John, I think this 'clarification' is actually confusing.
Fig 8 (61000-4-4:2004) shows 1m between the coupling device (in this case the capacitive clamp) and the EUT, whilst towards the end of section 7.2.1 it is stated that: 'Unless otherwise specified in the product standard or the product family standard, the length of the signal and power lines between the coupling device and the EUT shall be 0.5m +/- 0.05m' This doesn't appear to give much room for movement, certainly not an increase to 1m. In the 1995 version of the standard there was a clause which said 'The length of the signal and power lines between the coupling device and the EUT shall be 1m or less' This has now been replaced (2004) by the 0.5m requirement Mike Hurley From: [email protected] [mailto:[email protected]] On Behalf Of John Woodgate Sent: 04 December 2007 14:59 To: [email protected] Subject: Re: EFT Setup In message <00b701c81c66$4c389e40$6401a8c0@Mike>, dated Thu, 1 Nov 2007, Mike Hurley <[email protected]> writes: >Hi Ted, Grace > >The only requirement on distance between the EFT generator and the >coupling clamp is a recommended maximum of 1m in Fig 6 (no minimum >specified). > >As regards distance between the clamp and the EUT, the standard states >in section 7.2.1 that 'when using the capacitive clamp, the minimum >distance between the coupling plates and all other conductive surfaces, >except the ground reference plane beneath the coupling clamp shall be >0.5m' so I believe the answer to Graces second question is yes. > >In relation to the 0.5m cable length specified, there appears to be a >contradiction in the standard as in Fig 8 for rack mounted equipment it >indicates a 1m cable length. Does anyone know the reason for this? > > I did take this up with IEC and after a while, I received this reply: "The only requirement on distance between the EFT generator and the coupling clamp is a recommended maximum of 1m in Fig 6 (no minimum specified). ***Correct As regards distance between the clamp and the EUT, the standard states in section 7.2.1 that 'when using the capacitive clamp, the minimum distance between the coupling plates and all other conductive surfaces, except the ground reference plane beneath the coupling clamp shall be 0.5m. ***This is a minimum distance which can be more than 0,5 m, e.g. 1 m. In relation to the 0.5m cable length specified, there appears to be a contradiction in the standard as in Fig 8 for rack mounted equipment it indicates a 1m cable length. Does anyone know the reason for this? ***There is no contradiction according to my comment above. Moreover the distance between the coupling clamp and the EUT on the one hand and the length of the cable between the coupling clamp and the EUT on the other hand should not be mixed up. The first one can be 0,5 m but not less while the second one is 1 m. In my opinion there is no contradiction but rephrasing may be necessary as some users are confused. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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 No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.13/1169 - Release Date: 03/12/07 22:56 No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.14/1171 - Release Date: 04/12/07 19:31 - ---------------------------------------------------------------- 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
