The Best Extension Cords for Indoor and Outdoor Use
Swap out potentially dangerous extension cords with quality replacements in the right lengths, ratings, and materials for use just about anywhere.
An extension cord—insulated wire with a plug at one end and a socket at the other—comes in handy whenever you need to connect an appliance, power tool, or other electrical device to a power source beyond the reach of the device’s own cord.
Helpful as they are, extension cords can be dangerous. According to the Electric Safety Foundation International (ESFI), about 3,300 home fires are started annually by extension cords, killing or injuring hundreds of people each year. The reason for these fires is overheated wires—meaning, too much electrical current passing through wires that are inadequate for the job.
Knowing this, you may be inclined to replace old extension cords with new ones that can keep you and your home safe. So read on to learn how to select the right products for use indoors and out—and to find out why we’ve chosen the below as the best extension cord options out there today:
- BEST ALL AROUND: Iron Forge Cable Lighted Outlet Indoor/Outdoor 100-Foot Extension Cord
- BEST FOR LIGHT DUTY: FIRMERST 1875W Flat Plug 1Ft Extension Cord
- BEST FOR HEAVY DUTY: US Wire and Cable 99050 Extension Cord, 50ft
- BEST FOR OUTDOORS: UltraPro, GE 25 ft Extension, 3 Outlet, Grounded, Double Insulated Cord
- BEST DESIGN: Cordinate, Designer 3 Extension Cord, 2 Prong Power Strip, Extra Long 8 Ft Cable
6 Things to Know Before You Shop
Half a dozen different factors contribute to an extension cord’s electrical current bandwidth and range of use—gauge rating, power rating (in amps/volts/watts), cord length and voltage drop, jacket strength, plug and socket type, and intended use. In addition, you may want to weigh peripheral considerations like aesthetic appeal and usability features (for instance, lighted plug ends).
1. Gauge Rating
Wire gauge is the thickness or diameter of an extension cord’s internal wire. This thickness is measured by an American Wire Gauge (AWG) number: the smaller the number (000 to 40), the thicker the wire. For most home and outdoor use, look for a gauge rating between 10 and 18 AWG. You can typically find a cord’s AWG number (also called a gauge rating) on the cord’s outer jacket—that’s the layer of thermoplastic that surrounds and protects the electrical wires (see Jacket Strength, below). The gauge rating is usually paired with the number of conducting wires inside the cord. For example, a 16/3 cord means 16-gauge wire with three wires inside.
2. Power Rating
In addition to the gauge rating, you’ll often see three numbers associated with an extension cord’s power capacity: amps/volts/watts. Amperes (amps) measure the volume or amount of electricity flowing through a conductor (e.g., the wire inside the cord). Voltage (volts) measures the pressure or resistance of this electric flow. Watts measure the resulting power (volts times amps). These numbers are crucial because a cord can overheat and catch fire by plugging a high-wattage appliance into a cord with an insufficient power rating.
3. Cord Length and Voltage Drop
While some extension cords may be longer than 100 feet, those between 1 and 100 feet are the most helpful and popular for tasks in and around the home. Cord length also affects how much voltage is lost due to electrical resistance over distance—the longer the extension cord, the greater the voltage lost, a property called “voltage drop.” To avoid voltage drop, use the shortest extension cord possible for a given task. Longer cords have less capacity (greater voltage drop) than shorter cords with the same gauge rating. For example, a 16-gauge extension cord that’s less than 50 feet long can power an appliance up to 1625 watts, while a 16-gauge cord that’s longer than 50 feet will have less wattage and only power a 1250W appliance.
4. Jacket Strength
Wire is an excellent conductor, but to function safely and effectively, it needs insulation, also known as a jacket. Plastic or woven nylon are used to cover indoor extension cords, while heavy-duty plastics, rubber, and vinyl are often used to coat the electrical wires in outdoor extension cords. This protects the wire from environmental exposure, electrical leakage, and overheating.
The strength, material, and purpose of the cord jacket are designated by different letters. You will often see a combination of these letters printed on the jacket itself. Here are the most common letters associated with household and outdoor extension cords:
- S – Indicates a flexible cord designed for general use
- W – Indicates the cord is rated for outdoor use
- J – Indicates a cord with standard 300 voltage insulation. If there is no J in the designation, the cord has thicker, 600-volt insulation, designed for heavier use.
- P – Indicates parallel wire construction, used in air conditioner cords and household extension cords
- T – Indicates the cord jacket is made from vinyl thermoplastic
- E – Indicates the cord jacket is made from thermoplastic elastomer rubber (TPE)
- O – Indicates the cord is oil-resistant
5. Intended Use and Safety
The main distinction between extension cords is between indoor and general/outdoor use. General use and outdoor cords can be used indoors, but never use an indoor extension cord outdoors. Once you decide between indoor and general/outdoor use, you will need to consider other choices. For instance, the environment your cord will be exposed to is very important. More extreme temperatures require heavier-duty jacket materials. Finally, you’ll need to think about how often your cord will be used, and with what appliances.
- Light-duty cords can range from 25 to 100 feet, with a one to 13 amp power rating, and 16-gauge wire. These cords are good for Christmas lights, fans, and hedge trimmers.
