What is the minimum conductor size for a 100 amp service?

For a 100 amp service, the minimum conductor size is determined by the National Electrical Code (NEC) guidelines, which specify that for copper conductors, the minimum size required is 4 AWG. This size is sufficient to handle the current load without overheating and is also suitable for most residential applications, taking into account factors like ambient temperature and the number of conductors in a raceway.

Copper conductors have a higher conductivity compared to aluminum, which means they can carry more current in a smaller size. Therefore, while 6 AWG copper is sometimes used for smaller loads, it does not meet the requirements for a 100 amp service under typical conditions, as it would not provide the necessary safety margin.

Understanding these guidelines ensures that the installation adheres to safety standards and prevents potential electrical hazards, making 4 AWG copper the correct choice for minimum conductor size in this scenario.