More and more people are hearing the term, Arc Flash Analysis, and wondering what to do about it. Caterpillar has an OnLine Community where such things are raised and discussed. This response showed up recently on the forum...and it makes sense! At the bottom of the article is the link to the Caterpillar site.
A few points on the arc flash analysis.
Yes, a lot of people are still hearing it for the first time. It was only in 2002 that NFPA & IEEE put the standards together to define how an arc flash should be done. OSHA has indirectly adopted the standards by stating that workers must be warned about electrical hazards and the proper PPE to wear and referencing NFPA. The only way to properly warn the workers of the threat level and required PPE is to do an arc flash analysis with the exception of using the NFPA 70 E tables. The problem with the NFPA 70E tables is that in order to use them, you must already know the short circuit current and clearing time of your protective devices and the results of that must fit within the parameters of the chart (read the footnotes). We have never found anybody who can actually use the charts as they were designed, although they are a good reference point for PPE safety if you haven't got an arc flash analysis done yet and need to approach an energized part.
Getting an arc flash analysis done is not cheap internally or externally, but it's a heck of a lot cheaper than the damages if there is an accident and the analysis wasn't done. OSHA has been laying down heavy fines in these cases, not to mention the legal and insurance costs.
No, you don't need to be a PE or outsource the arc flash analysis, however, there are a lot of challenges in doing an analysis internally, the start of which is putting money up front for the software and learning to use it which can cost $10K - $30K and several weeks for that process alone. The bigger problem, however, is the simple inexperience of doing an arc flash analysis. It takes literally a dozen jobs under the direction of a PE with a lot of arc flash experience to to do a job right. The biggest problems we see with self- analysis are; a) data collected isn't accurate b) analysis is only done at top voltage loads, not the lowest, which can be more dangerous c) lack of ability to provide recommendations on how to make minor changes to something like the setting of a breaker to take it from Cat 4 down to Cat 2. We see companies buying sets of expensive Cat 4 PPE based on the outcome of the analysis when really, a few minor adjustments or a change in a breaker might eliminate both the need for the Cat 4 equipment and more importantly, reduces the hazard for their employees.
And here is the million dollar question (or $9 million question as the estimated cost of an arc flash accident involving serious injury). If you do the analysis yourself and there is an accident and a forensic engineer comes in and finds out that the analysis was done wrong, who do you think is going to be held liable?
If you have any questions, feel free to contact me or you can get more information on our web sites www.martinarcflash.com or www.martechnical.com
Jim Schuster, VP, Martin Technical
Caterpillar OnLine Discussion Link: https://caterpillar.lithium.com/t5/Power-Generation-Regulations/Arc-flash/m-p/254/highlight/true;jsessionid=C1C6345A93FA1AC268E7E08671D0A1EE
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