Which switch ties together the generator and battery buses?

The bus tie switch is the component that connects the generator bus and the battery bus, allowing for the distribution of electrical power in the aircraft. When the bus tie switch is closed, it enables the electric systems to draw power from either the generator or the battery, depending on which is available and capable of providing the necessary power. This functionality is crucial for ensuring that electrical systems remain operational even if one source of power fails or is insufficient.

Moreover, the bus tie switch facilitates load sharing and can support the electrical system during various flight scenarios, enhancing redundancy and safety. The other switches mentioned do not serve this specific function; the power switch typically controls the main power supply, the circuit breaker switch deals with overload protection, and the battery switch primarily isolates the battery from the system when necessary.