Which of the following is classified as a fitting?

A fitting is a component that is used to connect or join pieces of electrical equipment or conductors. In this context, a connector is specifically designed for this purpose, making it the correct choice. Connectors serve to establish electrical continuity and ensure safe connections between wires, devices, and circuits.

Receptacles and switches, while important electrical components, serve different functions. A receptacle provides an outlet for plugging in electrical devices, and a switch controls the flow of electricity to a circuit or device. Both of these components do not fall under the category of fittings, as they are intended for user interaction rather than the connection of conductors.

A breaker, or circuit breaker, is a protective device that interrupts the electrical circuit under fault conditions. Its primary role is to protect the circuit from overloads and short circuits, and like switches and receptacles, it does not serve the specific function of connecting pieces together.

Therefore, in the context of electrical fittings, the connector stands out as the component specialized for joining conductors, making it the correct classification.