If the product powered from a certified SELV, power limited supply will be used or installed in a workplace in the US, then it is subject to OSHA NRTL approval requirements and the mixer would be required to be certified by an NRTL. OSHA regulations do not provide an exception to the approval requirements based on the voltage/current from an external power supply.
If you have any questions, feel free to contact me directly. Kevin Robinson Engineer & Senior Auditor OSHA NRTL Program 202-693-1911 robinson.ke...@dol.gov On Nov 16, 2012, at 7:21 PM, Chuck McDowell <chu...@meyersound.com> wrote: > In America, a few years ago at Lucent, we built a DSL device that was > remotely powered by a separate power supply with a NEC ANSI/NFPA 70 Class 2 > DC output. The power supply had a NRTL safety marking, and as you suggest, > the DSL device itself did not carry a NRTL safety mark, only EMC and Fcc > approval marks. > > Chuck McDowell > Meyer Sound Laboratories Inc. > > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Aldous, Scott > Sent: Friday, November 16, 2012 8:36 AM > To: Mcburney, Ian; emc-p...@ieee.org > Subject: RE: Product safety requirements > > You would need to make sure that the output of the power supply is a Limited > Power Source in order to deal with fire hazards. The nameplate output ratings > are necessary but insufficient information to determine if a fire hazard may > be present. Also, it is possible that your regulators (maybe just the boost) > could produce voltages internally that would be considered a shock hazard, > which would require evaluation of the output circuits as SELV. There are a > wide variety of DC/DC converters commercially available that have SELV inputs > and SELV outputs which nonetheless still have 3rd party safety > certifications. You should be able to find a certified one OTS (or multiple > converters) that will work for you if you don’t want to deal with the > certification piece yourself. Maybe that defeats the purpose of what you are > trying to do since you could just as easily find OTS certified AC/DC power > supplies. > > Technical considerations aside, you could always run into trouble with any > given local authority or customs official wanting to see certification on > your mixer, not just on the power supply that connects to it or that it ships > with. > > Also, you should be aware that most notebook power supplies nowadays have > more than just the power output pins – they have feedback signals that are > intended to keep the supplies in a low power consumption mode when the > computer is in the off state in order to comply with various efficiency > regulations. If you don’t provide the right signal, you won’t get power out > of them. > > Scott Aldous > Compliance Engineer > AE Solar Energy > > +1.970.492.2065 Direct > +1.970.407.5872 Fax > +1.541.312.3832 Main > scott.ald...@aei.com > > > 1625 Sharp Point Drive > Fort Collins, CO 80525 > > www.advanced-energy.com/solarenergy > > > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Mcburney, Ian > Sent: Friday, November 16, 2012 8:24 AM > To: emc-p...@ieee.org > Subject: Product safety requirements > > Dear Colleagues > > We are a manufacturer of audio mixing consoles with a range that varies from > A4 size up to large 2m long 2 man lift consoles. > Most have internal ac/dc power supplies. > We are researching changing the way we power are future products to > rationalise the psu range as worldwide approval costs increase. > One of the options is to purchase 60-80W PC laptop power supplies and power > the smaller mixers from the DC output of the external laptop supply. > The DC output voltage from a laptop PSU is typically 19V. However; most > mixers require typically +/-15V, +10V & +48V internal voltage rails. > We propose to buck regulate the +/-15V and +10V rails & boost the +48V rail > from the 19V DC input. > If the total power consumption of the mixer was no more than 80W and the +48V > was current limited to no more than 1 Amp, would the mixer require approval > testing for north America or any other country as the input voltage would > only be 19V DC. > Obviously the external ac to dc laptop power supply would have all the > necessary approvals; probably to IEC60950 and be class 1 construction. > > Your opinions would be appreciated. > > Thank you in advance; > > Ian McBurney > Design Engineer > > Allen & Heath Ltd > Kernick Industrial Estate > Penryn, Cornwall > TR10 9LU > United Kingdom > > +44 (0)1326 370121 > > ian.mcbur...@dmh-global.com > www.allen-heath.com > A DMH Pro Company. > > - > ---------------------------------------------------------------- > 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 > <emc-p...@ieee.org> > > 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://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <emcp...@radiusnorth.net> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > > > This message, including any attachments, may contain information that is > confidential and proprietary information of Advanced Energy Industries, Inc. > The dissemination, distribution, use or copying of this message or any of its > attachments is strictly prohibited without the express written consent of > Advanced Energy Industries, Inc. > - > ---------------------------------------------------------------- > 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 > <emc-p...@ieee.org> > > 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://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <emcp...@radiusnorth.net> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > > - > ---------------------------------------------------------------- > 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 > <emc-p...@ieee.org> > > 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://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <emcp...@radiusnorth.net> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > > ouglas <emcp...@radiusnorth.net> > Mike Cantwell <mcantw...@ieee.org> > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
