In an aircraft electrical system, what is a bus tie?

A bus tie is specifically designed to facilitate the interconnection of multiple electrical buses within an aircraft's electrical system, allowing them to operate together and share loads as needed. This connection is crucial for ensuring that there is an adequate supply of power throughout the aircraft, particularly in situations where one bus might be overloaded or compromised.

By tying buses together, electrical systems can enhance reliability and redundancy, allowing for more efficient power distribution and minimizing the risk of total electrical failure. Such a configuration allows for seamless transfer of electrical load between buses, which can be particularly important in maintaining power during critical phases of flight or when one source of power might be interrupted.

The other options describe concepts related to an aircraft's electrical system but do not accurately define a bus tie. For example, switching power between circuits relates to circuit breakers or switches rather than the specific function of tying buses together. Grounding systems address safety and protection aspects, while battery charging circuits pertain to maintaining the power supply rather than the interconnection of buses.