Best Gauge Extension Cords

What extension cord gauge do I need? That’s a good question that you will get answered in this article.

Extension cords play a vital role in almost everyone’s life. Not all the time, an outlet is close enough to access. In this case, you will need one from a nearby outlet to your location.

Many times it has made it easy for people to the plugin. It enables people to recharge a device or supply power to an appliance. They can also provide light. Just like AWG wires, they come in different forms & types.

Summary

We tested a number of products and found that Southwire was the best extension cord manufacturer across a number of gauges. Here are our recommendations for various gauges:

Here’s a quick look at our recommendations:

Brand
Southwire
Champion Power Equipment
Otimo
addlon
Image
Southwire 19178806 8/3 Heavy-Duty STW 40-Amp/250-Volt Nema 6-50 Blue Welder Extension Cord; 25- Feet; 8-Gauge; STW jacket for Superior Performance; Rated at 40 Amps; 250 Volts and 10;000 Watts
Champion Power Equipment 48034 25 ft. 30A 125V Generator Power 3750 Watts (L5-30P to Three 5-15R) Extension Cord, yellow
Otimo 25 Ft 12/3 SJTW Red, Heavy Duty Outdoor Extension Cord - 3 Prong Ground Plug, 15A 1875W, Water & Weather Resistant, Flame Retardant
addlon 25 Feet Outdoor Extension Cord Waterproof Deep Black 16 AWG 3 Prong, Flexible Long Wires Perfect for Home or Office Use, UL Listed
Gauge
8
10
12
16
Rating (Amps)
40
30
20
13
What we love
Great 8 gauge extension cord for heavy duty work.
Awesome 10 gauge extension cord for generators & more.
Impressive 12 gauge extension cord for everyday use.
Good, budget 16 gauge extension cord option.
Brand
Southwire
Image
Southwire 19178806 8/3 Heavy-Duty STW 40-Amp/250-Volt Nema 6-50 Blue Welder Extension Cord; 25- Feet; 8-Gauge; STW jacket for Superior Performance; Rated at 40 Amps; 250 Volts and 10;000 Watts
Gauge
8
Rating (Amps)
40
What we love
Great 8 gauge extension cord for heavy duty work.
Brand
Champion Power Equipment
Image
Champion Power Equipment 48034 25 ft. 30A 125V Generator Power 3750 Watts (L5-30P to Three 5-15R) Extension Cord, yellow
Gauge
10
Rating (Amps)
30
What we love
Awesome 10 gauge extension cord for generators & more.
Brand
Otimo
Image
Otimo 25 Ft 12/3 SJTW Red, Heavy Duty Outdoor Extension Cord - 3 Prong Ground Plug, 15A 1875W, Water & Weather Resistant, Flame Retardant
Gauge
12
Rating (Amps)
20
What we love
Impressive 12 gauge extension cord for everyday use.
Brand
addlon
Image
addlon 25 Feet Outdoor Extension Cord Waterproof Deep Black 16 AWG 3 Prong, Flexible Long Wires Perfect for Home or Office Use, UL Listed
Gauge
16
Rating (Amps)
13
What we love
Good, budget 16 gauge extension cord option.

Why you can trust us & how we picked

We’ve tried and tested all the extension cords we have posted on this page. We have also written extensively on electrical topics and feel we know what we’re talking about. We picked extension cords with different capabilities to reflect the different needs people have.

If you have ever been to an electrical supply store, you will notice they come in different lengths and sizes. The most common length are 25 ft, 50 ft, 100 ft, and 200 ft.

In a recent study by the US Consumer Product Safety Commission, extension cords are among the most dangerous electrical products for home use.

The main reason it is dangerous is the incorrect size and use. With that said, people need to know how to prevent them from failing.

Table of Contents

Best 6 gauge

A 6-gauge aluminum extension cord has a rating of 50 amps at an ambient temperature of 167°F or 60 at an ambient temperature of 194°F.

A 6-gauge copper extension wire has a rating of 55 amps at an ambient temperature of 140°F. It’s rated 65 at 167°F and 75 at 194°F. Some thick extension cords are waterproof. It is best practice to check the specifications.

Here’s a great option from PrimeWeld.

