Extension cord sizing is not a guessing game. This is a beefy 12-gauge extension cord. This is the male end in my hand and the female end has a small glowing light in it when energized. Copyright 2018 Tim Carter
"Electricity encounters friction as it travels through electrical wires. Knowing this, use only as much extension cord as you really need. I can call you on the phone to answer your extension cord questions so you don't get KILLED or BURN DOWN YOUR HOME. The call is FREE if you're not satisfied with my answers. CLICK HERE to set up the call."
Extension Cord Sizing Checklist
- Determine amperage of tool/appliance
- Calculate cord length - use the shortest possible cord.
- Wire gauge determines amperage load
- Watts = Amps X Volts Example: 2,400 watts = 20 amps X 120 volts
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The size of your extension cord is very important. If you under-size one, you can start a fire or ruin an expensive tool.
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CLICK on my face to ensure you get the CORRECT extension cord so you or your family doesn't DIE IN A FIRE.
Fortunately, many common small hand-held electrical tools can operate without danger of motor damage when powered by a 16 gauge cord that is 100 feet long. To make sure you're properly protected, use the following sizing guidelines below.
CLICK or TAP HERE to get FREE ANSWERS from local electricians if you have extension cord questions.
How Do You Start to Size an Extension Cord?
You start to size an extension cord by obtaining the motor amperage from the plate on the tool. You'll find this information on the small metal plate where the serial number and model number is listed.
The green arrow points to the amperage of this professional circular saw. It shows 15A. That means 15 amps. Copyright 2018 Tim Carter
Usually, you will see an amperage rating. A tool may say it's rated for 8 amps. That's amperage.
What is Ohms Law?
Ohm's law is a physics principle that helps keep you safe with electricity. In it's simplest form, volts multiplied by amps equals watts.
This simple formula helps you to understand the sizing of extension cords because you may be required to convert an amp rating on a tool or appliance to watts.
Think about a light bulb. They're often sized by watts. The voltage in most circuits in USA homes is 120 volts. You may have a circuit breaker panel in your garage that has 15 or 20-amp breakers. All of these things concern Watt's Law.
If for some odd reason, you see watts listed instead of amps, you can convert watts to amps easily!
Here is how you do that: The formula for the conversion is:
Voltage x Amps = Watts
120 x 20 = 2,400
120 x 15 = 1,800
Because we use 120 volts as an electrical standard here in the USA, that means that every 600 watts equal 5 amps (120 x 5 = 600).
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What is Voltage Drop?
Voltage drop is the loss of voltage as it travels down a long wire.
Voltage drop is real. Electricity encounters resistance as it travels through electrical wires. Knowing this, use only as much extension cord as you really need. Resistance in the real world often creates friction which in turn almost always creates heat.
You can do your own simple experiment to demonstrate somewhat how this works. Use your one hand to rub your forearm back and forth. Go slowly at first and you may not feel much. Increase the speed of going back and forth and press down harder as you rub. That increased resistance will make your skin feel HOT for sure!
In other words, don't use a 100-foot cord for a project that is only 20 feet away. Purchase and maintain an assortment of different length cords.
Can I Have Multiple Tools On 1 Cord?
Yes, you can have multiple tools operating on one extension cord. You just have to be sure the cord is large enough to handle the loads.
I was guilty of this infraction many years ago before I fully understood all that's involved.
On construction sites, we'd commonly feed multiple saws and drills from one cord. If the circuit breaker at the panel is working fine, then you'll pop the breaker if there's a current overload.
But, if you've got a smaller-gauge extension cord, it's possible to overheat the cord and melt the insulation before the circuit breaker would trip!
However, if the breaker is bad you can either burn up the cord or damage tools from voltage drops. Use common sense.
How Do You Size an Extension Cord?
You size an extension cord by first determining the appliance or tool that will be plugged into the cord.
Determine the amperage of the tool(s) being used. Here is a handy list of some common electric power tools. The average amperage is listed below the tool. Always check on your tool label for its specific amperage.
Here are some COMMON amperage ratings of tools around your home:
- Circular saw: 12-15 amps
- Power drill: 3-7 amps
- Hedge Trimmer: 2-3 amps
- Weed Wacker: 2-4 amps
- Electric Chain Saw: 7-12 amps
- Leaf Blower: 6-12 amps
- Electric Lawn Mower: 6-12 amps
- Table Saw: 14-20 amps!
- Reciprocating Saw: 6-8 amps
- Router: 4-6 amps
Is the Length of the Cord Important?
Yes, the longer the cord is the greater the voltage drop will be. If you must go a distance greater than 100 feet, then upsize the extension cord.
