Wire Gauge Chart
Every AWG and kcmil wire size this site's calculators use, in one table: NEC 310.16 ampacity at all three temperature columns for copper and aluminum, the breaker size NEC 240.4(D) actually allows, and the circuits each gauge typically shows up on.
| AWG / kcmil | Copper ampacity | Aluminum ampacity | Typical circuits | ||||
|---|---|---|---|---|---|---|---|
| 60°C | 75°C | 90°C | 60°C | 75°C | 90°C | ||
| 14 | 15 | 20 | 25 | — | — | — | 15 A lighting and general-purpose branch circuits, switch legs |
| 12 | 20 | 25 | 30 | 15 | 20 | 25 | 20 A receptacle, kitchen and bathroom counter circuits |
| 10 | 30 | 35 | 40 | 25 | 30 | 35 | 30 A circuits: electric dryers, window/through-wall AC, RV pedestals |
| 8 | 40 | 50 | 55 | 30 | 40 | 45 | 40-50 A circuits: ranges/cooktops, EV chargers, small subpanel feeders |
| 6 | 55 | 65 | 75 | 40 | 50 | 55 | 55-65 A circuits: ranges, hot tubs, AC/heat pump condensers, small subpanels |
| 4 | 70 | 85 | 95 | 55 | 65 | 75 | 70-85 A subpanel feeders, larger AC/heat pump condensers |
| 3 | 85 | 100 | 115 | 65 | 75 | 85 | 85-100 A feeders |
| 2 | 95 | 115 | 130 | 75 | 90 | 100 | 95-115 A feeders, larger subpanels |
| 1 | 110 | 130 | 145 | 85 | 100 | 115 | 110-130 A feeders |
| 1/0 | 125 | 150 | 170 | 100 | 120 | 135 | 125-150 A feeders, small services (aluminum is common here) |
| 2/0 | 145 | 175 | 195 | 115 | 135 | 150 | 145-175 A feeders |
| 3/0 | 165 | 200 | 225 | 130 | 155 | 175 | 165-200 A feeders; aluminum 3/0-4/0 is the common 200 A residential service drop |
| 4/0 | 195 | 230 | 260 | 150 | 180 | 205 | 195-230 A feeders; copper 4/0 is a common 200 A service entrance conductor |
| 250 kcmil | 215 | 255 | 290 | 170 | 205 | 230 | 215-255 A services and large feeders |
| 300 kcmil | 240 | 285 | 320 | 195 | 230 | 260 | 240-285 A commercial services and feeders |
| 350 kcmil | 260 | 310 | 350 | 210 | 250 | 280 | 260-310 A commercial services and feeders |
| 400 kcmil | 280 | 335 | 380 | 225 | 270 | 305 | 280-335 A commercial/industrial services and feeders |
| 500 kcmil | 320 | 380 | 430 | 260 | 310 | 350 | 320-380 A large commercial/industrial services and feeders |
75°C is bold because it's the column THHN/THWN-2 building wire uses with modern 75°C-rated equipment -- the everyday default. Source: NEC (NFPA 70) Table 310.16, 2026 edition (current as of this page, published September 2025); these ampacity values are unchanged from the 2020 and 2023 editions.
Not applied -- read this before using a number above
This chart is the NEC 310.16 base table only: 30°C (86°F) ambient, no more than three current-carrying conductors in the raceway or cable together. It does not apply:
- Ambient temperature correction (NEC 310.15(B)): a run through a hot attic or outdoors in summer derates every ampacity above, sometimes by 20% or more.
- Conductor bundling (NEC 310.15(C)): more than three current-carrying conductors together -- a multi-circuit homerun, for example -- also derates ampacity, separately from the temperature adjustment.
- Terminal temperature ratings (NEC 110.14(C)): even a 90°C-rated wire is limited to what the breaker or device it lands on is rated for, which is 60°C on most 15-30 A residential equipment.
- Voltage drop, conduit fill and box fill: three separate NEC checks on the same run, none of which this ampacity chart covers. See the voltage drop calculator, conduit fill chart and box fill calculator for those.
- Local amendments: your jurisdiction may have adopted an older or newer NEC edition, or amended it, and that local code governs over this national reference.
This chart is for general reference and planning only. It is not a substitute for a licensed electrician's judgment or for checking your actual, locally adopted electrical code, which can differ from the base NEC shown here and always governs. Real electrical work -- especially anything involving a panel, a feeder or a new circuit -- should be verified against that code and, in most places, requires a permit and a licensed electrician.
Frequently Asked Questions
Which ampacity column should I actually use -- 60, 75 or 90°C?
It depends on the insulation and the terminals, not on what you'd like the wire to carry. NM-B (Romex) is limited to the 60°C column by NEC 334.80 regardless of its 90°C-rated insulation. THHN/THWN-2 in conduit can use the 75°C column when the equipment it lands on -- breakers, receptacles -- is rated 75°C, which is standard for anything over 100 A and most modern gear; older or small (15-30 A) equipment is often only rated 60°C, per NEC 110.14(C), which pulls the whole circuit back to that column even with 90°C wire. The 90°C column itself is never the final ampacity for a general circuit -- it's an intermediate value used only in the temperature and bundling derating math of NEC 310.15(B)/(C).
Why does the chart start at 14 AWG?
14 AWG copper is the smallest conductor size in general use for branch circuits today and the range every calculator on this site is built around. The 2026 NEC (the newest edition, not yet locally adopted everywhere) added a 16 AWG copper row to Table 310.16 and lowered the code's general minimum conductor size from 14 to 16 AWG for certain listed uses, but that is a narrow, brand-new allowance, not general-purpose branch-circuit wiring, so it isn't in this chart.
Why is 12 AWG capped at a 20 A breaker when its 75°C ampacity is 25 A?
NEC 240.4(D): 14, 12 and 10 AWG copper get flat breaker caps of 15, 20 and 30 A regardless of their table ampacity, because those small-wire ratings assume ideal conditions residential wiring rarely gets. This is why the chart's "typical circuits" column for 12 AWG says 20 A, not 25 A.
Does a longer run change the wire gauge this chart implies?
Ampacity (this chart) and voltage drop are two separate checks on the same run, and a long run can force a larger gauge than ampacity alone requires even though the code doesn't mandate it outright. Use the voltage drop calculator to check a specific run length, or the wire size calculator to get both checks done together for one load.
Copper or aluminum for the same ampacity?
Aluminum needs roughly two gauges larger than copper for the same current -- an aluminum 2 AWG carries about what a copper 4 AWG does. It's common and code-compliant for service entrances and large feeders, where the cost saving is real, but it needs terminations and anti-oxidant compound rated for aluminum; branch circuits under 8 AWG are almost always copper.
Is this a substitute for checking my local code?
No. These are the national NEC 310.16 base ampacities at 30°C ambient with no more than three current-carrying conductors together -- more conductors bundled together, higher ambient temperature (an attic run in summer, for example), or a local amendment can all reduce the real allowable ampacity below what this chart shows. See the scope note under the chart for exactly what isn't modeled here.
These calculators use National Electrical Code tables and industry sizing charts and are for planning. They are not a substitute for a licensed electrician, an HVAC contractor's Manual J load calculation, or your local code, which governs. Electrical work can kill you and may require a permit; when in doubt, hire it out.