Pros

  • It can handle 50 amp welding jobs.
  • It will be able to handle most electrical needs you have.
  • It works for most welders on the market.
  • PrimeWeld is a major player in the welding space.

Cons

  • It’s only 50′ long.
PrimeWeld 
It's great for welding.

8 gauge

An 8-gauge aluminum extension cord has a rating of about 40 amps at an ambient temperature rating of 167°F or 45 at an ambient temperature rating of 194°F. An 8-gauge copper extension cord is rated at 40 amps at an ambient temperature of 140°F. It’s rated 50 at 167°F and 55 at 194°F.

Aside from knowing the above information, the safe length for an 8 AWG wire is also important. An 8-gauge extension cord wire is thicker than a 10, making it more heavy-duty than the latter.

It comes in several lengths. Some of them include 25 ft., 50 ft., and 100 ft. You can use an 8-gauge 50 ft. extension wire with a welding machine. Some long cables are retractable, making it easy to pack them up.

Pros

  • It’s 40 feet long.
  • We love the molded plug.
  • It’s very durable.
  • It worked with the MIG welder we tried it with.

Cons

  • They don’t sell options longer than 40 feet.
RVMATE Store
For your heavy electrical needs.

Aside from metal welding, there are other welding types available. Some of these types are gas welding and glass welding.

10 gauge

How many Amps & Watts Can it Handle?

A 10-gauge aluminum extension cord has a rating of 30 amps or 3600 watts at an ambient temperature of 167°F or 35 at 194°F. A copper wire of the same AWG has a rating of 30 at 140°F. It’s rated 35 at 167°F and 40 at 194°F.

You can use a 10/3 with a ground wire for an apartment. They’re great for a large air conditioner or an electric dryer. Only appliances mentioned with a rating of up to 30 amps are compatible.

Note that some of these appliances use a NEMA 10-30 three-prong plug, so you may want to pick a multi-outlet option.

Name10/3-3 Triple Outlet Ultra Heavy Duty
Gauge10
Length100′
NameGearIT
Voltage125 Volts

Pros

  • It’s 100 feet long.
  • They have many cords available to choose from.
  • We love the 3-outlet plug.

Cons

  • It might be a bit pricey.
  • It still twists and kinks like other cables.
Sale
GearIT Store
It's a bit thinner.

12 gauge

red extension cord on the floor

A 12-gauge aluminum extension cord has a rating of 20 amps at 167°F and 25 at 194°F. A copper wire of the same AWG has a rating of 25 at 140°F. It’s rated 25 at 167°F and 30 at 194°F.

You can use a 12/3 cord in various appliances and tools, such as but not limited to:

  • air compressors,
  • saws,
  • drills,
  • lawn equipment,
  • vacuums,
  • chargers,
  • heaters,
  • and generators.

Some options come in a male-to-male or double-male format. However, never use this as it is dangerous and prone to fire.

Name12/3 Outdoor Extension Cord
Connector GenderMale-to-Female
Gauge12
Input Current20 Amps
Length25′ – 100′
StoreAddlon
Voltage125 Volts

Pros

  • They offer 25 to 100 feet cords.
  • It’s reasonably priced.
  • We love that the ends light up.
  • Shipping was done nicely.

Cons

  • We found no proof it’s ETL-listed.
addlon Store
It's 25 feet long.

14 gauge

In the case of a 14-gauge extension cord, it usually only uses copper for the conductive part. It has a rating of 20 amps at an ambient temperature rating of 140°F and 167°F and 25 at 194°F.

16 gauge

A 16-gauge extension cord has a rating of 13 amps, which you can use for a light-duty job. This type can only support devices that are not power-hungry. It is dangerous to use it with a space heater or any heat-generating appliance, such as toasters.

extension cords tangled up

Gauge Chart

As for wires, we also have an extension cord gauge chart. It determines how many amps a particular AWG wire can handle. It will help you realize which option is right for you, whether it’s 10 or 14.

It depends on the wattage and size you require. The appropriate amp rating is crucial to ensure it can handle the electrical amount according to your requirements!

[rtbs name=”extension-cords”]

The chart above indicates that a 12 aluminum wire is a safe choice for your 220V 20 amps at 167°F ambient temperatures. Similarly, you can use a 14-gauge copper wire for 220V 20 amps at 167°F. If you seek one out for your washing machine, you can use the chart above as a guide.

The AWG wire for a certain ampacity depends on a few factors, such as the conductive material and the ambient temperature rating. It is important to know the conductive material you plan to use.

When using aluminum as the material, you will refer to the aluminum column. If you are using a copper wire, you must refer to the copper column. There are a few of these for the ambient temperature rating, so keep that in mind.

extension cord for iphone

Copper can carry more ampacity than aluminum at the same AWG. In other words, an 8-gauge copper wire can support more ampacity than the equivalent aluminum one. Having a higher ampacity means it can allow more current to flow at any given time.

Ones with a high ambient temperature rating can carry high loads of power. It explains why a 12-gauge copper extension cord with an ambient temperature of 140°F is compatible with 20 amps. The same at a higher ambient temperature of 194°F can carry up to 25 amps.

The outlined factors above make it tricky to choose the correct rating. Always remember that it is fine to pick a thicker one than the recommended one. However, never choose one size smaller than the recommended option.

Make sure to also check out our resources on the best plasma cutters and the best TIG welders.

What rating should I use?

overloaded extension cord

Getting the correct one is very important. Choosing a smaller one can ruin your tool or even start a fire. In most cases, a common small hand-held electrical tool can operate without any danger with a 16-gauge extension cord about 100 feet long. Reading through this section will guide you in determining the correct one to use.

Obtaining the rating

The first thing to do is obtain the motor amperage from the tool’s plate. This information is usually in the small metal plate, where you can find the model number and serial number. An outdoor circular saw shows 15A, which means it has a rating of 15 amps.

Ohm’s Law

extension cord

Knowing Ohm’s law is important because it helps in keeping you safe when dealing with electricity. To put it in simple terms, you multiply amps with volts to get watts.

Volts (V) x Amps (amps) = Watts (W)

This formula helps understand the different sizes because it may require you to convert the rating in the tool or appliance to watts. In the US, we use 120 volts in most homes. Some regions across the globe use 240V. It may vary depending on which region you are in, so check before proceeding.

Voltage Drop

When electricity travels down a long wire, it loses voltage. It happens because electricity encounters resistance as it travels. With this knowledge in mind, only use the cord length that you need. It is one of the many reasons why using the correct wire size and length is important. Electrical resistance creates friction, which also creates heat.

To test this out in a simple real-world experiment, rub your hands together. When you do it slowly at first, you may not feel much. As you gradually increase the speed, press down harder.

You may feel the heat building up, and it becomes rougher to rub your hands. It is because resistance is building up. The same happens with electricity traveling down an extension cord.

To summarize, do not use a 50 feet long extension cord if you only really need about 20 feet. Purchase an assortment of options with varying lengths. You can use a short one if the outlet is only a few yards away from your project.

If you have a project that needs welding, it will surprise you that several types of welding may need different types of cables. You can look into gasless MIG welding and aluminum welding.

Indoor extension cord

Sizing

The first thing you need to do is determine the tool or appliance you will be using. Once you have the information on hand, look into the Electrical Wire Size Chart table. This chart determines the compatible AWG number.

Below is a list of common electrical tools with their respective amp ratings to make things easier.

  • Circular saw: 12 – 15
  • Electric Chainsaw: 7 to 12
  • Electric Lawn Mower: 6 to 12
  • Hedge Trigger: 2 to 3
  • Leaf Blower: 6 to 12
  • Power Drill: 3 to 7
  • Reciprocating Saw: 6 to 8
  • Router: 4 to 6
  • Table Saw: 14 to 20
  • Weed trimmer: 2 to 4
  • Lamps: 18

There are several engine-driven welders available in the market. If you are looking for a list of the best, look no further because we have a curated list of the best engine-driven welders.

extension cord

Can you connect different ratings?

Attaching two or more cords can sometimes be the only solution if you want to extend the length of coverage. However, this is not a good idea at all. If you practice this at home, immediately unplug them and buy a longer one to serve your needs.