Calculate the length of the cord you will need. Of course, you want to determine the maximum distance you think you will be from a permanent electrical outlet.
What Does Wire Gauge Mean?
Wire gauge is the measure of the diameter of the metal conductors in the extension cord. Common extension cord wire gauges are:
- 18
- 16
- 14
- 12
- 10
Use the following list to select the proper gauge extension cord. Remember, wire gauge refers to the thickness of the actual copper wire. As a wire gets thicker it can carry more electricity (amps). To confuse us, some idiot decided that as a wire gets thicker (bigger) the gauge number should get smaller!
The orange cord is only 18 gauge. Look how thin it is compared to the yellow cord that's 12-gauge. NOTE the 18-2 before the word TYPE in the red oval. That's how you know it's 18-gauge wire. Copyright 2018 Tim Carter
Here's what I mean. A 14-gauge wire can handle LESS current than a 12-gauge wire. The number 14 is bigger than 12. Confused? You should be!
What Load Can Each Gauge Wire Handle?
16-Gauge Cords: Any 16-gauge cord between 0 and 100 feet long will adequately handle tool loads up to 10 amps.
14-Gauge Cords: Any 14-gauge cord between 0 and 50 feet long will adequately handle loads between 10 and 15 amps.
12-Gauge Cords: If your tool load is between 10 and 15 amps and the length of the cord is 50 to 100 feet, you need a 12-gauge cord to safely power any tool.
This is a great extension cord for many purposes. CLICK THE IMAGE NOW to have it delivered to your home.
Why Does my Circuit Breaker Trip With the Right Cord?
Your circuit breaker may trip because the tool you're trying to power draws too much current. This is very common if you're trying to operate a large table saw cutting thick wood.
CAUTION: Most circuits in ordinary houses are wired with 14-gauge solid copper wire. This means in the circuit breaker panel you'll see a 15-amp breaker.
You may purchase a 12-gauge extension cord thinking that you'll be able to operate a powerful table saw but the breaker will probably trip when you load the saw. Remember, the circuit is rated for the SMALLEST SIZED cable or wire in the circuit.
CLICK or TAP HERE to get FREE ANSWERS from local electricians if you have extension cord questions.
Do Other Things on a Circuit Add to the Load?
Yes, other things, like a garage light, or some other appliance could be on the same circuit you've plugged the extension cord into. This adds to the total load on the circuit! You may think you have 15 amps available going to your extension cord, but several of those amps might be in use from something else.
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Article Name
Extension Cord Sizing | How to Get the Right Cord | AsktheBuilder.com
Description
Extension cord sizing is very important. A cord that's too small can cause a fire or ruin an expensive tool.
Author
Tim Carter
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AsktheBuilder.com
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FAQs
How do I know what size extension cord I need? ›
To select the right size gauge cord for your equipment, first identify the gauge on your equipment's power cord. This is typically engraved on the cord. Once you have identified the gauge of the cord on your equipment, you will need an extension cord that is at least one grade lower.
What are the different sizes of extension cords? ›Common household extension cords are available in 16 gauge (smallest), 14 gauge, 12 gauge, and 10 gauge (biggest). The lower the number, the bigger the gauge and the greater the amperage and wattage is.
Which is better 12 gauge or 14 gauge extension cord? ›For 100 feet, the 14 gauge cord works for 11-13 Amps, while the 12 gauge cord is best suited for 14-15 amps. If your cord is 150 feet long, the 14 gauge is best suited for 1-7 Amps, whereas the 12 gauge will support 8-10 Amps. This shows that the extension cord's length also plays a part in the power it helps safely.
Which is better 14 or 16 gauge extension cord? ›For blowers will 12 amps or less, use a 16-gauge light-duty cord within 50 feet of your outlet. Go with a 14-gauge medium-duty cord for a higher amp or a greater distance from the outlet. Make sure the cord is rated for outdoor use—look for a "W" on the jacket.
What is better 10 gauge or 12 gauge extension cord? ›Most devices will do fine with 12 gauge extension cords.
Power hungry devices such as lawnmowers, heavy machines, require a lower gauge such as 10AWG. Keep in mind, the lower the gauge means the thicker the cord.
The wire can never be too big, but it can be too small. Also, keep in mind that if you attach a multi-outlet device to an extension cord, allowing several tools to draw power at the same time, the current demand may exceed the amperage rating of the cord and create an unsafe condition.
Can a 12 gauge extension cord handle 20 amps? ›If you check the chart below, you will see that 12 AWG extension cord can handle up to 18 amps (25-feet and 50-feet cord), up to 15 amps (100-feet cord), and up to 10 amps (150-cord).
