The UL interpretation is: Pollution Degree 2, based on the IP66 rating. I think EN60950 3rd Ed., clause 2.10.1 is very open to interpretation - I can make a great case that my power supply inside the enclosure is a subassembly (what else could it be?). Also, that subassembly is sealed against moisture or dust, as evidenced by the type test performed to a harmonized standard. I do understand the intent of PD 1, though, as others have responded in so many words, "that's for things that are potted". We're designing to PD 3 spacings - I've already played devil's advocate as you did. I just wanted to hear a few opinions. Doug
-----Original Message----- From: John Juhasz [mailto:jjuh...@fiberoptions.com] Sent: Monday, April 02, 2001 1:35 PM To: Massey, Doug C.; 'IEEE Forum' Subject: RE: 950 Pollution degree detirmination Doug, While I would tend to agree that this may be acceptable, and I would too like to see some sort of 'official' determination on this (I may have a similar situation arise in the next couple of months), I would like to play devil's advocate for a moment to further this discussion . . . As you quoted " . . . EN60950 3rd Ed., clause 2.10.1 defines Pollution Degree 1 " for components and subassemblies which are sealed so as to exclude dust and moisture (see 2.10.7)." It clearly states "for components and subassemblies". Your Pollution 1 argument requires the use of the IP66 enclosure. But is the product/enclosure pairing still considered a 'component' or subassembly'? The way I see it is that the product without the enclosure is the component or subassembly, and that installing the product in the IP66 enclosure make the product a 'top-level'. If for some reason the gasketing on the enclosure fails, or it is not closed properly, the product would not comply. Seems risky to me? (This is my opinion only, not that of my employer). John Juhasz Fiber Options Bohemia, NY -----Original Message----- From: Massey, Doug C. [ mailto:masse...@ems-t.com <mailto:masse...@ems-t.com> ] Sent: Monday, April 02, 2001 11:47 AM To: 'IEEE Forum' Subject: 950 Pollution degree detirmination Hello group - In the -950 series standards, three Pollution Degrees are defined for detirming insulation coordination. For instance, in EN60950 3rd Ed., clause 2.10.1 defines Pollution Degree 1 " for components and subassemblies which are sealed so as to exclude dust and moisture (see 2.10.7)." Clause 2.10.7 gives test requirements for temp cycling, humidity, and electric strength tests, although compliance to the clause is given as "...inspection from the outside, measurement, and, if necessary, by test." I would like to use Pollution Degree 1 when evaluating a product that has a dust and water ingress rating of IP66 per IEC - 60529, Degrees of protection provided by enclosures (IP Code) . The product itself is intended for use in a Pollution Degree 3 environment, but the creepages and clearances inside the unit are subject to Pollution Degree 1, thanks to the protection provided by the enclosure. Is the IEC-60529 report, showing a IP rating of IP66, adequate to satisfy the requirements of 2.10.1 & 2.10.7 for using Pollution Degree 1 when assessing clearance and creepage ? Thanks in advance. Doug Massey Safety Approvals Engineer LXE, Inc. Norcross, GA., USA Ph. (770) 447-4224 x3607 FAX (770) 447-6928 e-mail: masse...@lxe.com Cruise our website at: http:\\www.lxe.com <http:\\www.lxe.com> ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ <http://www.ewh.ieee.org/soc/emcs/pstc/> To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ <http://www.rcic.com/> click on "Virtual Conference Hall,"
