Residential wiring follows a predictable pattern of common wire sizes matched to specific circuit types. General lighting and outlet circuits use 14 AWG (15A) or 12 AWG (20A). Small appliance circuits in kitchens require 12 AWG 20A circuits. Electric dryers need 10 AWG (30A). Electric ranges require 8 AWG (40A) or 6 AWG (50A). Air conditioners and heat pumps are sized by the nameplate MCA and MOP ratings. This calculator lets you enter the specific load for any residential circuit and receive the correct NEC 310.16 wire size with all required derating. Common residential circuits are pre-filled for fast lookup.
Electric dryer circuit: 30A at 240V. NEC 310.16 75°C column: 10 AWG copper = 35A. Use 10 AWG copper with 30A double-pole breaker. Wire a 4-wire circuit per NEC 250.140 Exception.
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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