Aluminum conductors are a cost-effective choice for service entrances and large feeders, but require a larger AWG size than equivalent copper. A commonly used rule of thumb is to go two AWG sizes larger in aluminum than copper for equivalent ampacity — for example, 2 AWG copper (95A) is roughly equivalent to 1/0 AWG aluminum (100A) at 75°C per NEC Table 310.16. Aluminum wiring also requires anti-oxidant compound at connections, use of aluminum-rated connectors and terminals, and specific torque values. This calculator shows side-by-side copper and aluminum sizing for any ampacity so you can compare cost versus weight versus conduit fill.
200A service entrance: Copper — 3/0 AWG (200A at 75°C). Aluminum — 350 kcmil (200A at 75°C). Aluminum is approximately 60% cheaper by weight for equivalent ampacity on large feeders.
This is a variant of the full Wire Size Calculator — which supports all wire materials, derating factors, and load types in a single tool.
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