Warning! No Arc Flash Hazard Exists!
Jim Phillips, P.E., BScEE, IEEE Life Sr. Member, MIET
Brainfiller.com | Electrical Power, Arc Flash, Electrical Safety Training | IEEE 1584 Arc Flash Vice Chair | NFPA 70E Committee | International Chair IEC TC 78 | NEC Committee
I’m sure that title raised a few eyebrows, but before you send me an email telling me how I got this wrong, hang in there for the rest of the thought.?I receive questions about this phrase on a pretty regular basis.?It’s no secret that 1.2 cal/cm2?is the generally accepted value of incident energy exposure where the onset of a second-degree burn may occur. This is also the value that triggers the need for arc rated clothing and protective equipment. However, having a prospective incident energy?below?1.2 cal/cm2 can cause confusion as some will place the phrase “NO ARC FLASH HAZARD EXISTS” on the arc flash label as a result.?When I ask why this phrase is on the label, I receive the response that it’s because the incident energy is less than 1.2 cal/cm2.?– BEEP – Wrong Answer!?If the prospective incident energy is less than 1.2 cal/cm2, remember that is at the working distance and it only means that it is below the threshold where the onset of a second-degree burn may occur.?It does NOT mean there is no injury possible. What about first-degree burns??What about the hands or other parts of the body being closer than the working distance??What about…?You get the idea.?There IS still a hazard it is just not commonly considered a major hazard that requires arc rated PPE?at the working distance.
I am asked about using this phrase so often that awhile ago I decided to ask a more general survey question about arc flash hazards at 208 Volts at the website?www.ArcFlashForum.com .?I was surprised to see almost 20% of the respondents to the survey indicate they did not believe an arc flash hazard exists at 208 Volts.?The survey and discussion are found here:??https://brainfiller.com/arcflashforum/viewtopic.php?f=33&t=5416 ?The working distance is very important because it is the distance from the arc flash source that is used to calculate the incident energy where a worker’s head and torso would likely be located. This makes understanding the working distance a very important part of an electrical safety training program.?Just because the incident energy is listed as less than 1.2 cal/cm2?at 18 inches for example, doesn’t mean it will be that low for hands and other parts of the body that are closer. It increases as the working distance decreases.?I can hear this scene being played out in a legal setting. Attorney: “I am sorry to hear that you received a burn injury on your hand but why where you not wearing arc flash protection?” Response: “Because the label stated – No Arc Flash Hazard Exists”?Really? Fade to black, game over.
Electrical Consultant//Project Management//Master Electrician//Senior Project Manager//Project Specialist
1 年It's great to see this information finally getting out there more often. Thank You
Electrical Safety Consultant at the Palo Verde Nuclear Generating Station
1 年Excellent point about the working distance as the point of demarcation for the IE information on the label, which is normally 18" for most low voltage equipment. What many forget is any part of the body between the arc source and 18" will be exposed to a level of IE north of the label information. Keep up the great job Jim.
Expert - Electrical Engineer @ BASF
1 年Our company still requires PPE from 0-1.2 for this reason. Why? Cause I prefer you not get hurt. Have been putting more emphasis during training on understanding working distance and how incident energy increases as you get closer. Keep providing the education please.
Chief Electrical Engineer ESIPAC & Technical Director Transmag
1 年As always Jim, so articulatory accurate in every sense. Arc Flash isn't Russian Roulette... but it can be just as devastating. Arc Flash PPE is a safe guard against the unexpected... As Engineers, one of your mottos will always have been....'expect the unexpected' Wear the kit, miss the hit!!
Electrical Safety | Arc Flash | Electrical Engineering
1 年Showing photos of such injuries below 1.2 cal/cm2 during training really helps people to understand the problem and the need for adequate protection, especially for the hands and eyes.