What is the function of a bus tie in power distribution?

• A. It connects two or more bus bars so an operating generator can power multiple busses if one generator fails
• B. It isolates a failed bus from the system
• C. It regulates voltage on the main bus
• D. It feeds fuel to the engine when batteries fail

Answer: (A)

A bus tie is a cross-connection between two or more bus bars, allowing power to flow between them. This enables an operating generator on one bus to supply loads on the other buses and keeps essential systems powered if one generator or bus goes out of service. The tie helps with redundancy and load sharing, so system reliability improves because power can be transferred across busses rather than being lost when a single path fails. It’s not used to isolate a failed bus (that’s a switching/relaying function), it doesn’t regulate voltage directly (voltage regulation is done by regulators), and it doesn’t feed fuel to the engine.