Arc resistant equipment for low voltage motor control center applications

Abstract

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.Index Terms -Arc flash, arc resistance, device limited arc resistant rating, duration arc resistant rating, internal arc fault, low voltage motor control center.

Considerations in applying arc resistant low voltage motor control centers in refining environments

“…The test method that must be used is based on the type of protective device used to obtain the rating: no protective device, current limiting devices, and duration limiting devices. A brief summary is included here, but more detailed information can be found in [2] and [16].…”

“…When testing, it is important for the manufacturer to construct test samples so that worst case scenarios can be tested; due to the configurable nature of the LVMCC, it may be necessary to test multiple compartments and configurations (e.g., bus compartments, feeders, starters, etc.) [16]. Users and manufacturers should work together to ensure that the arc resistant LVMCC has been properly tested and evaluated in a manner that is suitable to the specific application.…”

“…If this is the case, the rating for each compartment should be clearly marked There are no guidelines or calculations for extrapolating test data for longer arcing durations at lower currents or voltages, so the requirements on the rating label should not be exceeded. [2] [16] The user should ask for a test certificate or letter of attestation to verify that the claims of the manufacturer are valid and that all tests conformed to an internal arcing test procedure (e.g., IEEE C37.20.7-2007).…”

Arc flash study and remediation project in a Midwestern pulp and paper mill

“…This facility has recently installed a 9-section lineup of arc resistant MCC to evaluate for future projects. [3] …”

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

“…[16]. Users and manufacturers should work together to ensure that the arcresistant LVMCC has been properly tested and evaluated in a manner that is suitable to the specific application.…”