Copper Cable Sizing [portable] Official

| AWG/kcmil | Ampacity (75°C) | Typical Use | Max distance for 15A @ 120V (<3% drop) | | :--- | :--- | :--- | :--- | | 14 | 20A | Lighting, general outlets | 30 ft | | 12 | 25A | Kitchen outlets, 20A circuits | 40 ft | | 10 | 35A | Water heaters, AC units | 65 ft | | 8 | 50A | Small subpanels, ranges | 80 ft | | 6 | 65A | EV chargers, large ovens | 100 ft | | 4 | 85A | Subpanels, feeders | 130 ft | | 2 | 115A | Main feeders, heat pumps | N/A (requires calc) |

Note: Always verify with local codes and actual installation conditions. copper cable sizing

In the modern world, electricity flows like blood through a circulatory system. But unlike veins and arteries, which are fixed in size, the copper cables in our buildings, factories, and renewable energy systems are designed by human choice. And that choice—choosing the right thickness of copper—is far more nuanced than "the thicker, the better." | AWG/kcmil | Ampacity (75°C) | Typical Use

The best electricians don't just read ampacity tables; they understand why the table says what it does. They account for the heat, the distance, and the neighbors in the conduit. For AC power (50/60 Hz), skin effect is

False. For AC power (50/60 Hz), skin effect is negligible at typical sizes (< 250 kcmil). A 10 AWG solid and 10 AWG stranded have the same ampacity. Stranded is just easier to bend.