The service entrance is the next design step (after the considerations in Chapter 1) in the design of a safe, reliable and flexible electrical power distribution system. The designer generally knows how much power the site will require and any unusual needs. While details about individual loads still may not have been decided, the decision whether the operations will be around-the-clock or just on the day shift will probably have been made by this time. In addition, any processes with unusual power requirements, especially large peak loads, will generally be known.
The service entrance is usually the boundary between the customer's facility and the electric utility supplying power. It consists of the conductors and all necessary power control and safety equipment, and is normally located near the point of entrance of the supply conductors to a building (or at a customer-owned substation). This equipment usually consists of one or more circuit breakers or fusible switches.
For help in designing a safe, adequate service entrance installation, refer to the NEC and other sources as appropriate.
