Derek, When we test, we generally start off with the emissions tests first, then proceed to the immunity tests with CI first, then EFT and Surge last, since those tests are the most likely to be destructive. Since we cut the cable for CI, we simply add on enough cable for the other tests, mainly to meet the 0.5m requirement for EFT. When testing 55014 products, we almost always cut the cable to add the necessary 5m for the disturbance power test. I have not seen a power plug yet that will fit through the absorber clamp. :-) Bob R.
--- On Tue, 2/8/11, Derek Walton <[email protected]> wrote: From: Derek Walton <[email protected]> Subject: Re: EUT power cord length To: [email protected], [email protected] Date: Tuesday, February 8, 2011, 3:21 PM Thanks to the folks that have replied so far. Here's my dilemma, the EFT standard says: If the manufacturer provides a non-detachable supply cable more than 0,5 m ± 0,05 m long with the equipment, the excess length of this cable shall be folded to avoid a flat coil and situated at a distance of 0,1 m above the ground reference plane. Surge is similar. However, CI is not. On all cables to be tested, coupling and decoupling devices shall be inserted (see 7.1.2). The coupling and decoupling devices shall be placed on the ground reference plane, making direct contact with it at a distance of 0,1 m to 0,3 m from the EUT. The cables between the coupling and decoupling devices and the EUT shall be as short as possible and shall not be bundled or wrapped. Their height above the ground reference plane shall be between 30 mm and 50 mm. So what this is telling me, I believe, is that the Surge and EFT must be done first with the manufacturer supplied cable ( Or the connection remade ) and the cable bundled non-inductively. For CI, regardless of supplied cable length, the cable must be cut to the minimum practical length. I hear what is said about robust EUT's, but the requirement is to follow the standard.... I think I have my answer... Thanks everyone, Derek Walton L F Research -----Original Message----- From: Spencer, David H <[email protected]> To: Derek Walton <[email protected]>; [email protected] Sent: Tue, Feb 8, 2011 1:39 pm Subject: RE: EUT power cord length The obvious question: does it make a difference with respect to test results between .5M and 5M? If the EUT is sufficiently robust, it may not make a difference. If you determine a worse case I would go with that. Of course, hacking bits off at a time may not make the customer happy. You could just directly inject into the in-let terminals of the EUT (I'm sure that's coming in a future revision of IEC 61000-4-4). ;) Regards, David Spencer EH&S EMC Engineer Xerox Corp -----Original Message----- From: [email protected] <http://us.mc1 .mail.yahoo.com/mc/[email protected]> on behalf of Derek Walton Sent: Tue 2/8/2011 2:22 PM To: [email protected] <http://us.mc11. ail.yahoo.com/mc/[email protected]> Subject: EUT power cord length Hi Group, I have a question concerning what to do with an EUT's non detaching power cord for EFT, Surge and CI. Lets say the EUT comes with 5 metres of cable, what would I do with this cable between the coupling networks and the EUT? Do I cut to a shorter length, bundle etc? I'm stressing non detaching power cord.... Opinions welcome. Thanks, Derek Walton - ---------------------------------------------------------------- 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] <http://us.mc11.mai .yahoo.com/mc/[email protected]> > All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. 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