For standard residential branch circuits in the US, the most queried AWG wire chart amps values based on the 60°C column (which governs most non-metallic sheathed cables like NM-B/Romex) are: 14 AWG = 15A, 12 AWG = 20A, 10 AWG = 30A, 8 AWG = 40A, and 6 AWG = 55A. However, blindly pulling a number from a chart without understanding temperature columns and NEC 240.4(D) overcurrent limits is how you end up with a melted terminal lug or a failed inspection. This reference gives you the exact numbers, the rules that modify them, and a concrete decision path for your next pull.
How to Read the AWG Wire Chart Amps Table
The ampacity table below is sourced directly from NFPA 70 (National Electrical Code) Table 310.16. Before you pick a row, you must understand the three temperature columns (60°C, 75°C, and 90°C) and the 'weakest link' rule.
Furthermore, NEC 240.4(D) places hard caps on small conductors for overcurrent protection. Regardless of what the 75°C or 90°C columns say, 14 AWG copper is capped at a 15A breaker, 12 AWG at 20A, and 10 AWG at 30A, unless specific motor or HVAC exceptions apply.
Complete NEC 310.16 Ampacity Table (Copper)
Use the anchor links below to jump to the most commonly queried residential sizes. This table assumes copper conductors, an ambient temperature of 30°C (86°F), and not more than three current-carrying conductors in a raceway or cable.
| AWG Size | 60°C (140°F) NM-B / Romex |
75°C (167°F) THHN Terminations |
90°C (194°F) Derating Baseline |
Max Standard Breaker (NEC 240.4) |
|---|---|---|---|---|
| 14 AWG | 15A | 20A | 25A | 15A |
| 12 AWG | 20A | 25A | 30A | 20A |
| 10 AWG | 30A | 35A | 40A | 30A |
| 8 AWG | 40A | 50A | 55A | 40A / 50A* |
| 6 AWG | 55A | 65A | 75A | 60A |
| 4 AWG | 70A | 85A | 95A | 80A |
| 3 AWG | 85A | 100A | 115A | 100A |
| 2 AWG | 95A | 115A | 130A | 125A |
| 1 AWG | 110A | 130A | 145A | 150A |
| 1/0 AWG | 125A | 150A | 170A | 150A |
| 2/0 AWG | 145A | 175A | 195A | 175A |
| 3/0 AWG | 165A | 200A | 225A | 200A |
| 4/0 AWG | 195A | 230A | 260A | 225A / 250A |
*Note: 8 AWG is limited to 40A under 240.4(D) for general use, but 50A is permitted for specific applications like electric ranges or HVAC per NEC 240.4(G) and 310.15.
Decision Path: Picking Your Wire and Breaker
Stop guessing. Match your specific installation scenario to the table below to get a concrete wire gauge, temperature column, and breaker size. This path assumes standard residential 120V/240V copper wiring.
| Installation Scenario | Max Continuous Load | Concrete Wire Pick & Column | Concrete Breaker Pick |
|---|---|---|---|
| Standard 15A Bedroom/Living Room Receptacles | 12A | 14 AWG NM-B (60°C column) | 15A Standard |
| Kitchen Small Appliance or Bathroom GFCI | 16A | 12 AWG NM-B (60°C column) | 20A Standard |
| 30A Electric Dryer or RV Outlet (120/240V) | 24A | 10 AWG NM-B (60°C) OR 10 AWG THHN in conduit (75°C) | 30A Standard |
| 40A Hardwired EV Charger (Level 2) | 32A (80% rule) | 8 AWG THHN in conduit (75°C column at terminations) | 40A Standard |
| 50A Electric Range or 50A EVSE | 40A (80% rule) | 6 AWG NM-B (60°C) OR 8 AWG THHN in conduit (75°C) | 50A Standard |
| 100A Subpanel Feeder (Short run) | 80A | 3 AWG THHN in conduit (75°C column) | 100A Standard |
Derating: When the Base Chart Isn't Enough
The numbers in the chart above assume perfect conditions: an ambient temperature of 30°C (86°F) and no more than three current-carrying conductors (CCCs) bundled together. When you exceed these parameters, you must apply derating factors to the 90°C column (even if your terminations are 75°C) to ensure the wire insulation doesn't melt inside the conduit.
Scenario: Bundling in Conduit
Imagine you are pulling four current-carrying conductors (e.g., two 120V circuits sharing a neutral, plus a ground) through a single EMT conduit for a multi-wire branch circuit. You are using 12 AWG THHN.
- Start at the 90°C column: 12 AWG THHN at 90°C is rated for 30A.
- Find the adjustment factor: NEC Table 310.15(C)(1) states that 4 to 6 current-carrying conductors require an 80% adjustment factor.
- Do the math: 30A × 0.80 = 24A derated ampacity.
- Apply the termination limit: Your breaker and devices are rated 75°C. The 75°C column for 12 AWG is 25A. Since your derated 90°C value (24A) is lower than the 75°C termination limit (25A), 24A becomes your final allowable ampacity.
- Final Pick: 24A is greater than your 20A load, and per 240.4(D), you can protect 12 AWG with a 20A breaker. The installation is code-compliant.
Scenario: High Ambient Temperature
If that same conduit runs across an attic where the ambient temperature hits 110°F (43°C), you must also apply the temperature correction factor from the bottom of Table 310.16. For 90°C wire at 110°F, the factor is 0.87. You multiply the base 90°C ampacity by both the bundling factor and the temperature factor. If the final calculated number drops below your breaker size, you must upsize the wire.
What This Chart Cannot Tell You
While the Copper Development Association and the NEC provide the baseline thermal limits for wire, an ampacity chart is blind to three critical real-world factors:
- Voltage Drop: Table 310.16 does not account for distance. If you are running a 20A circuit to a detached garage 150 feet away, 12 AWG wire will experience a voltage drop exceeding the recommended 3% threshold. You must upsize to 10 AWG or 8 AWG purely to maintain voltage, even though 12 AWG is thermally sufficient for 20A.
- Physical Conduit Fill: The chart tells you the wire can handle the current, but it doesn't tell you if the wire will physically fit. NEC Chapter 9, Table 1 limits conduit fill to 40% for three or more wires. Upsizing wire for voltage drop might require you to simultaneously upsize your conduit diameter.
- Local AHJ Amendments: The NEC is a model code. Your local Authority Having Jurisdiction (AHJ) may have amendments that override these tables. Some municipalities mandate 12 AWG as the absolute minimum for all 15A and 20A receptacle circuits, effectively banning 14 AWG from residential construction entirely.
Use the 60°C column for all NM-B cable runs, default to the 75°C column for THHN terminations on standard breakers, and always run the derating math if you are pulling more than three wires in a pipe. Secure your permits, torque your lugs to the manufacturer's spec, and let your local inspector make the final call.