What does 14 AWG mean on an extension cord? ›Recommended wire gauge for extension cords
Larger numbers mean smaller wires, which in turn means it can carry less power. A cord measuring 14 AWG is the thinnest we recommend—and at lengths of only 25 feet or shorter—and the much thicker 10 AWG is likely the thickest gauge you'll find in an extension cord.
The lower the number, the higher the cord's capacity to deliver power. Gauge is typically listed along with the number of conducting wires in the cord. For example, a 14/3 cord contains 14-gauge wire and has three conductions inside. Extension cord lengths determine the cord's power capacity.
When should I use 12 gauge wire vs 14 gauge? ›Choosing Electrical Wire Size
14-gauge are usedfor light fixtures, lamps, lighting circuits with 15 amps. 12-gauge are used in kitchen, bathroom, outdoor receptacles, and 120-volt air conditioners supporting 20 amps.
How much can a 16 gauge extension cord handle? ›
For example, a 16 gauge extension cord less than 50 feet in length can power a 1625 watt (W) appliance. A 16 gauge cord that is longer than 50 feet in length can only power an appliance up to 1250W.
What is a 18 gauge extension cord used for? ›A serious exposure exists when light duty indoor rated 18 and 16-gauge (zip and ribbon style) cords are used. This ribbon extension cord is used around homes to plug in such devices as lamps, clocks, and other low voltage and low amperage rated devices up to 7 amps.
Can you connect a 12 gauge extension cord to a 14 gauge extension cord? ›A 14 ga cord has more resistance than 12 ga so putting them together increases the resistance to about 2.5X so that's bad. Safe to you and having the item work at 100 feet from the outlet are 2 VERY DIFFERENT THINGS.
How many watts can a 14 gauge extension cord handle? ›| Extension Cord Wire Gauges, Amperage Rating, and Wattage | ||
|---|---|---|
| Wire Gauge | Amperage Rating | Wattage Rating |
| #18 | 5 Amps | 600 Watts |
| #16 | 7 Amps | 840 Watts |
| #14 | 12 Amps | 1,440 Watts |
There is a risk that a circuit will fail and an electrical fire will occur if electrical current exceeds 20 amps. It is safe to use a 12 gauge extension cord with an input voltage of 20 amps. A 12 gauge wire should never carry an load of more than 30 amps.
What gauge extension cord for a refrigerator? ›3 Ft Appliance Extension Cord Heavy Duty, Gray - 14 Gauge 3 Prong SPT-3 Cable for Air Conditioner or Refrigerator.
Can a 10 gauge extension cord handle 30 amps? ›This seems to be the most common size RV and power on the market. Extension cords for 30A RV's are rated for 30 Amps at 125V. Almost all of the cables on the market will be 10 Gauge. You will have no problem running 30 Amps though these cords as well.
How do I know if my extension cord is overloaded? ›- If any part of the extension cord is hot while in use, it is a warning sign that it may be overloaded. Check if the extension cord is properly rated for the products that are plugged into it. ...
- Do not overload your extension cord by using it to power appliances beyond its capacity.
Power Strips
Larger appliances, such as microwaves and refrigerators, may not be plugged into a power strip or extension cord. Such appliances must be plugged directly into a properly installed outlet.
DON'T plug extensions cords together.
Get one that is the correct length you need. It may be tempting to just string them together, but resist the temptation. Extending the length of an extension cord by “daisy-chaining” can lead to overheating the cord by overloading it, creating a serious fire hazard.
What is better 12 gauge or 16 gauge extension cord? ›
The lower the number, the thicker the wire, or bundle of wire, and the thicker the wire, the more watts you can expect to power through it. So a 10-12 gauge cord would be a heavier duty cord than a 16-gauge cord, which would be a lightweight cord typically used for less energy demanding applications.
How many amps is 12 gauge rated for? ›RULES OF THUMB
“Twelve-gauge wire is good for 20 amps, 10-gauge wire is good for 30 amps, 8-gauge is good for 40 amps, and 6-gauge is good for 55 amps,” and “The circuit breaker or fuse is always sized to protect the conductor [wire].”
16ga steel is . 065” inches thick, that is about 1/16th of an inch thick. 14 gauge in comparison is . 083 inches thick which doesn't sound like much except it is almost 30% thicker (27.6% to be exact).
Which is thicker 14 AWG or 18 AWG? ›Speaker Wire Gauge
The thicker the wire the lower the gauge number & the thinner the wire the higher the gauge number or AWG. For example, a 12 AWG is thicker than an 18 AWG wire. The most common audio speaker wires are 12 Gauge, 14 Gauge, 16 Gauge, and 18 Gauge.
