Competent Bodies have differing opinions. I believe if you contacted several, they would not all give the same answer on your ESD question. Clearly, the trend is to test to IEC 801-2:1991 or EN 61000-4-2, which call out the same ESD discharge network. Contact discharge is the preferred method and is performed into metallic surfaces, air discharge should be applied only on non-metallic surfaces. Therefore, I agree with your rationale to perform 4 kV contact only on an all metallic EUT. I have used the following rationale for justification:
Alliant Techsystems, Advanced Technology Applications has taken the stance that ESD should be performed to the more recent IEC 801-2:1991, referenced in the informative annex of EN 50082-1:1992. The 1984 ESD test had repeatability problems with the air discharge test, and with development of transient digitizers with >1 GHz bw, it was found that the discharge network specified in the 1984 spec. did not accurately simulate the ESD waveform. The more recent 801-2:1991 addresses these deficiencies with a 330 W, 150 pF discharge network, and a contact discharge tip. A 4 kV contact discharge is equivalent in severity to an 8 kV air discharge. Doug Frazee EMC Compliance Engineer Alliant Techsystems, Inc. Annapolis, Maryland 21401 USA Tel: (410) 266-1793 FAX: (410) 266-1853 [email protected] >---------- >From: [email protected][SMTP:[email protected]] >Sent: Thursday, February 06, 1997 7:25 PM >To: [email protected]; [email protected] >Subject: ESD requirement for ITE. > > >Hello everyone, > >I have a question in reference to the generic immunity standard EN50082-1. > If I am not mistaken, as of now the "adapted" version is 1992. If this is >so, the document clearly calls out IEC 801-2:1984 as the ESD test procedure. > Here is my question: > >If you are testing an all metal device, and are using the waveform from >IEC801-2:1991, and you are following the soon-to-be-adapted 1991 version (or >using the 1000 series document), then you would simply perform 4 kV contact >discharge and be done with it. However, while I was employed by a >commercial test house, I was informed by a CB that this is not OK, because >you are not meeting the 8 kV requirement as called out by EN50082-1. > >So my question is this - Do I really have to do 8 kV air discharge testing >all of the user accessible conductive parts? Or, should I be doing Contact >discharge to 8 kV? > >It seems to me that I could just ignore the CB and test to the new ESD >procedure. Anyone have any input? >
