What is the function of bonding in aircraft electrical systems?

• A. To ensure a common electrical potential and provide a low-impedance fault path
• B. To isolate circuits to prevent interference
• C. To store energy for backup power
• D. To limit current in the main bus

Answer: (A)

Bonding establishes and maintains a common electrical potential across all exposed metallic parts of the aircraft and provides a low-impedance path for fault currents to return to their source. This keeps parts at the same voltage, reduces the risk of shocks and arcing, helps control static buildup and EMI, and ensures protective devices respond quickly to faults by carrying the current safely back to the source. The other ideas don’t fit because bonding is not about isolating circuits, storing energy, or limiting current in the main bus; those functions come from isolation/shielding practices, energy storage devices, and protective devices, respectively.