Q: How many watts can a 13 amp socket take? A: Plugging in 4 items such as a TV, DVD player, Sky Box and games console to an extension , would amount to just over 750 watts = 3 Amps. It is important to never overload a plug socket, which is 3000 watts = 13 Amps. Some appliances use more than others.
What is the difference between extension cord 16 3 and 12 3? ›The most common size outdoor extension cords are 16-3, 14-3 and 12-3. For light uses on small power tools the 16-3 is fine but for higher ampere tools such as a table saw, 12-3 is recommended.
What does 16 2 extension cord mean? ›A 16/2 cord means the wire thickness is 16-gauge, and each plug has 2-prongs. 10A rating at 125V, 16/2-gauge, SJTW(rated weatherproof). Commonly used for appliances, electric grills, decorative lighting, holiday lighting, and outdoor applications.
What does 12 AWG mean on an extension cord? ›16 gauge=light duty. 14 gauge=medium duty. 12 gauge=heavy duty. 10 gauge=very heavy duty.
What happens if I use the wrong gauge extension cord? ›Using an extension cord with too small a gauge of wire for the current draw will cause the wire and cord to heat up! This can lead to melting of receptacles, damage to your electrical device (and could potentially cause an electrical fire).
How far can you run 10 gauge extension cord? ›Longer cords always experience a significant power drop. Therefore, while a 25-foot 10 gauge extension cord can easily handle up to 20 amps, a 150-foot 10 gauge cord can only go up to 15 amps.
How many amps can a 8 gauge extension cord handle? ›
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.
Can I use 14 gauge wire for lights on a 20 amp circuit? ›You cannot use any 14 gauge wire on a 20 amp circuit. This is true, even running to a light fixture that has smaller wires built in. The wires built into the fixture are allowed as part of a manufactured assembly. However, any added wire must be appropriate to the circuit breaker protecting the wire.
How many outlets can you run on 14 2 wire? ›14/2 wire can be used for outlets and lights with a 15-amps circuit. Each light is usually of one amp, thus you can use 14/2 wire to 12 outlets which are protected by a 15-amp breaker.
How many outlets can you have on a 15 amp circuit? ›Therefore, you can have 25 outlets on a 15-amp circuit as long as you aren't drawing more than 12 amps through that circuit at any given time. On a conventional 120-volt circuit, this translates to 1,440 watts, even though the breaker can handle up to 1,800 watts and won't trip until you exceed that amount.
How many amps is a 16-gauge wire? ›- Uses: lamps, clocks, and other light-duty electrical devices drawing up to 7 amps.
- Cord length up to 25 feet: use 18 AWG wire.
- Cord length up to 50 feet: use 16 AWG wire.
- Cord length up to 100 feet: use 14 AWG wire.
If the extension cord is 25 feet or shorter, use a 16-gauge cord. If the cord is longer, you should select a heavier-duty 14-gauge cord to connect your holiday lights.
What is the difference between 16 3 and 12 3 extension cord? ›The most common size outdoor extension cords are 16-3, 14-3 and 12-3. For light uses on small power tools the 16-3 is fine but for higher ampere tools such as a table saw, 12-3 is recommended.
What does a 14 gauge extension cord mean? ›Recommended wire gauge for extension cords
Larger numbers mean smaller wires, which in turn means it can carry less power. A cord measuring 14 AWG is the thinnest we recommend—and at lengths of only 25 feet or shorter—and the much thicker 10 AWG is likely the thickest gauge you'll find in an extension cord.
Don't exceed load
The average extension cord is rated at 1250 watts, but many heaters go up to 1500 watts. The average extension cord could easily overheat when used with a 1500-watt heater. Faulty extension cords cause 7,400 home fires in the U.S. annually, causing 80 deaths and 260 injuries.
How many amps can a 16 gauge 100 ft extension cord handle? ›
16 gauge for up to 10 amps; 14 gauge for up to 13 amps; 12 gauge for up to 15 amps; 10 gauge for up to 20 amps.
Can I use a 14 gauge extension cord on a 20 amp circuit? ›NO. 14 gauge is prohibited from use in any section of a 20 amp circuit. You need to use 12 gauge wire for 20 amp circuits. This is for safety reasons.
What is considered a heavy gauge extension cord? ›A 10- to 12-gauge cord is for heavy and extra heavy duty applications (chainsaws, circular saws, shop vacs, air compressors, etc.). These are the heavier weight, and heavier duty cords designed for continual use on job sites, even in extreme weather, and are suitable for very high-amperage tools.