When terminating feeders to the main switchgear, the feeders must be braced to withstand

• A. Magnetic forces due to fault currents
• B. Thermal expansion
• C. Vibration
• D. Physical impact

Answer: (A)

The main idea is that feeders terminated into main switchgear must be able to resist the strong electromagnetic forces that occur during fault currents. When a fault happens, fault currents rise dramatically, creating significant magnetic forces around the conductors and busbars. These forces can pull or push the feeders, potentially loosening terminations or causing damage if they aren’t restrained. Bracing provides the necessary mechanical stiffness to keep every connection secure during these high-current conditions. Thermal expansion, vibration, and physical impact are considerations in the overall design, but they don’t drive the primary need for bracing in the face of a short-circuit current.