Integrating Arc-Flash Analysis: A Look at Protective Device Coordination

This article introduces a novel method for integrating arc-flash analysis with protective device coordination on time-current coordination (TC) plots. A new concept, called the human damage curve (HDC), is included in the coordination process, which relates directly to calories/cm² energy levels of personal protective equipment (PPE). Each curve in an HDC family holds to a set of consistent arc-flash assumptions based on those found in the National Electrical Safety Code (NESC) and IE 1584 standards. That set of assumptions includes values for the working distance, voltage level, arc gap width, open air/cabinet conditions, and the full consideration of escape time.