Which of the following carries power from a main panel board to various subpanels?

The correct answer is feeders because feeders are specifically designed to carry electricity from the main panel board to various subpanels throughout a building or facility. They are a critical component in electrical distribution systems, ensuring that power is effectively transferred and distributed to different areas that require electricity.

Feeders typically consist of larger gauge wiring capable of handling the electrical load needed by the connected subpanels. This setup allows for the distribution of power to multiple circuits while maintaining efficiency and safety. Feeders can include bus bars or cables that link the main panel to subpanels, functioning as the primary route for electrical current.

Other choices do not serve the same function: transformers are used for voltage conversion rather than direct power distribution from one panel to another; conduits are protective pathways for electrical wires but do not carry power themselves; and circuit breakers serve as safety devices that interrupt electrical flow in the event of an overload or short circuit, not as carriers of power between sources.