An arc flash is an electrical event and a blast event. The worker may suffer deep burns, hearing loss, eye injury, trauma from pressure or a fall, and inhalation injury without directly touching a conductor. The investigation should preserve the electrical system in its incident state and explain why the worker was exposed when the fault occurred.
Identify the exact equipment and work
Record the switchgear, panel, disconnect, transformer, busway or other equipment involved, along with manufacturer, model, serial number, voltage and location. Photograph the enclosure, labels, doors, covers, tools, test instruments and damaged components before repair or cleaning.
Define the task precisely. Switching, testing for absence of voltage, racking a breaker, troubleshooting and installing components present different questions. Preserve the work order, switching order, permit, job briefing, drawings and communications describing what the worker was expected to do.
Preserve the system state and event data
Secure relay, breaker and trip-unit records, fault codes, sequence-of-events files, meter data, supervisory-control logs and building video. Record device settings and time synchronization before anyone resets or replaces equipment. Preserve upstream and downstream protective devices that may have affected fault duration.
Obtain the current one-line diagram, earlier versions and modification records. Compare the drawing with the system as built. New transformers, changed conductors, altered breaker settings or added generation can affect available fault current and clearing time even when an old label remains on the enclosure.
Examine the decision to work energized
For covered general-industry work, 29 C.F.R. section 1910.333 generally requires live parts to which an employee may be exposed to be deenergized before work on or near them unless the employer can demonstrate that deenergizing creates additional or increased hazards or is infeasible because of equipment design or operational limitations.
Preserve the written explanation for energized work, any permit, shutdown request, operational constraints and approval chain. A statement that the process was continuous does not itself resolve whether deenergizing was infeasible. The actual system, work and alternatives should be examined.
Test whether the equipment was truly deenergized
Document the disconnecting means, locks, tags, verification test, test-instrument check and any stored or induced energy. OSHA’s electrical materials explain that conductors and equipment treated as deenergized must meet the applicable lockout and tagging steps. Equipment that was turned off but not placed in the required condition may still have been treated as energized work.
Trace every possible feed, including control power, backfeed, generators, solar systems, capacitors and connected equipment. Preserve voltage-test data and identify who established and verified the electrically safe condition.
Reconstruct the fault and protective-device response
Qualified electrical analysis may need to examine the initiating fault, phase involvement, conductor damage, loose connections, contamination, insulation failure, foreign objects, tool marks and equipment condition. Determine which protective device opened, its setting, actual clearing time and whether another device should have operated first.
Maintenance and testing records can matter when a breaker, relay or fuse does not respond as expected. Obtain coordination studies, short-circuit studies, arc-flash analyses, acceptance testing and later changes. Do not energize or destructively test the equipment until the interested parties have a fair inspection opportunity.
Review boundaries, labels and protective equipment
Preserve the arc-flash label in place and obtain the study or table used to create it. Record the available incident-energy information, working distance, boundary, equipment condition and task assumptions. A label may no longer describe the system if settings, sources or configuration changed.
Collect the worker’s clothing, face shield, hood, gloves, hearing protection, tools and inspection records. Protective equipment may reduce harm, but it does not answer whether energized exposure should have existed or whether the study and label were current. Damage patterns and medical findings may also help reconstruct the worker’s position.
Map responsibility for the system and work
Identify the facility owner, direct employer, electrical contractor, engineering firm, equipment manufacturer, testing company and any utility or generator operator involved. Determine who controlled shutdown approval, system drawings, protective-device settings, maintenance, labeling, worker qualification and the task itself.
A Louisiana industrial-accident review can separate the employment claim from possible responsibility of another contractor, equipment company or premises operator. Our guides explain when a work injury may support a third-party lawsuit and how outside-company control can matter beyond workers’ compensation.
Editorial & Legal Accuracy Notice (Louisiana)
Sources checked: September 24, 2026
Electrical origin, regulatory coverage, energized-work justification, incident energy, protective-device operation, injury mechanism and civil responsibility require project-specific technical and legal analysis.