2 AWG Ampacity Chart: Copper vs Aluminum Wire Sizing Guide

If you are pulling 2 AWG wire, you are likely feeding a 100-amp subpanel, wiring a heavy-duty EV charger, or running service entrance conductors. The direct answer for 2 AWG ampacity under standard NEC rules (Table 310.16) is 115 amps for copper and 90 amps for aluminum when using the 75°C column. However, picking the right number from the chart depends entirely on your termination ratings, conduit fill, and whether this is a residential service or a standard feeder.

Below is the complete reference data you need to size your breakers, lugs, and conduit correctly, without failing inspection or melting a terminal.

The 2 AWG Ampacity Reference Chart (NEC Table 310.16)

How to read this table: This data is sourced directly from NFPA 70 (NEC) Table 310.16. The values assume an ambient temperature of 30°C (86°F) and no more than three current-carrying conductors in a single raceway or cable. The columns represent the temperature rating of the wire insulation (THHN/THWN-2 or XHHW-2). We have included 3 AWG and 1/0 AWG to provide context if your load calculation forces you to upsize or downsize.

Which Temperature Column Actually Applies to Your Install?

The most common mistake DIYers and junior apprentices make is looking at the 90°C column because THHN wire is rated for 90°C, and assuming they can run 130 amps through 2 AWG copper. You almost never can.

Under NEC 110.14(C), the ampacity of your wire is limited by the lowest temperature rating of any connected component. In residential and light commercial panels, the breakers, bus bars, and terminal lugs are overwhelmingly rated for 75°C. Therefore, you must use the 75°C column to determine your maximum breaker size. For 2 AWG copper, that caps your overcurrent protection at 115A (which means you use a 110A breaker, as 115A is not a standard standard breaker size under NEC 240.6). For 2 AWG aluminum, you are capped at 90A.

The Residential 83% Exception (NEC 310.12)

There is one massive exception to the 75°C rule that causes endless confusion on forums. If your 2 AWG aluminum wire is being used specifically as service entrance conductors for a 100-amp residential dwelling service, NEC 310.12(A) allows you to apply an 83% multiplier. Because 100A x 83% = 83A, and 2 AWG aluminum is rated for 90A at 75°C, it is perfectly legal for a 100A main service drop. This 83% rule does not apply to subpanel feeders, detached garages, or commercial buildings.

Derating 2 AWG Wire: When the Chart Value Drops

The ampacity table above assumes ideal conditions: 30°C (86°F) ambient air and no more than three current-carrying conductors in the conduit. When real-world jobsite conditions change, you must use the 90°C column as your starting baseline, apply derating multipliers, and then compare the result to the 75°C column limit. You must use the lower of the two final numbers.

Scenario 1: Bundling More Than 3 Conductors

If you are pulling two hots, a neutral, and a ground for a multi-wire branch circuit or a feeder with a neutral, you have three current-carrying conductors (the ground does not count). But if you pull two separate 240V circuits in the same conduit (four hots), you have four current-carrying conductors. NEC Table 310.15(C)(1) requires an 80% adjustment factor.

• Baseline (90°C Cu): 130A
• Derated (x 0.80): 104A
• Final Limit: 104A is lower than the 75°C limit of 115A, so your wire is now legally capped at 104A. You cannot use a 110A breaker; you must drop to a 100A breaker.

Scenario 2: High Ambient Temperatures

If your conduit runs across an unventilated attic in the summer or along a hot roof deck, the ambient temperature easily exceeds 30°C. If the attic reaches 45°C (113°F), NEC Table 310.15(B)(1) dictates an 87% correction factor for 90°C insulation.

• Baseline (90°C Al): 100A
• Derated (x 0.87): 87A
• Final Limit: Your 2 AWG aluminum is now only good for 87A. If you need 90A, you must upsize to 1 AWG aluminum or reroute the conduit out of the hot zone.

What the Ampacity Table Cannot Tell You

Ampacity charts only tell you how much current the wire can handle before the insulation melts. They do not account for physics over distance or physical installation constraints. Before you buy a 500-foot spool of 2 AWG, check these three limitations.

1. Voltage Drop Over Distance

The NEC recommends keeping voltage drop under 3% for branch circuits and feeders (5% total). If you push 100 amps through 2 AWG copper on a 240V circuit, you will experience roughly a 3.8-volt drop per 100 feet.

• At 50 feet: ~1.9V drop (0.8%) - Perfectly fine.
• At 100 feet: ~3.8V drop (1.6%) - Acceptable.
• At 200 feet: ~7.6V drop (3.2%) - Exceeds the 3% recommendation. Your EV charger may throw fault codes, or your subpanel lights will dim when the compressor kicks on.

For runs over 150 feet at 100A, use a dedicated voltage drop calculator and expect to upsize to 1/0 AWG or 2/0 AWG copper to maintain power quality.

2. Conduit Fill and Physical Pulling

2 AWG wire is thick and stiff. Under NEC Chapter 9, Table 1, conduit fill is limited to 40% for three or more conductors. If you are pulling three 2 AWG THHN conductors and one 8 AWG ground, you need a minimum of 1-inch PVC Schedule 80 or 1.25-inch EMT. Trying to jam 2 AWG into 3/4-inch conduit will result in damaged insulation, jammed pulls, and a failed inspection. Always use wire pulling compound (lubricant) rated for THHN/XHHW when pulling this gauge.

3. Torque Specifications

A wire sized perfectly on paper will still burn up if the termination is loose. NEC 110.14(D) mandates that you tighten lugs to the manufacturer's specified torque. For 2 AWG wire in standard 100A panelboard lugs, this typically requires between 40 in-lbs and 50 in-lbs of torque. You cannot guess this with a standard screwdriver. You must use a calibrated torque screwdriver or a digital torque adapter. An under-torqued 2 AWG lug will arc, generate immense heat, and eventually cause a panel fire, regardless of how perfectly you calculated the derating.