Intelligent Power Today Magazine

Answering frequently asked questions about arc flash relays

BY BOB ZWEIFEL, Littelfuse

The dangers of an arc flash incident—burns, blast, molten metal ejected at ballistic speeds—are by now familiar to every electrical worker. Most electrical professionals have read about strategies to minimize arc flash hazards, including arc flash relays. Now many of them are seriously considering integrating arc flash relays, but they have many questions about how to install this unfamiliar technology and exactly what the benefits will be.

Electrical Source Magazine and Littelfuse, based on the company’s frequently asked questions, offer some insight on how to apply these valued...

Over the last few decades, arc-fl ash hazards have been a significant concern for many electrical workers and employers. Many methods have been developed through the years to assess incident energy.
The most common is that of the IEEE 1584, Guide for Performing Arc-Flash Hazard Calculations. These equations have remained the same since the standard was first published in 2002. Based on the results of more than 1,800 tests, the 2018 edition of the guide provides new formulas that are both more accurate and more complex. These formulas also take more parameters into account now, including the conductor orientation at...