There is a consideration in stringing two or more together. It has to be for a short term, temporary use only. The problem is that it creates a risk when using it as a long-term solution. Extending one with another could drastically reduce its wattage capabilities. It could lead to a meltdown and fire at worst.

The Consumer Products Safety Commission estimates 3,300 residential units catch fire each year, which is the reason. The common causes include misused or damaged cords or overloaded circuits. Connecting two different ones is one example of misusing it.

Avoiding the use of extension cords is the ideal solution. However, consider using a short one with adequate protection and heavy insulation if this is not possible. There are times it is unavoidable not to use one. In this case, use the shortest length and the correct size.

two electrical cords plugged into each other

Factors to consider

Looking for an extension cord is an overwhelming task, especially if you do not know a lot about it. It’s at least the case if you aren’t simply buying one of the most common ones. If you need to provide electricity for more powerful tools, find the right one. Here are the factors to consider when shopping for extension cord in different gauges online or in-store.

Purchase a slightly longer option.

Although we do not recommend getting a length that is way longer than you need, it is good to get the next longest cord. If the next available size is way longer, you might want to reassess your measurements.

It is important to know that you should not daisy-chain them. Plugging them into each other without having thicker wires to compensate for the distance could add electrical resistance between the outlets.

High electrical resistance results in voltage drop, which leads to a lower power supply to your equipment. Daisy-chaining them causes unnecessary heat from building up, increasing the fire risk.

Thicker ones can carry more electric power.

monitor connected to an extension cord

The thickness determines how much electricity can safely flow through it. A thicker one can safely carry more electricity over a longer distance. A shorter wire can safely carry electricity over a shorter distance.

Thin cables are ideal for low-power equipment such as battery chargers and lights. If you plan to use it in power tools such as vacuum cleaners and saws, you will have to choose a thicker one. The 14-gauge is the thinnest we recommend at 25 feet or shorter lengths.

Using it for cold weather.

Some cords are more flexible in cold weather conditions. These are easier to stretch out and bend across your workspace and easy to keep and store. They are flexible in tight spaces.

It is hard to determine if a cord is flexible without actually opening the package when you’re at an electrical store. The best way to ensure flexibility is by looking for one compatible with lower temperatures. The weatherproof ones are great.

Skip multi-outlet ends for heavy-duty tools

Getting a multi-outlet extension cord is tempting because you can plug several tools into it. Getting one is fine if you plan to use it on light-duty equipment. We do not recommend a multi-outlet cord for heavy-duty equipment because it is easier to overload.

For example, an extension can easily handle a circular saw. If you plug in a few other tools into it, you might overload the plug. It could cause a meltdown or start a fire.

extension cords outside

How to tell the gauge of an extension cord

There are several gauges you can use. Most will have a print of their rating somewhere on the wire. It may be too small to find, so carefully inspect it. For brand new products still in their original packaging, read through the product specifications. The size should be somewhere there.

Doing a quick bend test is another way to know what type you have. Although this is not a reliable way of determining the size, you get at least an idea. If it is hard to bend or curl, it is probably 16 or 14-gauge or less. Otherwise, it could be 18-gauge or more.

If you want to purchase a mini metal lathe, you should check this curated list. It consists of a list of the best options you can find in the market.

I have a need for 15 amps

If you have a 15 amps appliance or tool, we recommend using a 14-gauge copper wire. If unavailable, you can pick larger diameters. Choose a 12 or 10-gauge. You can get a bigger wire when choosing the AWG size without worrying about compatibility issues.

Electrical safety: Do’s and Don’ts!

An extension cord is an electric wire with multiple outlets on one end and a plug. It is an important and necessary piece of equipment that allows users to reach inaccessible electrical outlets located too far away for their devices.

However, using them is not without risk.

Now that you know how to purchase this important home equipment, it’s essential to know how to maintain safety around it. Even if they are a handy piece of electric equipment, they can be a fire hazard or a tangled mess that can lead to accidents. Each year around 3300 home fires are caused by careless use.

The US Consumer Product Safety Commission reports that around 2000 injuries caused due to negligent use are reported in hospital emergency rooms each year. These mostly include fractures, lacerations, sprains, and sometimes electric shock.

