What size feeder wire for a 3 gang meter socket for 3 100 amp panels?

For a 3-gang meter socket servicing three 100 amp panels, you would typically use a feeder wire size of 3 AWG copper or 1 AWG aluminum, assuming you are using the National Electrical Code (NEC) guidelines. This sizing is based on the need to handle a combined load of up to 300 amps while considering the ampacity and potential voltage drop. Always verify local codes and consult with a qualified electrician to ensure compliance and safety.