For a 200 amp electrical service, the wire size depends on the conductor material and the installation conditions, but generally:

• Copper wire: Minimum size is 2/0 AWG, but 3/0 AWG copper wire is often recommended for safety margin and to handle voltage drop over longer distances. The ampacity of 3/0 copper wire is about 225 amps, which is suitable for a 200 amp service

• Aluminum or copper-clad aluminum wire: Minimum size is 4/0 AWG, with 250 kcmil aluminum wire also commonly used, especially for longer runs to reduce voltage drop. The ampacity of 4/0 aluminum wire is about 205 amps

Additional considerations:

• For long distances (e.g., 100 feet or more), upsizing the wire to reduce voltage drop is advisable. For example, at 200 feet, 3/0 copper or 300 kcmil aluminum wire may be needed to keep voltage drop within 3%

• Grounding conductors should be sized separately, typically 4 AWG copper or 2 AWG aluminum for a 200 amp service

• Always verify with the National Electrical Code (NEC) Table 310.12 and local codes, as ambient temperature, conduit fill, and installation conditions can affect the required wire size

In summary, the typical wire sizes for a 200 amp service are:

Conductor Material| Minimum Wire Size| Common Upsized Wire for Distance/Voltage Drop
---|---|---
Copper| 2/0 AWG| 3/0 AWG or 250 kcmil
Aluminum| 4/0 AWG| 250 kcmil or 300 kcmil

This ensures safe and efficient operation of a 200 amp electrical service.