Which of the following is NOT a primary component of the aircraft electrical system?

The aircraft electrical system is primarily designed to generate, distribute, and manage electrical power throughout the aircraft, which includes various components specifically related to electrical functions.

Wiring is crucial as it connects all electrical components and facilitates the flow of electrical current. Switches are essential for controlling the electrical circuits by allowing or interrupting the flow of electricity. Circuit breakers serve as protective devices within the system, preventing overloads and short circuits by interrupting the flow of current in case of faults.

On the other hand, fuel tanks do not play a role in the electrical system. Their purpose is to store fuel for the aircraft's engines, making them a component of the fuel system rather than the electrical system. This distinction is key to identifying the components that are directly involved in the aircraft’s electrical functions.