“But the cost,” Lena protested weakly.
“Kid, that number on the spec sheet—it’s a lie. Or rather, it’s a truth that lives in a perfect world. A laboratory. It assumes the cable is floating in mid-air at 30 degrees Celsius, with nothing else around. But look where we are.” cable size current carrying capacity
He knelt and sketched in the dust on the floor. “But the cost,” Lena protested weakly
“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.” A laboratory
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.