What is the maximum number of services a building or structure shall be supplied by, unless specifically permitted otherwise?

The correct answer is that a building or structure shall be supplied by a maximum of one service, unless specifically permitted otherwise. This rule is set forth in the National Electrical Code (NEC) to ensure safety and reliability in electrical service distribution.

Having a single service simplifies the design and operation of the electrical system, reduces potential points of failure, and helps maintain a clear delineation of responsibility for the supply and distribution of electrical power within the building. It also helps in facilitating maintenance and troubleshooting, as there is only one source of power to manage, making it easier for electricians to pinpoint issues and perform necessary repairs without the complexity of multiple services.

Exceptions to this rule can be found in the NEC, where multiple services may be permissible under specific circumstances, such as for large commercial or industrial installations where separate services may be required for different uses or to comply with other regulations. However, the default is to limit a building or structure to one service to streamline power distribution and enhance safety.