The Basics of Conductor Sizing - Part 1: How do you select a conductor that won't melt?

摘要

Unfortunately, making the proper choices when sizing electrical conductors can get complicated. For one thing, the ampacity tables can be very confusing - especially if you don't understand the "why" behind them and the correction factors you will most likely apply when using them. A key factor is impedance, which is the opposition to current flow. In DC circuits, we call it "resistance." Whenever current (I) flows through a conductor, the opposition (R) to current flow produces heat. We call this current resistance heating "IR heating."