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Incident energy describes the heat that touches a surface during an arc flash event. Reducing incident energy quickly and effectively is key for protecting people and equipment if an arc flash event happens.
Incident energy reduction not only reduces potential harm to personnel, but also catastrophic damage to the equipment. Using an energy-reducing active arc flash mitigation system such as arc quenching switchgear (AQS) is one of the seven incident energy reduction methods detailed in National Electric Code (NEC) Section 240.87, and it is highly effective.
The most common methods of arc energy reduction described in the NEC Section 240.87, when applied to low-voltage equipment, rely upon the clearing time of the upstream circuit breaker.
Power circuit breakers in particular have certain limits to their clearing time, which creates a minimum threshold for arc energy reduction. Achieving further reductions in arc energy requires alternate methods for capturing and containing the energy.
Current-limiting arc quenching devices represent the most significant advancement in arc flash safety in recent years. These devices provide superior personnel protection, advanced equipment protection and significant reductions in downtime in the event of an arc flash.
According to IEEE standard 1584, Section 9.7, incident energy is directly proportional to the duration of the arc fault. If the arc fault duration can be reduced, the incident energy is also reduced. Incident energy increases as available fault current and clearing time increases.
Because current-limiting arc quenching devices do not have moving parts with a great deal of mass, their operational time is much faster than that of a power circuit breaker.
Arc quenching switchgear is the most advanced and fastest clearing method to comply with NEC Section 240.87. Eaton’s Arc Quenching Switchgear detects and mitigates an arc flash in less than four milliseconds, creating a significant reduction in incident energy.
Learn more about the NEC Article 240.87 and the various technologies that can be used to meet the code and reduce arc energy and understand the advantages and disadvantages of any products and technologies that can be used to meet NEC Article 240.87.
Eaton’s innovation in arc mitigating technology reduces incident energy to a level exceeding traditional technology – significantly increasing safety and enabling the switchgear to withstand an arc flash event with minimal or no damage.
For example, by extinguishing an arc flash in less than four milliseconds, Eaton’s Arc Quencing Magnum PXR Switchgear dramatically reduces the incident energy available, while minimizing equipment damage and improving safety. Read our white paper for a detailed explaination of how Eaton’s Arc Quenching Switchgear quickly detects and extinguishes an arcing fault.
Reducing incident energy quickly and effectively is key for protecting people and equipment if an arc flash event happens. Read our blog to learn more about what makes arc quenching switchgear the most advanced and fastest clearing method to comply with NEC Section 240.87.
Unlike traditional arc-resistant switchgear, Eaton’s system is designed to minimize or completely eliminate damage to switchgear in the event of an arc flash. As a result, the switchgear can be quickly returned to service after an arc flash event to minimize downtime and repair costs.
Need help determining the best mitigation plan for your facility? Eaton can help.
