REFERENCE//NEC WIRE TABLES
WIRE SIZE REFERENCE TABLES
Complete reference tables for wire sizing, ampacity, resistance, and voltage drop calculations. Data sourced from NEC Chapter 9 tables and industry standards for accurate electrical design.
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Wire Ampacity Table
Based on NEC Table 310.16 - Allowable ampacities at 30°C ambient
NEC 310.16
| Size | CM | Copper | Aluminum | ||
|---|---|---|---|---|---|
| 75°C | 90°C | 75°C | 90°C | ||
| 14 | 4,110 | 15A | 15A | — | — |
| 12 | 6,530 | 20A | 20A | 15A | 15A |
| 10 | 10,380 | 30A | 30A | 25A | 25A |
| 8 | 16,510 | 40A | 45A | 35A | 40A |
| 6 | 26,240 | 55A | 60A | 45A | 50A |
| 4 | 41,740 | 70A | 80A | 60A | 65A |
| 3 | 52,620 | 85A | 95A | 70A | 75A |
| 2 | 66,360 | 95A | 105A | 80A | 90A |
| 1 | 83,690 | 110A | 125A | 95A | 100A |
| 1/0 | 105,600 | 125A | 145A | 110A | 120A |
| 2/0 | 133,100 | 145A | 165A | 125A | 135A |
| 3/0 | 167,800 | 165A | 195A | 145A | 155A |
| 4/0 | 211,600 | 195A | 230A | 170A | 180A |
| 250 | 250,000 | 215A | 255A | 190A | 205A |
| 300 | 300,000 | 240A | 285A | 210A | 230A |
| 350 | 350,000 | 260A | 310A | 230A | 250A |
| 400 | 400,000 | 280A | 335A | 250A | 270A |
| 500 | 500,000 | 320A | 380A | 280A | 310A |
| 600 | 600,000 | 350A | 420A | 310A | 340A |
| 750 | 750,000 | 385A | 475A | 350A | 385A |
| 1000 | 1,000,000 | 445A | 545A | 400A | 445A |
Note: Ampacities are for not more than 3 current-carrying conductors in raceway or cable. For 4-6 conductors, apply 80% derating. For 7-9 conductors, apply 70% derating.
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