Technical Articles

NFPA 70E and Arc-Flash Calculations Above 15 kV Question: Can IEEE 1584 be used for higher voltages, such as 23 kV or 34.5 kV systems? Short answer: No. This is a very common questions I receive during my training about NFPA 70E Article 130.5 (Arc-Flash Risk Assessment) and IEEE 1584. The IEEE 1584-2018 equations for incident energy, arc-flash boundary, and arcing current are only validated for systems from 208 V through 15 kV. Once you go above 15 kV, IEEE

Question:Some arc-flash labels list the arc-flash boundary in inches, others in millimeters or meters, and some even show odd values like 3.4 feet. On top of that, IEEE 1584 uses joules per square centimeter (J/cm²), but PPE ratings are in calories per square centimeter (cal/cm²). Why is there so much inconsistency on NFPA 70E arc flash / equipment labels? Answer:It looks messy, but there’s a logical reason behind it. The short version is this: IEEE 1584 is based on metric

For nearly two decades, I have been closely associated with the UK’s—and Europe’s—foremost authority on arc flash and electrical safety: Electrical Safety UK (ESUK). Based in Rotherham (Sheffield), England, ESUK has been at the forefront of advancing electrical safety practices for over twenty years. I have had the privilege of contributing to this journey from its early days and continue to serve on the company’s board. My association with ESUK began close to its inception, when its founder, Mr. Mike

Question Most arc-flash labels as required by NFPA 70E appear with the word “WARNING” on an orange background. However, I occasionally see red labels and even green labels.So… what color is correct? Answer The technically correct answer is: it depends. To understand why, we need to separate what NFPA 70E requires, what ANSI standards define, and what has become common industry practice. NFPA 70E and Arc-Flash Labels NFPA 70E requires that electrical equipment likely to require examination, adjustment, servicing, or

IEEE 1584, NFPA 70E and the “2-Second Arc Duration” Myth Question:I’ve heard that an arc flash can’t last longer than two seconds. Is that true? Short answer:No! An arc flash can absolutely last longer than two seconds. Neither IEEE 1584 nor NFPA 70E says an arc flash is physically limited to two seconds. The two-second value is an assumption used for exposure time, not a limit on how long an arc can actually exist. This misunderstanding comes from a statement

Question: Arc Flash Boundary – Safe? Since NFPA 70E does not require arc-flash PPE outside of the arc-flash boundary, does that mean it’s a safe place to stand? The Short Answer: I would not stand there – without some protection! – Really? Yes, but I have the advantage of seeing many staged arc flash events in the lab so I know what it can do.  What NFPA 70E Actually Says About the Arc-Flash Boundary Let’s start with the basics. NFPA

Electrical safety isn’t theory—it’s protection for people, equipment, and uptime. For more than 40 years, Jim Phillips has helped engineers, electricians, and safety professionals turn the NFPA 70E Standard for Electrical Safety in the Workplace into practical, actionable safeguards that reduce incidents and strengthen compliance. At Brainfiller, Jim leads some of the industry’s most trusted NFPA 70E training programs, known for converting complex standards into proven, field-ready procedures. What Is NFPA 70E and Why It Matters Developed by the National