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 plug-in. It enables people to recharge a device, supply power to an appliance, or provide light. However, just like AWG wires, they comes in different forms & types.
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 for it being dangerous is because of incorrect size and use. With that said, people need to know how to prevent them from failing.
We understand you may not be interested in all the gauges in this article. To make it easy for you, you can jump to the section you would like to read using your browser’s search functionality. Whether you’re looking for a 6, 8, 10, 12, 14 or 16 gauge extension cord, we have listed the best extension cords for various uses. With this guide, you’ll quickly find out which size is right for your project.
Electrical Extension Cord Gauge Chart
Like for wires, we also have an extension cord gauge chart, which 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, 12, 8, 16 or 14, depending on the wattage and size you require, with the appropriate amp rating.
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 a 220V 20 amps at 167°F. If you seek one out for your appliances, such as a washing machine, refrigerator, or television, 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 an aluminum as the material, you will have to refer to the aluminum column. If you are using a copper wire, you must refer to the copper column. For the ambient temperature rating, there are a few of these, so keep that in mind.
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 high loads of power. It explains why a 12-gauge copper one with an ambient temperature of 140°F is compatible with 20 amps, whereas 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 a one size smaller than the recommended option.
What rating should I use?
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 or problems with a 16-gauge extension cord that is 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 to 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. For example, an outdoor circular saw shows 15A, which means it has an rating of 15 amps.
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.
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 length that you need. It is one of the many reasons why using the correct wire size and length are 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 meters away from your project.
In case you have a project that needs welding, it will surprise you that there are several types of welding that may need different types of cables. You can look into gasless MIG welding and aluminum welding.
The first thing you need to do is determining the tool or appliance you will be using. Once you have the information on hand, look into the table in the Electrical Wire Size Chart section. This chart determines the compatible AWG number.
To make things easier, below is a list of common electrical tools with their respective amp ratings.
- 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
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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. However, it has to be for a short term, temporary use only. The problem with it 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 with this being the reason. The common causes include misused or damaged cords, overloaded circuits, and short circuits. Connecting two different ones is one example of misusing it.
Avoiding the use of extension cords is the ideal solution. However, if this is not possible, consider using a short one with adequate protection and heavy insulation. There are times it is unavoidable not to use one. In this case, use the shortest length and the correct size.
What to look for
Looking for an extension cord is an overwhelming task, especially if you do not know a lot about it, at least if you aren’t simply buying one of the most common ones, but if you need to provide electricity for more powerful tools. Here are some points to consider when you are shopping for one online or in-store.
Purchase a slightly longer option
Although we do not recommend getting a length that is way longer than what you need, it is good to get the next longest cord. However, 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 risk of a fire. If you are looking for a waste oil heater, we have a curated list for sale.
Thicker ones can carry more electric power
The thickness determines how much electricity can safely flow through it. A thicker one can safely carry more electricity over a longer distance, whereas a shorter wire can safely carry electricity over a shorter distance. Thin cables are ideal for low-power equipment such as battery chargers, stereo, and lights. If you plan to use it in power tools such as vacuum cleaners, saws, and drills, you will have to choose a thicker one. The 14-gauge is the thinnest we recommend at lengths of 25 feet or shorter.
A cord that can handle at least 15 amps
We recommend a cord that can handle at least 15 amps. Skip a cord that does not have a specification regarding its maximum capacity.
Most flexible cords are for cold weather
Some cords are more flexible in cold weather conditions. These are easier to stretch out and bend across your workspace, easy to keep and store, and flexible in tight spaces. When you’re at an electrical store, it is hard to determine if a cord is flexible without actually opening the package. The best way to ensure flexibility is by looking for one compatible with lower temperatures.
Skip multi-outlet ends for heavy-duty tools
It is tempting to get a multi-outlet extension cord because you can plug several tools into it. Getting one is fine if you plan to use it on light-duty equipment. For heavy-duty equipment, we do not recommend a multi-outlet cord because it is easier to overload.
For example, an extension can easily handle a circular saw. However, if you plug-in a few other tools into it, you might overload the plug, which could cause a meltdown or start a fire.
How can I tell which mine is?
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 that are 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 have an idea of 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.
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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. For a 6-gauge copper extension wire, it has a rating of 55 amps at an ambient temperature of 140°F, 65 at 167°F, and 75 at 194°F. Some thick extension cords are waterproof. It is best practice to check the specifications.
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. On the other hand, an 8-gauge copper extension wire rates at 40 amps at an ambient temperature of 140°F, 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, such as 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 for the user to pack it up.
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. On the other hand, a copper wire of the same AWG has a rating of 30 at 140°F, 35 at 167°F, and 40 at 194°F.
You can use a 10/3 with a ground wire for an apartment range, a large air conditioner, a built-in single oven, or an electric dry. 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.
A 12-gauge aluminum extension cord has a rating of 20 amps at 167°F and 25 at 194°F. On the other hand, a copper wire of the same AWG has a rating of 25 at 140°F, 25 at 167°F, and 30 at 194°F.
You can use a 12/3 cord in a variety of 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 starting a fire.
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.
A 16-gauge extension cord has a rating of 13 amps, which you can use for light-duty work. This type can only support devices that are not power-hungry. Using it with a space heater or any heat-generating appliance, such as clothes iron or toasters, is dangerous.
What do I need for 15 amps?
If you have a 15 amps appliance or tool, we recommend you use a 14-gauge copper wire. If it is unavailable, you can pick a larger diameters, such as a 12 or 10-gauge. When choosing the AWG size, you can get a bigger wire without worrying about compatibility issues.
Electrical safety: Do’s and Don’ts!
An extension cord is an electric wire which with multiple outlets on one end and a plug on the other. It is an important and necessary piece of equipment which 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 as well. Even though they are a handy piece of electric equipment to have in the house, they can be a fire hazard or a tangled mess that can lead to accidents. Each year around 3300 home fires are caused by the careless use.
The US Consumer Product Safety Commission reports that each year around 2000 injuries caused due to negligent use are reported in hospital emergency rooms. 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 through your home. Here’s how you can keep your family safe and tangle-free!
- 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 it 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 a 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.
- 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 actually 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, whether marked for outdoor or indoor use, should be stored in a dry place indoors when not in use.
- 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 in 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 and kitchens where water and electric flow are more likely to mix and 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 burnout.
- They should be kept away from areas with heavy footfall, incase of a trip and fall.
- Don’t bend or coil the wires when their plugged in.
- Do not nail any cord to the walls, ceilings or floors. In fact, 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. For instance, old hair dryers, faulty chargers and older lamp bulbs must be replaced and upgraded so that we may avoid accidents in case they burn out with excessive usage or faulty wiring issue.
When you buy any electrical equipment, its important to know its proper usage and terminology before you begin installation. 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 definitely rated for outdoor use. You can use them in your backyard, porch or front lawn without any worry of a 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 which are resistant to oil.
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.