The first extension cord I bought for my circular saw came in a hardware store bin labeled 100 feet for 20 dollars. The first cut overheated the cord and the motor bogged badly. I replaced it with a proper 12 gauge cord and the saw cut like a different tool. Gauge is the spec that matters and almost nobody reads it.
| Product | Gauge | Length |
|---|---|---|
| Iron Forge Cable 12 AWG | 12 AWG | 50 feet |
| US Wire 100 Foot 12 Gauge | 12 AWG | 100 feet |
| GE 14 Gauge Outdoor Cord | 14 AWG | 25 feet |
| Yellow Jacket 10 Gauge | 10 AWG | 50 feet |
| Cordinate 16 Gauge Light Duty | 16 AWG | 9 feet |
Match Gauge to Amperage and Length
Lower AWG number means thicker wire. A 14 gauge cord handles 15 amps at 25 feet, but at 100 feet it drops voltage enough to harm motors. For most outdoor power tools, 12 gauge is the answer at any length up to 100 feet. For pressure washers and tile saws pulling close to 15 amps, step up to 10 gauge once you go past 50 feet. The math is simple but the bin at the hardware store does not explain it.
For Long Runs, Buy Once
A 100 foot 12 gauge cord costs about 80 dollars and lasts a decade with normal care. The U S Wire branded model has a thick jacket that resists scrapes against deck boards and concrete. I have run a circular saw, a chainsaw, and a 1800 PSI pressure washer through the same cord for five years without any heat issues. Coiling it loosely after each use keeps the copper from work hardening at the bends.
Short Cords for Yard Work
For blowers, string trimmers, and small drills under 10 amps, a 25 foot 14 gauge cord is enough. The GE branded version is cheap, has lighted ends so you can see if power is live, and folds into a five gallon bucket for storage. Do not chain two of these end to end because voltage drop compounds fast across connections.
When You Actually Need 10 Gauge
The 10 gauge cord is for compressors, welders, and large pressure washers that pull 15 amps for sustained periods. A Yellow Jacket 10 gauge feels heavy in your hand and it should. I bought one when I started running a 240 volt portable air compressor and the difference in motor start up was obvious. If your tool nameplate says 13 amps or more and the run is over 50 feet, you need this gauge.
Light Duty Cords Have Their Place
A 9 foot 16 gauge cord is fine for plugging in a phone charger or a small fan on a porch. Do not use it for any tool with a motor. The wire is too thin and the cord will get warm under load. Keep one in a kitchen drawer and never confuse it with the tool cord coiled in your garage.
How to Choose
Read the amperage on the tool nameplate first. Then pick gauge based on length: 14 gauge for 25 feet of light work, 12 gauge for 50 to 100 feet of medium duty, and 10 gauge for anything above 13 amps at distance. Always pick an SJTW or W rated cord for outdoors. Inspect cords yearly for jacket cracks because the copper inside oxidizes and resistance climbs.
Frequently asked questions
What gauge cord do I need for a 15 amp tool at 100 feet?+
Use 12 gauge or heavier. A 14 gauge cord at that length will drop too much voltage and your motor will run hot and underpowered.
Are all outdoor cords safe in wet weather?+
Only cords marked W or SJTW are rated for wet conditions. Indoor cords marked SJT are not safe outside even on a dry day if there is a chance of rain.