The Electrical Safety Foundation International has recommended tips for you to keep the electric wiring running cautiously. Here’s how you can keep your family safe and tangle-free!

DO’s

  • The first thing to do after purchasing a cord is to read its user manual. You will need to follow instructions on how to install and maintain the appliances that they will be attached to.
  • Always unplug when not in use: If you’ve got a toddler roaming around. You wouldn’t want them sticking fingers in where they’re not required.
  • Throw away any damaged or exposed wires and equipment. Any neglect in doing this could result in an electrical outage or a fire hazard.
  • Check the panel when in use. If it feels hot to the touch, consider buying a new one.
  • Make sure the power strip is rated for the plug you use it in. Strips marked outdoor and indoor must be used as such. Outdoor power cords are typically bright orange in color, perfect for lawn mowers.
  • Three-pronged plugs or polarized plugs must be preferred when buying.
  • Your cords must be approved by an independent testing laboratory, like the Canadian Standards Association (CSA) or Intertek (ETL).
  • Always pull the plug to disconnect and not the wire.
  • Always match the wattage rating on the appliance with the rating on the cord and never use one with a lower one than the appliance in use.
  • Buy the correct length and never longer than you need. Not only can it create a fall hazard, but shorter lengths of the same gauge can carry more currents, so they are more economical.
  • All cords should be stored in a dry place indoors when not in use, whether marked for outdoor or indoor use.
  • Use a gauge 10 for a 30 amp circuit breaker connection.
  • Make sure the power cord length doesn’t have a significant voltage drop.

DON’Ts

  • Never substitute temporary power strips for permanent wiring. If you’ve been doing this for a while, it may be time to get the house rewired.
  • This may or may not be an obvious one: don’t ever plug one extension cord into another. It may be a tempting idea if you want to increase the length of your wire. But it’s a fire safety hazard for innumerable reasons, and we’d strongly advise you to buy a new, longer wire instead.
  • Never allow them to run through water or snow, and keep their path unobstructed and clear. If you’re going to be using them in a damp place, only plug them into a Ground Fault Circuit Interrupter. A GFCI monitors the flow of current in a circuit. Any fluctuation or disturbance in the current will enable the GFCI to shut down the entire circuit. This is how a GFCI protects homes from electric fire hazards, even in damp areas like bathrooms where water and electric flow are likely to cause disasters.
  • They should be kept uncovered with no cloth or flammable material around in case they catch fire from the heat generated.
  • No more than one appliance should be attached to one panel of a temporary power strip. An overload on the appliance can cause circuits to burn out.
  • They should be kept away from areas with heavy footfall in case of a trip and fall.
  • Don’t bend or coil the wires when they’re plugged in.
  • Do not nail any cord to the walls or floors. They should not even be running under any furniture.
  • Do not remove any part of the plug, like the grounding pin, to fit it into a two-pronged outlet. No round pegs in a square hole, please!

Apart from these tips, it’s essential to check up on appliances around the house and make sure they are fit for use too. Old hairdryers and faulty chargers must be replaced and upgraded to avoid accidents in case they burn out. It can be caused by excessive usage or faulty wiring issue.

plugged in extension cord

Designations

When you buy any electrical equipment, it’s important to know its proper usage and terminology before installing it. Here are some terms that designate cords into several categories. Read up on these and only buy the correct strip for your project.

  • S – These are made for general use. These cannot be used outdoors under any circumstances and are only fit for indoors.
  • W – Now, these are rated for outdoor use. You can use them in your backyard or front lawn without any worry of an electric shock from moisture.
  • J –These are rated for a standard 300 voltage insulation.
  • T – This indicates it is made from Vinyl thermoplastic.
  • E – This indicates the wire is made from TPE.
  • P – This stands for parallel wire construction.
  • O – These are the special kind that is resistant to oil.

You may already have some extension cords lying around the house, but it is risky to use if you’re not sure what the gauge capacity is. Let’s look at how to find out the Amp of the cord.

That’s it, folks!

We hope you will experiment and try out our purchasing tips on your next run for this addition to your home. Our electrical safety tips certified by the ESFI are especially important to read over before you begin any new DIY project or installation in your home. Remember to consult a professional when in doubt regarding any electrical work.

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