A manufacturing company was building a small data center fed by several 3000kVA, 4160/480V, dry-type, delta/wye transformers. Upon energization of one transformer from an alternate feed, a fault occurred, which caused its upstream medium voltage (MV) breaker to trip. The transformer was then re-energized from the primary feed, and facilities management personnel observed a flash. Assuming the breaker was the issue, the team inspected and tested the breaker. Finding no obvious problems with the breaker,…
