Which conductor size is acceptable for 200 amp service?

For a 200 amp service, using 2 AWG aluminum conductors is indeed acceptable. This size is typically specified based on the National Electrical Code (NEC) guidelines, which provide the necessary ampacity ratings for various conductor materials and sizes.

Aluminum conductors have different ampacity characteristics compared to copper due to the material's conductivity. While aluminum is less conductive than copper, it is a common choice for large service feeds because it is lightweight and generally more cost-effective. Specifically, 2 AWG aluminum is rated to handle the current load for 200 amp service under most conditions.

In contrast, options like 6 AWG copper and 4 AWG aluminum are too small to safely carry 200 amps. While 1 AWG copper is suitable as it can handle the load, the option chosen correctly is 2 AWG aluminum, offering a balance between capacity, material type, and cost considerations.