What is a branch circuit?

A branch circuit is defined as the section of an electrical system that extends from the final overcurrent protection device, such as a circuit breaker or fuse, to the outlets or devices that it powers. This definition is crucial because it emphasizes the role of the branch circuit in distributing electrical power within a facility or to specific loads. Essentially, it serves as the pathway through which electricity flows from the protective device to various electrical devices or loads, making it an integral part of the electrical distribution system.

While lighting circuits are a common application of branch circuits, they are not exclusive to lighting, which rules out the option suggesting that a branch circuit supplies only lighting. The term also does not refer to connections to the main utility supply, as that typically indicates the service entrance circuits rather than branch circuits. Lastly, while backup systems may use secondary circuits, the designation of a branch circuit does not apply specifically to those systems. Thus, this understanding of branch circuits is key for load calculations and planning within electrical systems.