View Full Version : Does this carry more weight?
PDS_Dave
02-07-2008, 06:50 AM
As most forum members know, the requirement for arc flash analysis has existed in the 70E for some time, and the requirement for device labeling has existed in the NEC since the 2002 revision. 29CFR1910.132(d)(1) references a hazard assessment, a requirement that an arc flash analysis meets, and yet people still argue the "requirement".
The NESC is an IEEE publication but is also an ANSI standard. This being the case, will 410A3 carry more weight than the 70E requirement? Are people finally going to understand what "required" means? I am anxious to get answers from folks in the know, so please feel free to respond.
WDeanN
02-11-2008, 02:34 PM
It is my understanding that although a full analysis certainly meets the requirement, it is not necessary to perform an analysis.
The tables can certainly be used in place of a full analysis, provided the guidelines are met. (I know, I know: How do you know you've met the guidelines without performing a study?:confused: I don't think that has been looked at enough, and it still is not necessary to perform a full study to know if you meet the requirements. Some basic calculations can tell you this.) The 70E method is also based on Ralph Lee's equations. Do you also follow this?
In short, there is no REQUIREMENT for a full study. It is definitely recommended, however.
In the publication that you metioned above:
Section 410.A.3 states:
“Effective as of January 1, 2009, the employer shall ensure that an assessment is performed to determine potential exposure to an electric arc for employees who work on or near energized parts or equipment. If the assessment determines a potential employee exposure greater than 2 cal/cm² exists (see Neal, Bingham, and Doughty ), the employer shall require anticipated level of arc energy.”
[B]Courtesy of IEEE—”as called upon as an industry consensus under OSHA 1910”To order your copy of this publication, go to: http://standards.ieee.org/nesc/nesc.html
I believe that it is hard to argue with this statement, wouldn't you?
apowerengr
08-17-2008, 12:25 PM
Utilities are the only entities subject to the NESC so this rule should not have any impact on facilities not in the control of utilities.
The new NFPA 70E-2009 apparently contains language related to NEC 110.16 which will require labels having either the flash protection boundary or the arc energy stated specific to the location of the label. That should give some push to performance of arc flash studies in the design of new facilities.