What is a primary function of electrical boxes in branch-circuit wiring?

The primary function of electrical boxes in branch-circuit wiring is to serve as conductor splice points. This means that they provide a secure and organized space for connecting and joining electrical wires. By allowing splices to be neatly contained and accessible, electrical boxes facilitate easier maintenance and modifications to the wiring in a safe manner. They help ensure that any connections are protected from damage and reduce the risk of electrical fires by minimizing exposure to environmental factors.

While some other functions may be associated with electrical boxes, such as the potential for housing circuit breakers or providing moisture protection in specific environments, these are not their primary roles in standard branch-circuit wiring configurations. The primary focus is on providing splicing locations for conductors to safely connect and distribute electrical power throughout a system.