Why do short-circuit studies calculate a bolted 3-phase fault condition?

Calculating a bolted 3-phase fault condition during short-circuit studies is crucial because it provides a comprehensive assessment of the maximum potential fault current that can occur in the electrical system. This type of fault represents the worst-case scenario, where all three phases are shorted together without any impedance. By considering this condition, engineers can determine the highest possible fault current that could flow through the system in the event of a fault, thereby ensuring that protective devices—such as circuit breakers and fuses—are adequately sized and rated to withstand these extreme conditions.

Furthermore, this analysis accounts for all potential fault current sources, including generators, transformers, and connecting conductors, ensuring that the system can be effectively designed and protected against the largest fault scenarios. This comprehensive understanding promotes electrical safety and reliability in the system, allowing for properly engineered solutions that can handle such occurrences without risking equipment damage or safety hazards.