Your understanding is correct. It doesn't matter whether the probe reaches the stop before hitting anything. If the probe tip enters the enclosure, the enclosure fails the test.
IEC 529 IP ratings, and NEMA enclosure ratings, are intended determine the level of protection from environmental contamination. The pass/fail criteria for IP2X, 3X and 4X are whether the probe can enter any distance into the enclosure. The test is to determine is environmental contaminants can enter the enclosure, get into the electronics or mechanics and cause the product to fail. It is not necessarily related to human safety. For example, if the equipment has a rating of IP32, no object greater than 2.5 mm can enter the enclosure. It doesn't matter if the electronics are two meters from a grill with 3 mm holes. That would still fail the IP32 requirement. Contaminants between 2.5 mm and 3 mm could enter the enclosure and work their way to the sensitive parts, causing a failure. As a side note, even I get a little careless with the nomenclature. There is a NEMA enclosure rating of 4X which roughly correlates to an IEC 529 rating of IP66 - IP68. There is a rough correlation between NEMA/UL enclosure ratings and the IEC classification, but it is not exact. The test criteria are different. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC, MGE or Schneider Electric. The speaker does not represent APC's, MGE's or Schneider Electric's official position on any matter. "Jim Eichner" <Jim.eichner@Xant rex.com> To Sent by: <emc-p...@ieee.org> emc-p...@ieee.org cc Subject 03/20/2007 07:07 IP testing per EN60529 PM This has to do with the IP 3X, and 4X ratings and tests. The testing is by way of 2.5mm rod or 1.0mm wire probes, which seems quite straight forward at first. But the probes are not meant to be used the way I'm used to. It's not about whether they can touch anything, it's about whether they can enter at all. This is pretty clear in the text and tables giving pass pass/fail criteria, and is made really obvious if you read the note under 13.3. That note says that for IP3X and 4X the requirements are meant to prevent spherical objects of 2.5mm or 1.0mm diameter that are capable of motion from entering the enclosure. So basically an "indirect or tortuous entry path" doesn't do the job and you have to limit the size of an opening somewhere along the path to less than the diameter of the probe. It's easy to get misled on that point, for a variety of reasons: - the probes have a defined length and a "stop", neither of which comes into play with the "shall not enter" criteria, but their presence suggest the more typical "ok to enter but not to touch hazardous parts" criteria - some of the examples in Annex A can easily be misinterpreted - safety compliance people are used to criteria that allows the probe to enter but not touch things - the standard touches on pass/fail in several places and the additional letters and first numeral have requirements that overlap but are different I have seen products on the market and results from certification bodies that make it clear this is being misinterpreted. People are assuming it's ok for the probe to enter as long as adequate clearance is maintained to live parts, whirling blades, etc, when in fact it is not acceptable for the IP3X and 4X probes to enter the enclosure. So given what I am seeing as widespread mis-interpretation my question is, am I wrong? Are the labs and other products on the market right, and I'm misinterpreting the requirements? Thanks, Jim Eichner, P.Eng. Manager - Compliance Engineering Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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