Someone please immediately provide feedback if I am not correct, but the answer to the question "In which document do they describe/quantify this parameter?" seems to be NONE. I have never seen this quantified, and have never heard an agency engineer describe the properties of 'conductive pollution', other than the di-electric breakdown level is decreased.
There are some DoD docs where you can use some imagination and deduce some of these parameters (MIL-STD-202, MIL-STD-210, MIL-STD-810) and/or test methods. Perhaps the best approach would be to 'work backwards' from the test materials used to determine the CTI, which is part of the construction data required to establish the requirements for an enclosure. Another idea. Perhaps it is intentional to not quantify. As pollution degree refers to the 'micro-climate', it is dependent on the construction materials in the product. Liquid or solid precipitates that may or may not be conductive will have different effects on the material that it condenses or falls on, depending on the PLC/CTI/IP ratings. luck, Brian From: [email protected] [mailto:[email protected]]On Behalf Of [email protected] Sent: Tuesday, November 13, 2007 3:45 PM To: 'Gary Tornquist' Cc: '[email protected]' Subject: RE: Pollution Degrees Hi Gary: In IEC 60664-1, 2nd edition: 3.1.1: Defines pollution 3.1.3: Defines pollution degree 4.6.2: Degrees of pollution in the micro-environment (describes the 4 degrees) In IEC 60664-1, 1.1, 1.2 editions: 1.3.11: Defines pollution 1.3.13: Defines pollution degree 2.5.1: Degrees of pollution in the micro-environment (describes the 4 degrees) For a very good background treatise, see Klaus Stimper's "The Physical Fundamentals of Low Voltage Insulation Co-ordination," published by VDE. Section 5.1.3 describes micro-environmental categories, the predecessor to pollution degrees. (The English version of this booklet is out of print.) If the 664 degree descriptions are not detailed enough for your use, this booklet may describe the MEC's with the detail that you are looking for. Best regards, Rich From: [email protected] [mailto:[email protected]] On Behalf Of Gary Tornquist Sent: Tuesday, November 13, 2007 11:00 AM To: [email protected] Subject: Pollution Degrees Compliance comrades - We've dug through IEC 60664-1. Unfortunately, we did not find what I was looking for. I need your help once again. I am looking for an official expose on what the IEC precisely means by 'Pollution Degree'. In which document do they describe/quantify this parameter? I understand that it generally means 'conductive dust and/or moisture' and that it is used to establish categories of creepage/clearance distances. Well, what the heck is 'conductive dust' and how do they quantify the moisture levels? - our Reliability team is trying to quantify moisture/dust exposure and acceleration factors. Thanks for your help! Sincerely, Gary Tornquist Director of Product Safety Microsoft Corp. 425-705-6099 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
