For 100 feet, match cord gauge to the tool’s amp draw: 16 AWG for 1–10 amps, 14 AWG for 11–13, 12 AWG for 14–15, and 10 AWG for 16–20 amps.
A single 16-gauge cord bought for a short run can overheat at 100 feet powering a circular saw. Length is the variable most people skip, and distance changes everything about the answer.
The chart below from the Electrical Safety Foundation International (ESFI) and Grainger shows what gauge fits each load at 100 feet. Verify your tool’s amp rating on its label, then match it to the correct wire size.
The 100-Foot Amp-to-Gauge Chart
Gauge drops as amps climb — meaning the wire must get thicker. The table below covers the full 1–20 amp range.
| Amp Draw | Gauge at 100 Ft | Typical Tools |
|---|---|---|
| 1–10 amps | 16 AWG | Work lights, fans, hedge trimmers, leaf blowers |
| 11–13 amps | 14 AWG | Lawn mowers, power drills, table saws |
| 14–15 amps | 12 AWG | Circular saws, shop vacs, refrigerators, miter saws, grinders |
| 16–20 amps | 10 AWG | Air compressors |
A cord that’s fine at 25 feet can be a fire risk stretched to 100.
Why Length Changes the Gauge You Need
A longer cord means more resistance, which drops voltage and generates heat. Too-light a gauge compounds both problems at once.
Voltage drop matters because motors and compressors draw more current to compensate for low voltage, which pushes the cord closer to its thermal limit. ESFI warns that assuming a short-distance cord is equally safe at 100 feet is a common and dangerous mistake.
Grainger’s guidance reinforces this: 16-gauge wire at 100 feet is limited to low-amp uses only. Plug a 15-amp circular saw into a 16-gauge 100-foot cord and you’re running a cord beyond its design load.
For most buyers, 12-gauge handles common 15-amp household tools, and 10-gauge covers heavier or continuous loads approaching 20 amps. If your tool sits near the top of its amp range — or runs for long stretches — size up rather than down.
Once you’ve matched your amp draw to a gauge, see the top-rated 10-gauge 100 ft cords we tested for heavier loads.
Common Mistakes That Overheat a 100-Foot Cord
Most failures trace back to one of three errors: wrong gauge, wrong assumption, or long high-draw runs.
- Buying a 16-gauge cord for a 15-amp tool because it worked fine at 25 feet.
- Assuming the amp rating on the tool is the only number that matters — cord gauge does too.
- Stretching a light-gauge cord to 100 feet for a circular saw, miter saw, or compressor.
- Ignoring the outdoor-rated jacket when the cord will sit on wet grass; look for SJTW.
Compatibility caveat: these charts apply to U.S. household AC use, commonly expressed for 120V/110V tool loads. Always check both the appliance nameplate and the cord’s printed amp rating before plugging in. The ESFI extension cord safety tips spell out the check-and-match process in full.
References & Sources
- Electrical Safety Foundation International. “Extension Cord Safety Tips.” Supports the amp-to-gauge chart and length-related safety warnings.
- Grainger. “Choosing the Right Extension Cord.” Supports gauge recommendations for 100-foot runs and tool examples.
- University of California Agriculture and Natural Resources. “Electrical Safety Notes.” Supports the one-gauge-per-100-feet rule of thumb.
