In general, a building or structure shall be supplied by only ___ service(s).

In general, the National Electrical Code (NEC) stipulates that a building or structure should have only one service. This is to ensure a clear and manageable electrical supply system for the structure. Having a single service simplifies the design, installation, and maintenance of the electrical system, ensuring that the building's electrical load is adequately met without unnecessary complexity.

Furthermore, a single service means that there is a cohesive point of disconnect and protection for the entire building, which is critical in managing the electrical safety. This regulation helps in reducing potential hazards such as overloads or electrical malfunctions, as a unified service allows for easier monitoring and troubleshooting.

In some special situations, such as large commercial or industrial buildings, additional services might be allowed, but in general residential or typical commercial constructions, adhering to one service is the standard practice. This principle ensures overall safety and efficiency in electrical distribution within a building or structure.