Side-by-side guides covering conductor materials, wire gauges, construction types, and insulation ratings. Each comparison includes NEC ampacity data and practical guidance on when to use which.
Compare conductivity, weight, cost, ampacity, and when to use each material.
Wire construction compared: flexibility, resistance, applications, and when to use each type.
Compare ampacity, NEC overcurrent rules, voltage drop, and when to use each gauge for residential circuits.
Insulation types compared: PVC/nylon vs XLPE, temperature ratings, wet location use, and NEC requirements.
| Property | Copper | Aluminum (EC-1350) |
|---|---|---|
| Conductivity | 100% IACS | 61% IACS |
| Resistivity at 20°C | 1.72 × 10⁻⁸ Ω·m | 2.83 × 10⁻⁸ Ω·m |
| Density | 8,960 kg/m³ | 2,700 kg/m³ |
| Size for 100A (75°C) | 3 AWG | 1 AWG |
| Size for 200A (75°C) | 3/0 AWG | 250 kcmil |
Sizes from NEC Table 310.16 with 75°C terminations. Stranded conductors are required in raceways from 8 AWG up (NEC 310.3(C)); below that, solid 14–10 AWG is standard in NM-B cable.
For 15–30A branch circuits, use copper: small aluminum branch wiring has a poor track record at connections, and copper devices are cheaper and easier to find. For feeders and services of 60A and up, aluminum (AA-8000 or 1350 alloy) with AL/CU-rated lugs saves a large share of the cost and weight. Choose stranded conductors for anything pulled through conduit at 8 AWG and larger, for cords, and for anything that moves; solid wire is fine for 14–10 AWG cable in walls.