Capacity |work| - Cable Size Current Carrying

Lena looked at her 85-amp load. “So my 100-amp rated cable… in this real world… what can it actually carry?”

He pointed up. The cable tray was a spaghetti bowl of a dozen other power cables, all running together for fifty meters in the hot, dusty ceiling. Above that, a steam pipe from the boiler room leaked a faint haze of heat. cable size current carrying capacity

“Hot enough to anneal the copper,” Marco grunted. “Now it’s soft as butter. Can’t carry a fraction of its rated load.” Lena looked at her 85-amp load

“Current-carrying capacity isn’t just about the copper,” Marco said. “It’s about getting rid of the heat the copper makes. Resistance creates heat. Every electron squeezing through that wire is like a runner in a tunnel. The more runners, the more heat. The insulation can only take so much before it gives up—usually 70, 90, or 105 degrees Celsius, depending on the type.” Above that, a steam pipe from the boiler

Lena took the book. From now on, she’d never look at a wire the same way again.

He handed her a worn copy of the electrical code, dog-eared at the ampacity tables.