The table provides the PPE for incident energy exposure > 12 cal/cm2, does that mean any exposure of >40cal/cm2 can use that table as well? I thought from previous version of standards, it says that PPE doesn't exist for anything over 40cal/cm2.

Nothing in the standards ever said nothing existed. There is one line in an informational note (not part of the Code) that says that a heightened level of awareness should be used but there is no explanation as to how to implement this or what it is intended to mean.

At one time (1990's) historically 40 cal/cm^2 was a cutoff. However you can buy 100 cal/cm^2 ATPV arc flash suits from multiple vendors now and I think Oberon even has stuff that is beyond 100 cal/cm^2 now.

Either way, this is getting pretty ridiculous. You should also be following ANSI Z10 "hierarchy of controls" which is also explicitly pointed out in the 2015 edition. That is, try to find ways to eliminate the hazard. There has been published studies showing that chemical plants can be designed and built on a maximum 8 cak/cm^2 standard. You can't do this easily starting with existing equipment but it's a worthwhile goal nonetheless. Out of around 2000+ buses in a recent analysis for a site that I did, only about 25 or so exceeded 40 cal/cm^2 that weren't simply a numerical anomaly and only a small amount could not be addressed by reducing the trip times on the breakers.

Is "danger" label still acceptable based on new version of CSA Z462? The table 4B and 4C only gives the category up to 4, however the Annex Q still allow danger label. And table H2. and H3 don't say anything about the category but just incident energy. Interesting thing is the PTW32 still gives dangerous category for one above 40cal/cm2.

The "DANGER" label was never allowed no matter what the examples show. ANSI Z535 uses the signal word "DANGER" to indicate that there is an immediate danger to life or a life altering injury such as one that requires hospitalization. The word "WARNING" applies to hazards which have the same consequences as DANGER but in which they are not likely to happen or it requires an effort on the part of the worker to cause the incident.

The word "DANGER" belongs on warning signs around the augers in snow blowers, wood chippers, on industrial fan housings, and in vessels that contain highly hazardous gases or liquids, or any similar sort of danger that comes down to the fact that entering a space or removing a cover/guard will more likely than not result in a serious injury or fatality. For everything else, the proper word is "WARNING". Arc flash incidents are rare but can result in serious injury or even death. Thus the proper signal word is WARNING.

I know that SKM incorrectly implements the "DANGER" keyword and it takes an effort to fix the label tables to eliminate this screw up. And I realize that lots of consulting firms screw this up as well. But the labelling standards that are referenced cannot be more clear on this issue.

The contents of the label must be considered when discussing the use of Danger on the label. Labels that contain both the arc flash hazard and shock hazard are using Danger as it takes very little current to cause death or other injury.

I don't see a problem to put danger label on equipment where the incident energy could be potentially as high as 40cal/cm2. For wearing heavy PPE to do the interactive operation is not good and safe practice. We still recommend electrician to de-energize the service if they need to do the work.

There are two huge problems with using the incorrect signal word. The first one is just that...it's the wrong word and it is not following the standard. If you're not going to follow the standard anyways, then why even have a standard.

The second and more egregious problem is what happens in the field. If you use two clearly obvious and different labels then workers will attribute some sort of magical difference between the equipment labels. Paranoia sets in and they start treating the "DANGER" label as something special when it's not. It propagates a bunch of tribal knowledge and myths that aren't true when they get trained with general knowledge about the signal words DANGER, WARNING, NOTICE, etc. So then when this tribal knowledge gets challenged and you start saying that it's OK to open the door on electrical equipment with a DANGER label if you take certain precautions, it diminishes the meaning of the word and then becomes a big problem when dealing with other types of equipment which are properly labelled and hinting at the idea that it is OK to open the covers on equipment that is labelled DANGER as long as you take some sort of precautions even while it is energized/active when in fact it is never safe to do so.

So you set up electrical workers in particular to act like cowboys and increase the likelihood of injury with nonelectrical equipment. And if you don't think this doesn't happen, then you haven't been paying attention to what happens out in the field/factory floor when there is confusion and/or ambiguity in labelling that is specifically caused by not following standards.

Again...if the standards have no meaning, then why do we have standards. If they do have meaning, then we need to follow them.

I am a consulting engineer with hundreds of arc flash projects nationally and internationally.

I place Dangers! labels on equipment of 40 cal/cm^2 or larger.

I know this is NOT a NFPA 70E requirement. This standards says that you have to take special precautions to work on equipment of more than 40 cal/cm^2, NOT to avoid not to prohibit work on this equipment.

I also know that there is a non-written standard that energies of 40 cal/cm^2 or more should be labeled as Dangerous with a red label. ALL the studies I have seen from other consultants and that I know of, are labeling these high AFIE with a Dangerous red label.

I also understand PaulEngr's point of view to be the correct TECHNICAL interpretation regarding the quoted labeling standard. I am positively impress in PaulEngr's dedication and knowlede about this subject, especially on this willingness to spend a large amount of his time answering this forum questions and giving us is important point of view.

But we do not leave in a black and white world. I believe that if PaulEngr looks deeper, he might also find some inconsistencies in his decisions regarding the standards (there are many more factor to consider).

I still will print Dangerous labels (knowing that there are some inconsistencies with other labeling standard) because I don't believe that in this particular case (arc flash incident energy) the misused of this term (according to the labeling code) will have such a bad effect as described by PaulEng and the benefits it brings are far more positive than negative. As in everything a believe, I could be wrong. More information can change my mind. Until then, I will print Dangerous labels, following this unwritten standard and believing that it brings more good that evil.

I am open for discussion on this issue with a true thirst of knowledge and elightment.