Rachel M. Bugaris

Arc resistant equipment for low voltage motor control center applications

Due to recent focus on arc flash hazards, arc resistant equipment is becoming increasingly common in industrial facilities throughout North America. This paper addresses arc resistant equipment as it applies to low voltage motor control centers (NEMA 600V LVMCC/IEC 690V LV controlgear). 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 are reviewed, as well as arc resistant assessment criteria. An examination of the various methods to achieve an arc resistant rating (device limited rating and duration rating) are addressed as well as considerations for implementing arc resistant equipment in pulp, paper, and forest product applications.

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.

Improving Electrical Safety in the Workplace: Applying Prevention Through Design to Voltage Testing

Fundamental to an electrical safety program is establishing electrically safe work conditions. De-energizing equipment, following adequate lockout/tagout procedures, and verifying the absence of voltage are key to accomplishing this. As industry strives to make the practice of de-energizing equipment before performing electrical work standard practice, verifying the absence of voltage has become one of the most frequent tasks performed by qualified electrical workers.

Behind the Scenes of IEEE 1683: A Look into the Creation of a Standard

Electrical equipment installations and system designs that comply with well-known consensus standards and national codes will meet or exceed minimum guidelines for safety and reliability. However, many within the industry believe that further attention should be paid to the principles of safety by design and prevention through design. In response, IEEE Standard 1683 [1], has been written to address electrical safety for low-voltage motor control centers (MCs), and similar standards are in development for other types of equipment. IEEE 1683 is the first IEEE standard developed to specifically address equipment design, selection, and installation practices with an emphasis on methods to reduce exposure to shock and arc-flash hazards. This article summarizes the history and reasons that led to the development of IEEE Standard 1683 and provides an introduction to its application for safer, low-voltage MCs.

Arc-Flash Incident Energy Variations: A Study of Low-Voltage Motor Control Center Unit Configurations and Incident Energy Exposure

There has been significant progress in arc-flash research in recent years, but there has been little focus on how the internal configuration of equipment affects the released incident energy. The relationship between low-voltage motor control center (MCC) unit configurations and incident energy exposure resulting from an arc flash is examined in this article. Testing was conducted using actual MCC structures and units. The design of experiment (DOE) methodology was used to analyze several MCC configuration variables, including unit type, unit size, percent fill of unit, power wire size and length, location of the unit within the structure, and their relationships to incident energy as well as arcing duration and arcing current. The results from 24 arcing tests were analyzed, and the magnitude of incident energy measured during the events was observed to be related to the percent fill of components within the units and properties of interior unit surfaces.

Considerations in Applying Arc-Resistant Low Voltage Motor Control Centers in Refining Environments

Arc-resistant equipment is becoming increasingly common in North America and in the petrochemical industry. Traditionally, low voltage motor control centers (LVMCCs) designed to National Electrical Manufacturers Association (NEMA) standards have not been addressed in arc resistant testing guides. This paper describes how arc resistant principles can be applied to the LVMCC, which is constructed according to Underwriters Laboratory 845 (i.e., the NEMA ICS 18 600V class of equipment). A brief overview and history of applicable arc resistant testing guides, specific considerations for adapting internal arcing fault test procedures to LVMCCs, and considerations for specifying and installing arc-resistant LVMCCs in a refining environment are discussed.

A study of ARC flash incident energy variations based on MCC unit configuration

There has been significant progress on arc-flash research in recent years, but there has been little focus on how the internal configuration of equipment affects the incident energy released. The relationship between low voltage motor control center (MCC) unit configurations and incident energy exposure resulting from an arc flash is examined in this study. Testing was conducted using actual MCC structures and units. The design of experiment methodology was used to analyze several MCC configuration variables, including unit type, unit size, percent fill of unit, power wire size and length, location of the unit within the structure, and their relationships to incident energy as well as arcing duration and arcing current. The results from 24 arcing tests were analyzed and the magnitude of incident energy measured during the events was observed to be related to the percent fill of components within the units, and properties of interior unit surfaces.