Do not necessarily disagree, but there are some problems. Am guessing that this is referencing 29CFR1910.303. Also have this excerpt from an OSHA memo in my database:
"The testing standard will typically specify how the product is to be marked or labeled and what instructions for installation and use must be provided. Thus, an employer would be in violation of 29 CFR 1910.303(b)(2) if its installation or use of equipment, such as energy management equipment, is not consistent with the NRTL-required markings and labeling or the installation and use instructions required for that equipment." So herein lurks a common problem - NRTL writes ITE report for Class III equipment where conditions of acceptability indicate use of a source certified as an inherently limited Class 2 'LPS'(probably UL1310/CSA 223 source). NRTL says no agency mark needed. But administrative law can be interpreted for mandatory 'mark', but the government has, on several instances, say that marking requirements are the scope of the NRTL. Also note that article 725 of NEC is oft used by an AHJ inspector to determine if the voltage/power/energy level indicates that no further consideration for safety of equipment is necessary, where the install is not permanent and not part of building wiring. Choose your poison. Brian -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Kevin Robinson Sent: Friday, November 16, 2012 5:34 PM To: Chuck McDowell Cc: Mcburney, Ian; [email protected] Subject: Re: Product safety requirements 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 [email protected] On Nov 16, 2012, at 7:21 PM, Chuck McDowell <[email protected]> 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: [email protected] [mailto:[email protected]] On Behalf Of Aldous, Scott Sent: Friday, November 16, 2012 8:36 AM To: Mcburney, Ian; [email protected] 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 [email protected] 1625 Sharp Point Drive Fort Collins, CO 80525 www.advanced-energy.com/solarenergy From: [email protected] [mailto:[email protected]] On Behalf Of Mcburney, Ian Sent: Friday, November 16, 2012 8:24 AM To: [email protected] 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 [email protected] www.allen-heath.com A DMH Pro Company. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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