A coupling in an electrical setup mainly serves to do what?

A coupling in an electrical setup is primarily designed to connect two wires together. This connection allows for the continuity of electrical current between different segments of wiring, enabling the flow of electricity to continue uninterrupted. By securely linking two wires, the coupling ensures that the connection is stable and can withstand the physical forces and electrical demands placed upon it.

The other choices do not accurately describe the primary function of a coupling. While switching power and measuring voltage are critical tasks in electrical systems, they are typically managed by different components such as switches and measuring instruments. Similarly, while insulation is important for safety and preventing electrical shorts, it is provided by insulating materials rather than the coupling itself. Thus, the correct answer effectively represents the main purpose of a coupling in an electrical setup.