Nor should the safety implication be addressed in the EMC report. They are controlled by the safety evaluation itself and subject to re-evaluation as those parts change. I have been to numerous and well qualified test facilities around the country and have yet to find one that is really good at both functions - safety and EMC. They typically have folks well versed in one, and then assume they aren't busy enough and try to get them up to speed on the other with very limited success - might even say poor success in my opinion. I haven't been to all of them so there might exist one or two that truly can keep up with both sides of the problem I just haven't run into any. On top of which this imposes, in practice a serial approach to the evaluations. One wouldn't want to go to the EMC facility until you have full acceptance of the safety aspects just in case they change. The same is true for the EMC stuff so it ends up a serial rather than a parallel process. If during the respective parallel evaluations I do run into a problem that would affect the other - I would have to repeat the test, but given the design reviews and preliminary tests - that is pretty rare, and my schedule is as short as practical. The serial process would needlessly extend that process, in my opinion. Claims that they must be done that way are, in my opinion and experience, mostly done by those that would profit from the extra work they would pick up in the other doing the other half of the job - and again in my opinion and experience do it poorly.
Gary From: Thomas Cokenias [mailto:[email protected]] Sent: Wednesday, March 13, 2013 10:43 AM To: [email protected] Subject: Re: [PSES] Critical component in EMC report Scott Standard practice for EMC test labs is to test what is presented us and if a component needs to be added or changed to make the product EMC compliant we note the make, model and location of what was changed or added. The safety implications of the EMC change is usually not addressed. We will try to use recognized components for fixes in the power supply for instance, but not necessarily - a ceramic disc capacitor of some value may solve an EMC problem but may not be adequate for meeting safety requirements regarding size, form factor, temperature characteristics, etc. The safety implications of the fix are generally left up to the manufacturer. Tom Cokenias T.N. Cokenias Consulting P.O Box 1086 El Granada CA 94018 tel 650 726 1263 fax 650 726 1252 On Mar 13, 2013, at 10:08 AM, Ed Price wrote: Scott, what is a "critical component?" How would I recognize one? Would it be proper for me to tear open a product to look for these devices? Ed Price WB6WSN Chula Vista, CA USA From: Scott Xe [mailto:[email protected]] Sent: Wednesday, March 13, 2013 8:49 AM To: [email protected]<mailto:[email protected]> Subject: [PSES] Critical component in EMC report It is common not to have critical component list in EMC reports issued from 3rd party laboratories. Those information are essential to track if the correct parts to be used in mass production. What is main reason not to have it as a common practice in the field? Thanks and regards, Scott - ---------------------------------------------------------------- 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]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]>
