Over the years recently there has been more emphasis on arc flash due to injuries. You can search on it. The issue is the potential for arc flash when the control panels are open and powered by the electrician which can cause clothing to catch fire. It's not so much an issue of containing an arc flash within the enclosure, a fire enclosure should do this regardless.
I asked our NRTL test engineer about arc flash warning label requirements a few months ago and he pointed out that wording in NFPA 70 states that arc flash warning labels are to be applied on site during machine installation. There is not a requirement for the manufacturer to apply the warning. I don't have my copy of NFPA 70 in front of me but I recall I confirmed the wording. I recall I also confirmed the same on the OSHA web site. These labels can be purchased off the shelf. NFPA-79: Sec. 16.4 requires the SCCR of electrical control panels to be put on the product nameplate. UL 508A: Supplement SB has instructions for determining SCCR. If your product doesn't contain an electrical control panel and no internal branch circuits you may not need the rating. I've only had an NRTL certify to NFPA 79 for field labeling/marking. -Dave -----Original Message----- From: Kunde, Brian [mailto:[email protected]] Sent: Monday, November 24, 2014 3:29 PM To: [email protected] Subject: [PSES] Arc Flash Requirements NFPA 79 Our company produces Laboratory Equipment. We design to the IEC/EN/UL 61010-1 series of standards and the NFPA 70 NEC. Some of our instruments can be quite large; slightly bigger than an upright piano. They typically are powered by 230VAC, 20A to 50A branch circuits. It is typical that our instruments are installed near or in a heavy industrial environment even though they are not considered Industrial Machines. They are sometimes mistaken as Industrial Machines. Recently, we have had customers ask the following questions about our instruments: * Proof that the electrical system complies to NFPA 79. * Are the electrical enclosures marked for arc flash hazard per NFPA 79? * What is the Short Circuit Current Rating (SCCR) of our instruments? Typically we simply reply that our instruments are not Industrial Machines and that is that. However, if there is information we can provide that would be helpful, we would like to do so. I can see where our customer may wish to power our instrument from a circuit that is capable of producing very high short circuit current (SCC). If this exceeds the 5kA rating of our internal Supplementary Protection Device, then our customer would have to supply a Brach Circuit Breaker that can handle the SCC. High SCC can also cause a concern for Arc Flash. I do not know the requirements of NFPA 79 and how it affects Arc Flash. For instance, since our chassis meets the mechanical requirements called out in IEC 61010-1, is it likely that our chasses will contain the arc flash hazards? Is there any part of NFPA 79 that could apply to our instruments; to the mechanical or electrical system? Has something changed recently which would explain why we are now receiving these type of questions? Thanks for any input or advice. The Other Brian ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
