Edward Murphy is famous for his law that states: “Anything that can go wrong will go wrong.” When performing an arc flash study, Murphy’s Law becomes very important if assumptions are made about this rare but potentially deadly event.
The first step in conducting an arc flash study is to obtain the data necessary to accurately represent the electrical system. Equations defined by IEEE 1584–IEEE Guide for Performing Arc Flash Hazard Calculations are at the heart of most studies and require a lot of data.
Without warning, smoke rolled out from under the tires as they squealed against the pavement with the brakes locked up. The big truck seemed to come from nowhere. It felt like an eternity; although it was really only a matter of seconds, then … CRASH!
The surface area of the earth is approximately 197 million square miles, and IEEE 1584—IEEE Guide for Performing Arc-Flash Hazard Calculations has been covering more of it every day since it was first published almost 11 years ago.
“Kill the Circuit.” This phrase is a colorful way of saying de-energize the circuit. Easy enough—just open a switch or other protective device and the circuit is “dead.” It should then be safe to work on, right? Wrong! Simply opening a switch does not guarantee the circuit is de-energized. Really?
The 2012 Edition of NFPA 70E, the Standard for Electrical Safety in the Workplace, has made a significant change to the information requirements for arc flash warning labels.
According to Section 130.5(C), the following is now required: