ARC‐RESISTANT EQUIPMENT

The arc‐resistant switchgear has been more popular in Europe than in North America. In North America, the impetus has been to lower the arc flash hazard by system innovation and protection systems rather than reinforcing the equipment to withstand the internal arcing faults. This chapter presents IEEE and IEC accessibility types for arc‐resistant equipment. It discusses two methodologies for obtaining arc‐resistant ratings: duration ratings and device‐limited ratings. If the switchgear is of metal‐enclosed design or nonsegregated construction, an arc flash occurrence can propagate within the enclosure, and the only protection is pressure relief vents. The chapter briefly describes the assessment of test results of equipment according to IEEE guide. When the protective device is located some distance away and the equipment is cable connected, the effect of cable impedance should be considered. It will reduce the bolted three‐phase fault current at the equipment.