Arc-Resistant Equipment

Because of the recent focus on arc flash hazards, arc-resistant equipment is becoming increasingly common in industrial facilities throughout North America. This article addresses arc-resistant equipment as it applies to low-voltage motor control centers (LVMCCs) [National Electric Manufacturing Association (NEMA) 600 V LVMCC/International Electrotechnical Commission (IEC) 690 V LV control gear}. A brief overview and history of applicable internal arc fault testing guides (IEEE C37.20.7 and IEC/TR 61641) are included. Test procedures and their considerations as well as arc-resistant assessment criteria are reviewed. An examination of various methods to achieve an arc resistant rating (device-limited rating and duration rating) as well as considerations for implementing arc-resistant equipment are addressed.