Improvement in passive arc flash protection through limiting arcing duration

In the area of passive arc flash protection, as applied in low-voltage electrical equipment and tested to ANSI/IEEE C37.20.7-2007, IEEE Guide for Testing Metal-Enclosed Switchgear Rated Up to 38 kV for Internal Arcing Faults [1], a commonly used approach could be called "contain and direct". Arcing energy is contained by creating a reinforced, burn-through and leak-resistant shell used in combination with a pressure evacuation system. Limited attempts are made to reduce the duration of the arcing event. This approach, while successful, has the disadvantage of creating substantial damage to the equipment in question and potentially creating a significant quantity of toxic exhausted material. An alternate approach would be to reliably limit the fault duration and hence directly reduce damage and exhaust. What is proposed is that with a new design approach, a reliable shortening of the fault duration as well as reduction in short circuit current level can be obtained. This approach also has an additional benefit in that the likelihood of an arcing fault occurring is reduced as is the incident energy.