Stop hunting for a downloadable wire gauge chart pdf. You are looking at it. This page contains the exact data found in NEC Table 310.16 for copper conductors, formatted for quick reference on your phone or tablet while you are standing in front of an open panel or pulling wire through conduit. Bookmark this page, or use your browser's 'Print to PDF' function to save it locally.
How to read this table: The rows represent American Wire Gauge (AWG) sizes, progressing from smallest (14 AWG) to largest (4/0 AWG). The columns represent the allowable ampacity based on the insulation's temperature rating (60°C, 75°C, and 90°C). The final column lists the maximum standard overcurrent protection device (breaker or fuse) size permitted by NEC 240.4(B), assuming the calculated load does not exceed the wire's ampacity. All values assume an ambient temperature of 30°C (86°F) and no more than three current-carrying conductors in a raceway.
Quick Jump: 14 AWG | 12 AWG | 10 AWG | 8 AWG | 6 AWG
The Master NEC Wire Gauge & Ampacity Table (Copper)
The following data is sourced directly from the NFPA National Electrical Code (NEC) Table 310.16. This table applies strictly to copper conductors. If you are using aluminum, you must use a separate table, as aluminum has lower ampacity for the same physical gauge.
| AWG Size | 60°C (140°F) Ampacity |
75°C (167°F) Ampacity |
90°C (194°F) Ampacity |
Max Standard Breaker (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 | 50A |
| 6 AWG | 55A | 65A | 75A | 70A |
| 4 AWG | 70A | 85A | 95A | 90A |
| 3 AWG | 85A | 100A | 115A | 110A |
| 2 AWG | 95A | 115A | 130A | 125A |
| 1 AWG | 110A | 130A | 145A | 150A |
| 1/0 AWG | 125A | 150A | 170A | 175A |
| 2/0 AWG | 145A | 175A | 195A | 200A |
| 3/0 AWG | 165A | 200A | 225A | 225A |
| 4/0 AWG | 195A | 230A | 260A | 250A |
Which Column Applies to Your Installation?
The most common mistake DIYers and junior apprentices make when reading a wire gauge chart pdf is blindly using the 90°C column because it offers the highest ampacity. In residential and light commercial wiring, you will almost never use the 90°C column for your final breaker sizing. Here is how to select the correct column based on the Electrical Contractor Magazine (ECMAG) Codes & Standards interpretations of NEC 110.14(C).
The 60°C Column: Your Default for Small Branch Circuits
Use the 60°C column for circuits rated 100 amps or less, and for wire sizes 14 AWG through 1 AWG. Why? Because standard residential receptacles, switches, and small breakers are typically only tested and rated for 60°C terminations. Even if you pull 12 AWG THHN (which has 90°C insulation) through your conduit, the moment it lands on a standard 15A or 20A duplex receptacle, the termination point is the weak link. You must size the wire based on the lowest temperature rating in the entire circuit. Furthermore, standard NM-B (Romex) cable is strictly limited to the 60°C ampacity column by NEC 334.80, regardless of the 90°C rating of the individual conductors inside the jacket.
The 75°C Column: Feeders and Larger Equipment
You can use the 75°C column for circuits rated over 100 amps, or for wire sizes larger than 1 AWG, provided the equipment terminations (like a main breaker panel lug or a large HVAC disconnect) are explicitly marked as 75°C rated. Most modern commercial panels and heavy-duty contactors carry this rating. You will also use this column when pulling THHN/THWN-2 in conduit for a 30A or 50A subpanel feeder, assuming the lugs at both ends are 75°C rated.
The 90°C Column: Strictly for Derating
The 90°C column is almost never used to determine the final allowable ampacity of a circuit. Its primary purpose is to serve as the baseline for derating calculations. You start with the 90°C ampacity, apply your correction factors, and then verify that the final derated number does not exceed the 60°C or 75°C ampacity limits for the termination hardware.
How Derating Modifies Your Base Ampacity
A wire gauge chart assumes ideal conditions: an ambient temperature of 30°C (86°F) and no more than three current-carrying conductors bundled together. When real-world conditions deviate from this baseline, the wire's ability to dissipate heat drops, and you must reduce (derate) its allowable ampacity.
Ambient Temperature Correction
If you are routing wire through a hot attic in the middle of summer, the ambient temperature might reach 50°C (122°F). According to NEC Table 310.15(B)(1), you must multiply the base ampacity by a correction factor. For a 50°C ambient environment, the multiplier for 90°C insulation is 0.82.
Example: You are running 8 AWG THHN to a detached garage through an attic. The 90°C base ampacity is 55A. Multiplying 55A by 0.82 gives you 45.1A. You must then check the termination limits: since 8 AWG is typically terminated on 75°C lugs (max 50A), your final allowable ampacity is capped at 45.1A. You would protect this with a 40A breaker.
Conductor Bundling (More Than 3 Current-Carrying Wires)
When you pull more than three current-carrying conductors in a single conduit, the wires heat each other up. NEC Table 310.15(C)(1) requires you to apply a percentage adjustment.
- 4 to 6 conductors: Derate to 80%
- 7 to 9 conductors: Derate to 70%
- 10 to 20 conductors: Derate to 50%
Example: You are pulling two 240V circuits (4 hot wires total, plus a ground) in one EMT conduit using 10 AWG THHN. The 90°C base ampacity for 10 AWG is 40A. Because you have 4 current-carrying conductors, you multiply 40A by 0.80, resulting in 32A. Since 32A is greater than the 30A limit for 10 AWG terminations, you can safely use 30A breakers for both circuits. If you added a third circuit (6 hot wires), you would still use the 80% factor, but if you added a fourth (8 hot wires), you would drop to 70% (40A x 0.70 = 28A), forcing you to step up to 8 AWG wire to maintain 30A circuits.
What This Wire Gauge Chart Cannot Tell You
While this NEC wire gauge chart pdf replacement gives you the thermal limits of the wire, it does not account for the physics of long-distance power transmission or the mechanical realities of your hardware. Before finalizing your materials list, verify these three missing variables.
1. Voltage Drop Over Distance
Ampacity tells you the wire won't melt; it doesn't tell you if your equipment will actually run. If you are running a 120V circuit 150 feet to a shed on 12 AWG wire, the wire is perfectly safe at 20A, but the voltage at the receptacle might drop below 110V under load. This can cause motors to overheat and electronics to brown out. As a rule of thumb, keep voltage drop under 3% for branch circuits and 5% total from the service entrance. For long runs, you must use a voltage drop calculator and often upsize your wire by one or two gauges, regardless of what the ampacity chart says.
2. Physical Lug Capacity
The chart might tell you that 4 AWG copper is required for a specific 70A feeder run after derating. However, if you look at the physical breaker or disconnect switch you bought, the mechanical lugs might only be rated to accept a maximum of 6 AWG wire. You cannot safely jam a 4 AWG wire into a lug designed for 6 AWG, nor should you trim strands off the wire to make it fit. If the math demands a larger wire than the hardware can accept, you must buy hardware with larger lugs or use a pigtail reduction (if legally permitted by the AHJ for that specific equipment).
3. Aluminum vs. Copper
This chart is exclusively for copper. If you are buying SER cable for a 200A service upgrade or a large subpanel feeder, you will likely be using aluminum (like 2-2-2-4 AL) because it is significantly cheaper. Aluminum has a higher resistance and lower ampacity per gauge. For example, 2 AWG copper is good for 115A (90°C), but 2 AWG aluminum is only good for 90A (75°C). Always verify the material stamp on the wire jacket (AL or CU) before applying these numbers.
