Two AWG still belongs to the seven-strand geometry in this Table 8 chart. The next larger label is where the chart switches strand count. That change is published geometry beside the resistance. It is not a temperature rating, and the calculator does not switch formulas when the strand count changes. It keeps using the stranded resistance cell.
The 60°C and 75°C copper cells are far enough apart here that the terminal choice moves the ampacity check by a meaningful amount. Read both before treating the label as one ampere rating. A 75°C terminal assumption has to be identified on the equipment. The general unmarked case for smaller equipment is not something you can upgrade by wishing.
The example current of 95 A equals the copper listing at 60°C. The prefilled calculator uses 240 V, 120 ft one way, 75°C insulation, and 75°C terminals. Those are inputs, not a required circuit.
The selected NEC 240.4(D) column in this tool has no special ceiling for 2 AWG. A blank is not permission to omit overcurrent protection. Table ampacity, the terminal cap, and voltage drop still apply.
Aluminum 2 AWG is listed at 75 A (60°C), 90 A (75°C), and 100 A (90°C), against copper 95 A, 115 A, and 130 A. Stranded resistance at 75°C is 0.319 Ω/kft aluminum and 0.194 Ω/kft copper. The same label is not the same conductor. Some equipment permits copper only.
This chart’s Table 8 row for 2 AWG publishes stranded resistance only (0.194 Ω/kft copper, 0.319 Ω/kft aluminum). The calculator uses that stranded value.
Table 8 lists 7 strands and 66360 circular mils for 2 AWG. The rounded nominal area is 33.62 mm². Bare stranded diameter is 0.292 in, which excludes insulation and is not conduit fill. The next guide size, 1 AWG, lists 19 strands.
| Listing | Copper | Aluminum |
|---|---|---|
| 60°C ampacity (A) | 95 | 75 |
| 75°C ampacity (A) | 115 | 90 |
| 90°C ampacity (A) | 130 | 100 |
| Stranded Ω/kft | 0.194 | 0.319 |
| Solid Ω/kft | — | — |
| Selected 240.4(D) ceiling (A) | — | — |
| Circular mils | 66360 | |
| Rounded mm² | 33.62 | |
| Strands | 7 | |
| Bare diameter (in) | 0.292 | |
For 2 AWG itself, not for whatever size the calculator recommends, Table 8 stranded copper resistance of 0.194 Ω/kft at 75°C gives 4.42 V (1.84% of 240 V) using 2 × I × R × L / 1,000. Reactance is omitted. Displayed volts are rounded to two decimals. The same inputs with stranded aluminum resistance 0.319 Ω/kft give 7.27 V (3.03%). If that percentage is outside the prefilled drop limit, the calculator will name a different size. That is the voltage-drop check, not a second ampacity table.
From 3 AWG to 2 AWG, the 75°C copper listing goes from 100 A to 115 A. Stranded copper resistance at 75°C goes from 0.245 Ω/kft to 0.194 Ω/kft.
From 2 AWG to 1 AWG, the 75°C copper listing goes from 115 A to 130 A. Stranded copper resistance at 75°C goes from 0.194 Ω/kft to 0.154 Ω/kft.
Planning estimate only. Consult local code and a qualified electrician before buying wire or energizing a circuit. Presets are hypothetical loads; this tool does not design motor, PV, battery, appliance, or EV installations.
Sources for these cells: existing Table 310.16 numerical cells in NFPA’s public development record, pp. 142–143 (proposed changes are not treated as adopted code) and NFPA 70 (2017), Chapter 9 Table 8, printed p. 689, in a third-party-hosted copy. The same publication supplies 110.14 (terminals and aluminum), 210.19/215.2 (continuous loads), 240.4(D) (small conductors), 250.24/250.32 (grounding), and 625.41/625.42 (EV loads). Schneider Electric’s voltage-drop formulas support the arithmetic; Table 8 AC results here omit reactance and assume unity power factor. Resistance and geometry are construction- and temperature-specific. Adopted editions and local amendments can differ.
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