Hello Fred, I recently assessed six EMC labs in Taiwan and all of them are in full compliance with applicable IEC, CISPR, FCC and EN specifications as well as with ISO Guide 25 General requirements for the competence of calibration and testing laboratories. All of them provide highly professional, high quality and repeatable EMC testing with test equipment daily verified and calibrated every SIX months, practice not very often in U.S.
Answers to your questions: 1. Proficiency testing is required by different laboratory accreditation programs. Large companies with few EMC test facilities usually develop in-house programs to better handle site correlation. 2. EN and IEC ESD specifications define ground reference plane, horizontal and vertical coupling planes, position and connection of UUT and ESD generator. Different earthing methods of the test setup should not affect results of ESD test immunity. Without knowing other test details, I guess that your system (non)complies with the specification with a slim margin. Mirko Matejic The Foxboro Company ---------- From: Fred Waechter To: emc-pstc discussion group Subject: IEC801-2 List-Post: [email protected] Date: Monday, December 09, 1996 12:23PM This is in relation to testing a Class II, 2 wire system to the European IEC801-2 electrostatic discharge requirements. The system is used in an environment that may have no earth ground, or earth may be tied back at the substation, or earth may be tied at multiple points along the AC neutral, or an earth ground rod me be available at the users end installation. On application of an ESD pulse to this system, the energy in the ESD pulse will try to find the shortest path to earth ground. 1. Is there a preferred test method to insure conformity of testing between test laboratories, and also the users end installation as their methods of earthing may certainly differ? 2. Would different methods of earthing result in differing results due to differing amounts of system discharge before the next ESD pulse is applied to the system? These questions were prompted by results obtained at two different test laboratories. The systems passed when tested at an independent test lab. in Taiwan. The same units failed when tested by a lab. in the U.S. Thanks for your help.
