Ian That's a very good question!
The only other things that I can currently think of are: - The agency does not (want to?) accept the UL Recognition (not Listing, I suspect) for "business political" reasons because UL is a competitor (and AFAIK, there is no compelling legal reason why they have to where components and materials are concerned - but it's common business practice to do for the sake of relationships with their own customers), - &/or either the project engineer or his senior engineer are "playing very safe" and don't want to trust anything they think they can't be 150% sure of (and some agency engineers don't have too much experience of dealing with design approaches which are not exactly in line with what the standard appears to mandate!. They are also bound by the defined operating procedures of their agency, and this can be very frustrating in its own right - like others here, I know because I have "been there" :-( ) Either way, have you tried getting a clear explanation from the agency as to exactly why they are requiring this "extra" testing? Regards John Allen Compliance with Experience W.London, UK. -----Original Message----- From: McBurney, Ian [mailto:ian.mcbur...@allen-heath.com] Sent: 13 December 2013 13:55 To: John Allen; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] Cooling fan safety query John; I agree the airflow rates will vary with applied voltage and blade profile but if the product continues to function "safely" with a stalled rotor why does it have to be listed in the critical component list. Regards; Ian McBurney Design & Compliance Engineer. Allen & Heath Ltd. Kernick Industrial Estate, Penryn, Cornwall. TR10 9LU. UK T: 01326 372070 E: ian.mcbur...@allen-heath.com -----Original Message----- From: John Allen [mailto:john_e_al...@blueyonder.co.uk] Sent: 13 December 2013 13:31 To: McBurney, Ian; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] Cooling fan safety query Ian I think the critical factor may be the airflow rates at the reduced voltages as this may well vary between various ostensibly similar fans of the same nominal voltage. The actual airflow patterns from the outputs of the various fans may also differ due to differing blade profiles, etc. Regards John Allen Compliance with Experience W.London. UK -----Original Message----- From: McBurney, Ian [mailto:ian.mcbur...@allen-heath.com] Sent: 13 December 2013 11:05 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Cooling fan safety query John; I believe the fans are listed for the flammability of the plastic body but I may be wrong. Ian McBurney Design & Compliance Engineer. Allen & Heath Ltd. Kernick Industrial Estate, Penryn, Cornwall. TR10 9LU. UK T: 01326 372070 E: ian.mcbur...@allen-heath.com -----Original Message----- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: 13 December 2013 10:34 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Cooling fan safety query In message <80f690de07894e049b221728b4a99...@dbxpr07mb206.eurprd07.prod.outlook.com> , dated Fri, 13 Dec 2013, "McBurney, Ian" <ian.mcbur...@allen-heath.com> writes: >We have to use alternative fans due to supply issues and this incurs >considerable test agency costs as the agency won?t accept a >manufacturers range of fans without testing each one. On what grounds are they re-testing when the fans are UL-listed? -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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