- Medium-duty cords can range from 25 to 150 feet, with a 14 to 15 amp power rating, and 14-gauge wire; useful for powering lawn mowers and power drills.
- Heavy-/rugged-duty cords can range from 25 to 150 feet, with a 16 to 20 amp power rating, and 10- or 12-gauge wire. These are designed for chain saws, shop vacs, and power-hungry tools and generators.
Many reliable extension cords also have a safety rating, certified by an independent testing agency, such as Underwriters Laboratories (UL), Intertek (ETL) or the Canadian Standards Association (CSA), to ensure the cord meets federal and international safety standards.
6. Plug and Socket Type
An extension cord plug may have two or three prongs. The third prong means that the cord is “grounded,” providing an additional path for electrical currents and contributing to overall safety. The ground pin (third prong) is an essential safety feature of heavier duty extension cords and should never be removed or bypassed in any way. Grounded (three-pronged) extension cords should be used with larger appliances.
The socket is the part of the extension cord into which you plug your appliances. This strip may contain multiple sockets (for two- or three-prong plugs), allowing you to power up multiple appliances, provided you don’t go over the wattage (power rating) on the cord’s label. Note that a two-pronged plug may be inserted into a three-slotted socket, but never the reverse. Also, always use an extension cord with three-pronged sockets with appliances that have three-pronged plug ends.
Several standout features may contribute to cord usefulness and safety, and if your extension cord is intended for indoor use, its appearance may play a role in your decision. Additional features include:
- Built-In Ground Fault Circuit Interrupter (GFCI) is a safety measure device that automatically shuts down power to the extension cord in the event of a ground fault or short circuit.
- Lighted plug ends illuminate to indicate when the cord is powered. It is also a safety feature of outdoor extension cords, for use in darker conditions.
- A connector box fits around both the extension cord plug and the plug on the connected electrical device to keep them from pulling apart.
- A locking socket is a mechanism built into the extension cord socket that keeps the device and cord securely connected.
The Best (and Safest) Extension Cords
1. BEST ALL AROUND: Iron Forge Cable Lighted Outlet Indoor/Outdoor 100-Foot Extension Cord
Iron Forge’s all-purpose extension cords, designed for both indoor and outdoor use, have a flexible vinyl jacket that’s water-resistant and protects against moisture, abrasion, and sunlight. The 12-gauge wire has a power rating of 15 amps/125 volts/1875 watts, and the cords are UL listed for safety. The light socket is illumined by LED bulbs to indicate when the power is on, and the plug has reinforced blades to prevent bending or breaking. From running a lawn mower to powering holiday string lights, these extension cords can handle most medium to heavy-duty devices, and you can choose the best length for the job, from 6 to 200 feet.
2. BEST FOR LIGHT DUTY: FIRMERST 1875W Flat Plug 1Ft Extension Cord
Firmerst’s 1-foot extension cords have a 14 AWG gauge rating and a power capacity of 15 amps/125 volts/1875 watts. These thicker wires can handle more amperage and wattage, with less chance of overheating, than similar competing products with 16 or 18 AWG wires. Meaning that, for a short extension cord, the Firmerst can handle more current than you might expect. Temperature resistant up to 75 degrees Celsius (167 degrees Fahrenheit), these cords are UL certified, wrapped in heavy-duty plastic, and feature a flat plug design well suited for the tight space between outlets and furniture.
3. BEST FOR HEAVY DUTY: US Wire and Cable 99050 Extension Cord, 50ft
This highly versatile outdoor extension cord has an insulating jacket made of 100 percent thermo-plastic elastometer (TPR), a compound that provides maximum flexibility in extreme temps, between 221°F (105°C) and -94°F (-70°C). The jacket is also oil-resistant and more durable than standard PVC cords in harsh environments. Choose between a 12- or 14-gauge rating, and three lengths: 25, 50, and 100 feet. Featuring lighted plug ends for safety and visibility in darker conditions, and with a 15-amp power capacity, this cord is designed for medium to heavy-duty outdoor use, including power tools and snow blowers.
4. BEST FOR OUTDOORS: UltraPro, GE 25 ft Extension, 3 Outlet, Grounded, Double Insulated Cord
GE’s extension cords are available in 15-, 25-, and 40-foot lengths, so you can pick the size that suits your appliance (wattage) needs and the area you’ll need to cover. The 25-foot cord has a 13 amps/125 volts/1625 watts power capacity that’s ideal for outdoor lighting, and it’s double insulated for durability and longevity. In other words, this UL-listed cord with three power outlets is sure to safely and reliably meet your outdoor power-extending needs. The cords come in black (easy to conceal) and bright orange (highly visible for added safety).
Let’s face it: Extension cords aren’t pretty. Fortunately, the Cordinate cord is an exception. Instead of a thick plastic jacket, the eight-foot cord is wrapped in woven fabric to blend in with its surroundings while preventing bends and tangles. Choose from 15 different colors and chevron-patterned designs. With three polarized outlets and a space-saving flat, two-prong power strip, this extension cord is ideal for lamps, fans, and small household appliances (its power capacity is 13 amps/125 volts/1625 watts). For extra safety and to prevent electrical shocks, the cord includes slide-to-lock covers for each outlet.