Appliance Amp Draw → Minimum Cord Gauge
Instead of starting from a wire gauge, start from what you're plugging in. This table maps six common high-draw loads — space heater, air compressor, table saw, welder, portable generator, and RV shore power — to their typical amp draw and the minimum safe cord gauge at 25, 50, 100, and 150 feet, derived directly from the Cord Gauge Ampacity Index.
⚠ Safety notice: treat every gauge below as a floor, not a target — size up one gauge if in doubt. This is general reference, not an electrical code determination; local code governs, and permanent/hardwired circuits require a licensed electrician.
License: CC BY 4.0 — free to use with attribution.
The table
| Appliance / tool | Typical draw | Min. gauge @25ft | @50ft | @100ft | @150ft |
|---|---|---|---|---|---|
| Space heater (1500W, 120V) Manufacturer nameplate rating (typical 1500W/120V portable space heater) (manufacturer spec) | 12.5A | 16 AWG | 14 AWG | 10 AWG | 8 AWG |
| Air compressor, portable (120V, 15A-rated) Manufacturer nameplate rating (typical portable 120V shop compressor, running load) (manufacturer spec) | 12.0A | 16 AWG | 14 AWG | 10 AWG | 10 AWG |
| Table saw / benchtop tool (120V, 15A motor) Manufacturer nameplate rating (typical 120V benchtop/contractor table saw) (manufacturer spec) | 15.0A | 14 AWG | 12 AWG | 10 AWG | 8 AWG |
| Wire-feed/stick welder (120V input) Manufacturer nameplate rating (typical 120V MIG/stick welder input current) (manufacturer spec) | 20.0A | 12 AWG | 12 AWG | 8 AWG | 6 AWG |
| Portable generator output (30A twist-lock) Standard NEMA L5-30/L14-30 30A generator receptacle rating (NEC/UL reference) | 30.0A | 8 AWG | 8 AWG | 6 AWG | 6 AWG |
| RV shore power (30A service) Standard 30A RV shore-power (TT-30) receptacle rating (NEC/UL reference) | 30.0A | 8 AWG | 8 AWG | 6 AWG | 6 AWG |
How these minimums were derived
For each appliance's typical amp draw, we found the thinnest gauge in the Cord Gauge Ampacity Index whose max-safe-continuous-amps at that length still meets or exceeds the draw. Generator and RV shore-power rows use the standard NEMA receptacle rating (30A) rather than an estimate, since that's the number the equipment is built and sold around. All figures inherit the same conservative, round-down-and-take-the-lower-limit policy as the Ampacity Index.
Caveats
- These are floors, not targets. Real nameplate draw varies by specific model — always check YOUR appliance's actual rated amps or watts (watts ÷ volts = amps) rather than assuming the typical figure here.
- Startup/surge current is not modeled. Motors (compressors, table saws) draw more at startup than at steady run — this table uses running/steady-state draw, consistent with standard cord-sizing practice, not surge current.
- Connector type is a separate decision from gauge. A generator's 30A twist-lock (L5-30/L14-30) plug will not fit a household outlet cord regardless of gauge — see What Gauge Extension Cord for a Generator?.
- This is general reference, not a code determination for your specific equipment or circuit.
Methodology & versioning
Version 1.0 — published July 30, 2026. Derived from the Cord Gauge Ampacity Index (see that page's methodology for the underlying thermal/voltage-drop calculation). Appliance draw figures are typical manufacturer nameplate values for common consumer-grade equipment in each category, cross-checked against published spec sheets; generator/RV figures use the fixed NEMA receptacle amperage. Corrections: if a figure changes or we find an error, this page and both CSVs are updated in place and the version/date bumped.
Machine-readable download: /appliance-amp-draw-to-gauge.csv (always latest) and the version-pinned /appliance-amp-draw-to-gauge-v1.0.csv.
How to cite
Cord Gauge Decoded, "Appliance Amp Draw to Gauge" v1.0 (2026). https://cordgauge-decoded.pages.dev/appliance-amp-draw-to-gauge/. Licensed CC BY 4.0.
Frequently Asked Questions
A companion dataset to the Cord Gauge Ampacity Index. Instead of starting from a wire gauge, it starts from a specific appliance or tool's typical amp draw and works backward to the MINIMUM cord gauge that stays within safe voltage drop and thermal limits at 25, 50, 100, and 150 feet.
Because voltage drop accumulates with length. A space heater that's safe on a thin 16 AWG cord at 25ft needs a much heavier 8 AWG cord at 150ft to keep the same appliance's voltage drop within a safe range — the appliance's draw never changes, but the cord's resistance over that distance does.
No — treat these as a floor, not a target. If in doubt, size up one gauge, especially for continuous, safety-relevant, or high-heat loads (generators, welders, heaters running unattended). We deliberately rounded toward the safer, lower-amperage side when building this table.
No — welders and generator/RV shore power draw considerably more current and are cross-referenced against our Cord Gauge Ampacity Index using their standard rated amperage (e.g. the NEMA 30A twist-lock rating), not an estimate. Always match connector type as well as gauge — see our generator and welder cord guides.