AWG Cable Amps Chart: Wire Size to Ampacity Reference (NEC 310.16)

The most common residential AWG cable amps (ampacities) for copper conductors in a standard 30°C (86°F) environment are: 14 AWG (15A), 12 AWG (20A), 10 AWG (30A), 8 AWG (40A), 6 AWG (55A), and 4 AWG (70A). These baseline values assume the wire is installed in a raceway or cable assembly with no more than three current-carrying conductors. If you are sizing wire for a branch circuit or feeder, you must cross-reference these base numbers with termination temperature limits and environmental derating factors before selecting your breaker.

The Master AWG Cable Amps Chart (NEC Table 310.16)

How to read this table: The data below is sourced directly from NEC Table 310.16 (formerly 310.15(B)(16)), the definitive standard published by the National Fire Protection Association (NFPA). The table is split by conductor material (Copper vs. Aluminum/Copper-Clad) and insulation temperature rating (60°C, 75°C, and 90°C). The values represent the maximum continuous current the wire can carry without exceeding its insulation's thermal limits, assuming an ambient air temperature of 30°C (86°F) and no more than three current-carrying conductors bundled together.

Bookmark Quick-Jumps: For standard residential branch circuits, you will almost exclusively use the Copper 60°C column for 14, 12, and 10 AWG due to termination limits. For larger feeders (8 AWG and up), the Copper 75°C or Aluminum 75°C columns are the standard baseline.

Which Temperature Column Applies to Your Installation?

The most common mistake DIYers make is looking at a spool of 12 AWG THHN wire, seeing it rated for 90°C, and assuming they can use the 30A column. You cannot. NEC Section 110.14(C) dictates that the ampacity of a circuit is limited by the lowest temperature rating of any connected termination, device, or conductor in the circuit.

• The 60°C Column: Mandatory for circuits rated 100A or less using 14, 12, or 10 AWG wire. Standard residential receptacles (15A and 20A) and basic toggle switches are typically only rated for 60°C terminations. Therefore, a 12 AWG wire on a 20A receptacle circuit is legally capped at 20A, regardless of the wire's 90°C insulation.
• The 75°C Column: The standard for most modern residential breakers, panelboard lugs, and larger equipment (like ranges, dryers, and subpanel feeders). If you are pulling 6 AWG THHN to a 60A breaker and a 75°C-rated terminal block, you use the 65A value.
• The 90°C Column: Almost never used for final ampacity sizing in residential work. Its primary legal use is as the starting point for calculating derating adjustments (explained below) before applying the termination temperature cap.

Derating Factors: When Base Ampacity Drops

The chart above assumes ideal conditions. In the real world, wires generate heat, and if they cannot dissipate it, the insulation melts. You must apply derating multipliers to the 90°C column (for copper) in two specific scenarios:

1. Ambient Temperature Correction: If your conduit runs through a hot attic (e.g., 50°C / 122°F), the wire's capacity drops. You multiply the 90°C base ampacity by the correction factor in NEC Table 310.15(B)(1). For 50°C ambient, the factor is 0.82.
2. Bundling (More than 3 Current-Carrying Conductors): If you pull four or more current-carrying wires through the same raceway (like a multi-wire branch circuit or a 3-phase feeder), they heat each other up. NEC Table 310.15(C)(1) requires you to multiply the 90°C ampacity by 80% for 4-6 conductors, 70% for 7-9 conductors, and so on.

Worked Example: You are pulling four 12 AWG THHN copper wires (two circuits sharing a neutral, but let's assume 4 current-carrying for a 3-phase or strict multi-wire scenario) through a conduit in a standard 30°C attic.
• Base 90°C ampacity for 12 AWG = 30A.
• Bundling derate for 4 wires = 80%.
• 30A × 0.80 = 24A adjusted ampacity.
However, because you are terminating on standard 15A/20A receptacles (60°C limit), you must still protect this wire with a 20A breaker maximum. The 90°C column saves you here, proving the wire can handle the heat of the bundle, but the termination rule caps your final breaker size.

What This Table Cannot Tell You (Edge Cases & Limits)

Ampacity charts only solve for thermal limits under continuous load. They do not account for the following critical engineering realities:

• Voltage Drop: NEC Table 310.16 will tell you that 14 AWG can safely carry 15A. But if you run 14 AWG for 150 feet to a 15A space heater, the voltage drop will be roughly 9.4% (nearly 12V lost). The NEC recommends keeping branch circuit voltage drop under 3%. For long runs, you must upsize the wire purely for voltage drop, even if the breaker size remains the same.
• Short-Circuit Withstand: If a massive fault occurs, the wire must survive the milliseconds before the breaker trips. Standard ampacity tables don't calculate fault-current thermal stress.
• Physical Lug Fit: You might calculate that 2 AWG aluminum is perfect for a 90A feeder, but the physical lugs on your specific disconnect switch might only accept up to 4 AWG. Always check the manufacturer's spec sheet for termination wire ranges.

AWG Cable Amps FAQ

How many amps can 6 AWG wire handle?

For copper wire, 6 AWG is rated for 55A in the 60°C column, 65A in the 75°C column, and 75A in the 90°C column. In standard residential practice, 6 AWG copper THHN/THWN is typically protected by a 60A breaker when terminating on standard 75°C panel lugs and equipment, making 65A the functional thermal limit, capped at 60A for overcurrent protection.

Can I use aluminum wire for a 50-amp circuit?

Yes, but you must upsize. Aluminum has higher resistance than copper. For a 50-amp circuit, you need 6 AWG copper or 4 AWG aluminum (using the 75°C column, which yields 65A for aluminum, safely covering the 50A load). Never use aluminum for standard 15A or 20A receptacle branch circuits, as the small strand sizes are prone to oxidation and creep at screw terminals not specifically rated for aluminum (CO/ALR).

Does AWG cable ampacity change for DC versus AC?

No. The ampacity (thermal current limit) of a wire is identical for AC and DC because heat generation (I²R losses) is based on RMS current, which is equivalent to DC current. However, voltage drop is vastly more critical in low-voltage DC systems (like 12V or 24V solar/battery setups). A 2V drop on a 120V AC line is negligible (1.6%), but a 2V drop on a 12V DC system is catastrophic (16.6%), meaning DC wiring often requires massively oversized conductors compared to AC equivalents.

What size wire do I need for a 100-amp subpanel feeder?

Assuming standard 75°C terminations at both the main panel and the subpanel, you need 4 AWG copper (rated 85A, wait—4 AWG is 85A, so for a strict 100A feeder you actually need 3 AWG copper at 100A, or more commonly 2 AWG aluminum at 90A, wait, 2 AWG Al is 90A. Let's correct this: For a full 100A feeder, you need 3 AWG Copper or 1 AWG Aluminum based strictly on the 75°C column. However, NEC 220.87 and standard load calculations often show a 100A subpanel rarely draws a continuous 100A, allowing the use of 4 AWG Copper or 2 AWG Aluminum if the calculated load permits. Always verify the exact calculated load before sizing feeders.)