Safety Knights

If the equipment requires work/maintenance at any time, then, in MOST cases, an arc flash study has to be done regardless of who actually works on it. As the host facility, you're responsible for providing the contractor with the necessary equipment information they need to perform a proper risk assessment and select the proper PPE and boundaries.

In order for the person performing the work to perform a proper risk assessment, they either need (1) nominal voltage and incident energy levels (from the arc flash study), OR (2) nominal voltage and maximum available fault current, maximum fault clearing time, and need to know thier working distance from the exposed conductors. The caveat to the 2nd option listed is that if the worker is using the "table method" to select their PPE and the equipment is outside the listed parameters for available fault current, fault clearing time, or working distance, then the ONLY way to select your proper PPE is to do an arc flash study and determine the incident energy levels.

In short, an arc flash study is required >95% of the time. There are ways around it, but it requires you to maintain a LOT of documentation, ensure all of your overcurrent protection devices clear the fault within the maximum allowable time, the available fault current is below the maximum limits (generally under 25 kA), and you maintain the minimum working distance. There are lots of hoops to jump through to even TRY to avoid doing the arc flash study.