Arc Flash is the result of a rapid release of energy due to an arcing fault between a phase bus bar and another phase bus bar, neutral or a ground. The fault typically starts with something creating the path of conduction or a failure such as a breakdown in insulation.


The cause of the short normally burns away during the initial flash and the arc fault is then sustained by the establishment of a highly-conductive plasma. The massive Arc Flash energy discharge burns the bus bars, vaporizing the copper and thus causing an explosive volumetric increase, the arc blast, conservatively estimated, as an expansion of 40,000 to 1.

The arc fault current is usually much less than the available bolted fault current and below the rating of circuit breakers. Unless these devices have been selected to handle the arc fault condition, they may not trip and the full force of an arc flash will occur. The challenge is to sense the arc fault current and shut off the supply in a timely manner before it develops into a serious arc flash condition.

Although OSHA doesn't directly state what to do about arc-flash hazards, OSHA 29 CFR 1910.132(d)(1) requires employers to evaluate the workplace for hazards. And based on these assessments, the employer must select and require the use of appropriate personal protective equipment (PPE) for its employees.

The NFPA70E in the US, and the Canadian CSA Z462 standard (will come into effect in 2008) deals with the Arc Flash Hazard assessment, management and safety procedures.
Among other issues these standards deal with arc hazard categorization, appropriate PPE selection, safe work procedure.

NFPA70E offers some information on calculation the incident energy level, but it doesn't go into much detail
IEEE Std. 1584 method is typically used for precise determination of incident energy levels.
There are several arc-flash software programs that are currently available on the market.

PowerCore Engineering currently uses EDSA Paladin Power System Analysis software package for system modelling and arc flash calculations.
  ->  see more info on  AC and DC Arc Flash


can offer you services in performing Arc Flash analysis including the following:


Additional Note

The Arc Flash Analysis merely a first step in implementing an Arc Flash Hazard Management Program. The results of the study shall be further utilized in steps such as: