What is the purpose of keeping a minimum distance from the phase bus to the closest steel member?

Keeping a minimum distance from the phase bus to the closest steel member is crucial to prevent arcing and potential short circuits. When electrical conductors operate under high voltage, there is the risk of electrical arcing occurring if they are placed too close to conductive materials, such as steel. This can lead to short circuits, which can cause significant damage to electrical systems, equipment failures, and safety hazards for personnel.

Maintaining this distance ensures that there is adequate spacing to prevent unintentional electrical discharges. Proper clearances are part of standard safety protocols in electrical installations, protecting both the equipment and anyone working in proximity to high-voltage systems. Therefore, the correct answer highlights an essential aspect of safety in electrical engineering.