Wire Derating

Running wires through conduits, insulation, or underground traps heat. 📏 Key Derating Factors

Wires generate heat as electricity flows through them (due to resistance). The insulation around the wire is designed to withstand a certain maximum temperature (usually 60°C, 75°C, or 90°C). If the wire gets too hot, the insulation can degrade, crack, or melt, exposing the copper inside. wire derating

When multiple wires are packed into a single conduit or raceway, they trap each other’s heat. If the wire gets too hot, the insulation

is the practice of reducing a conductor's allowable ampacity—its maximum current-carrying capacity—to account for environmental factors that hinder heat dissipation. In electrical engineering, current flowing through a wire generates heat due to resistance; if this heat cannot escape, it can melt insulation, cause short circuits, or lead to fires. In electrical engineering, current flowing through a wire

Since 21.84 Amps is greater than 20 Amps, we can use this wire for a 20 Amp circuit. (If the calculation had resulted in 19 Amps, we would have had to downsize the breaker to 15 Amps or use larger wire).