One of the very major causes of accidental arc flash is that the people in the area did not really understand what they were doing. NOT in regard to arc flash protection, but they did not fully understand what the task involved to be done safely. I relize that this flys full in the face of a number of groups that claim that any individual can do any task, and if they fail it is somebody else's fault for not training them.
Accidental arc flash is separated from equipment failure arc flash in this area because equipment failure arc flash may also happen when nobody is doing any work related to the system creating the flash. Of course it does include faults caused by incorrect assembly of components at some previous time. But equipment failure arc flash can injure a passerby who was not involved at all.
And there are mechanisms available to provide a higher impedance to the very fast current rise that is charateristic of arc flash, and also the source of many of it's damaging effects. The mechanism is in the process of being patented, which is all that I can divulge about it. But it does work, I have seen the videos.
Thanks for replying, Stewart. I didn't know that stat, but I did know how serious even short exposure can be. My heart went in my throat when he told me. He's being pretty nonchalant about it, although he went through a lot of pain in the doctor's office with whatever drops they used to treat him. Thanks for your good wishes. I'm amazed, and unhappy, about the lack of standards and guidelines.
95% of people struck by arc flash end up with permenant eye sight loss. Despite the guidelines provided by OSHA, industries and business owners have not created any specific safety guidelines within their facilities to protect and to safe their workers.
Thanks for writing about this problem. My 24-year-old nephew, who's done a fair amount of welding maintaining and repairing the heavy lifting equipment he operates for his job, recently told me about an arc flash accident where nothing got damaged except his eyesight (temporarily it seems) since for some reason he wasn't wearing goggles. Naturally, I gave him a lecture about it, but what really surprised me was the lack of controls in place at his workplace. No one was insisting he wear goggles, and of course he wasn't experienced enough to realize how bad the hazard can be.
It's better that the circuit is dead, rather than becoming a dead engineer.
It's interesting to compare the US and UK/European approaches to achieving safety. In the UK the use of personal protective equipment is a *last* resort (at least it's meant to be). That is particulalrly true when the consequences of an incident can be so high. The authorities would ask why the circuit wasn't made dead first.
Good equipment design, as you say, to divert any arc flash is also important when PPE can be cumbersome and ignored.
Great article although I would add one more thing to the list:
Although this may fall under neccesary preventative measures since it should be in place up front to prevent occurences, I am just being a bit more specific: Design and equipment configuration choices that reduce arc flash hazard.
Transfers the control of a large number of motion axes from one numerical control kernel to another within a CNC system, using multiple NCKs, and enables implement control schemes for virtually any type of machine tool.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.