What is the correct pipe size for a service entrance to a house?

The correct pipe size for a service entrance to a house typically depends on the electrical load and local building codes. For residential service, a common size is 1 inch for a 100-amp service and 1.25 inches for a 200-amp service. It's essential to consult the National Electrical Code (NEC) and local regulations to ensure compliance and proper sizing based on the specific requirements of the installation. Always consider factors like distance from the service panel and the type of conductors used.