Hello Amund,
Generally, if you have chosen to make an enclosure IPX6 for whatever reason, you probably have a robust system of gaskets and enclosure, and truly expect no water inside the enclosure. The fact that you had a little bit of water penetrating an IPX6 enclosure is normally an indication that that robust system of gaskets and enclosure suffered a near-miss failure. At this point, you would either have the mechanical designers make re-adjustments (adjust the torque values of fasteners, bring in the paw latches on doors, use a thicker gasket, etc.), or you would re-test at a less-severe enclosure value such as IPX5, if that is an option. Another concern is whether the water came in to a “wet area”, one equipped with drains that you expect to get wet, or did it penetrate the enclosure in a random manner and get on top of electronic parts that expect to be in a dry location. If it came in randomly, say in the middle of a gasketed-door interface, then you probably want to reject these results, modify and retest. I have in-house capability to test for IPX6 as well as NEMA 4, and I get designers to send me test samples early. This is because, from a probability standpoint, I expect them to fail more times than not the first time through. There is a normal test-mitigate-retest progression that goes on. Water ingress failures tend to be chaotic in nature, and are often difficult to fix. So, early testing allows the designer time to make changes. One last point—the “garden-hose test” that you might have conducted on your sample before subjecting it to the IPX6 test is fine to weed out obvious problems, but it is not in the class of water impact that the IPX6 test delivers at 100 liters per minute through a 12.5 mm diameter nozzle. It is closer to pre-compliance for an IPX5 test of 12.5 liters per minute through a 6.3 mm diameter nozzle. Best regards, Don Gies Senior Product Compliance Engineer Alcatel-Lucent Murray Hill, NJ 07974-0636 USA ________________________________ From: Amund Westin [mailto:[email protected]] Sent: Wednesday, November 18, 2009 11:37 AM To: [email protected] Subject: IP test - pass or fail? We’re doing an IPX6 test (high pressure water jet) according to IEC60529. Some water enter the unit, but drain holes make their job. Only plastic enclose in that area anyway. But, a few drops are discovered on a plastic material switch inside the unit and also some drops on two connection poles on the swicth. We have failed on this test because (according to the test lab) in the long term, creepage currents can cause the two poles to be shorted and thereafter a incorrect function will appear. Is it likely to believe that such creepage currents can occur, when the two poles are placed 10mm from each other and the voltage supply is 3.3VDC? b.r. Amund - 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
