Just a couple of notes from experience. We once used an open frame power supply without previous certification. It was done as a custom design because we needed AC or 12VDC operation. We found a small company that would do such a design (very interesting transformer by the way...AC primary, 12VDC primary, two secondaries, a bootstrap)
Anyway, we were only interested in CE marking (not UL/CSA) so we simply had the design reviewed and tested with our product. As for continuation, it was a custom part; so we added the compliance requirements to the part specifications. Yes, I know this doesn't give us complete control; but it does put the responsibility on the correct shoulders. We take responsibility for the product; and we did the testing. But it is up to the supply manufacturer to ensure that he uses the parts specified in the test reports. Our company paid for the testing and we shared the test report information with the manufacturer. So the only guarantee is the manufacturer's integrity. The main downfall of this approach was that I became the middle-man between the supply manufacturer and our test lab. One benefit of this approach is that it shortened design time. We didn't have to wait for the supply to be designed and tested; then integrate it into our test sample for a re-test. Everything was tested all at once. Some may say that this isn't as good as a supplier who gets audited by UL or CSA; but I would argue that a supplier's integrity along with hipot/ground bond testing on your finished product are the most important aspects of your compliance program. Even if a manufacturer is audited by UL or CSA...they won't go to bat for you if there is a lawsuit. You're still only left with supplier integrity as your defense. