension cords come in two-prong or three-prong variants. If you are in the market looking for an extension cord with multiple outlets, it may come as a shock to you that they in a few types, with the two-prong and three-prong as the most common. These extension cords have at least two sockets, making them ideal for people who would like to plug in a few devices. However, keep in mind to get a wire thick enough to handle the load.

These two are not much different from each other. The main difference between these two is that the two-prong does not come with a ground wire, whereas the three-prong comes with one. A ground wire directs any excess electricity to flow into the ground, preventing any severe damage from happening to your appliances.

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Welder extension cords

Welder extension cords add extra portability to a welder. However, there are a few things you need to consider when buying one. The power supply, length of cord, and the welder all affect its safety factor. A safe welder extension cord can safely accommodate the power draw of a welder while staying within the limits of the wire. Choose an industry-standard cord that is heavy-duty and can maintain a stable energy transfer. You need to match the voltage of the power source, whether it is 110V or 220V. Using thick AWG cords can accommodate the flow of more electricity to your welder.


When looking to use an extension cord with a power generator, you should only use it to power items outdoors. Indoor items connected to a generator should only be powered using a transfer switch. Using an extension cord to provide temporary power to indoor items increases the risk of exposure to carbon monoxide gas. Running extension cords from the outdoors through vents, windows, or doors may cause damage to the wire, which may lead to more serious consequences. Using a wire that can carry a total load of all devices prevents overloading.

Dryer & air conditioners

Normally, you should install an air conditioner near an outlet. If that is not possible, you can use an extension cord to power your air conditioner. It is important to use a heavy-duty wire. Most air conditioners consume about 12 amps of power, which means using at least a 12-gauge wire is recommended. However, keep in mind using an extension cord to power your air conditioner should only be a temporary solution. For dryers, you can use a three-prong dryer cord with at least a 12-gauge wire. For HVAC systems, be sure to check out our post on UV light sanitizers as well.


A ground-fault circuit interrupter extension cord prevents electric shocks from happening at your workplace or home. It protects people from fatal electrocutions. A GFCI detects ground faults, which stops fire before occurring. It works by monitoring flowing electricity in a circuit. If any discrepancies occur in the flowing and returning amperage current, the GFCI switches off the power. It protects the user from electrocution. A GFCI extension cord is durable and strong, which is why manufacturers usually use at least a 12-gauge wire.

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