Case studies
Arc Flash & Power System Study Case Studies
Real engineering results from real facilities — how standard updates and modeling choices change the numbers behind your PPE requirements, labels, and equipment ratings.
Arc flash · IEEE 1584
A hospital switchboard: 34.56 cal/cm² under the old standard, 23.56 under the new one
We modeled a county hospital's 480Y/277V system — served by a 500 kVA utility transformer and a main switchboard feeding three automatic transfer switches for the Life Safety, Critical, and Equipment branches — under both IEEE 1584-2002 and IEEE 1584-2018. The 2018 standard's added electrode configurations and actual equipment enclosure dimensions raised incident energy at most buses, with the largest jump at bus ECLDP (7.38 → 15.73 cal/cm²), but lowered it at others, including a 10.99 cal/cm² drop at the main switchboard itself. The takeaway: a facility's arc-rated PPE requirements and labels can change on the standard alone, with no equipment changes at all.
Short circuit · VFD modeling
700+ buses, 88 VFDs, one panel where bypass mode changed the answer
On a system with more than 700 buses and 88 variable-frequency-drive motors totaling 2,988 HP, all with bypass capability, we modeled short circuit currents in SKM with the VFDs in bypass mode versus normal operating mode. Only one panel saw its calculated short circuit current exceed its rating when VFD bypass was engaged — a condition that never appeared with the drives in normal mode. Most differences across the system were modest, but the variability was large enough that we recommend checking VFD bypass state at each high-impact location rather than assuming it's negligible.
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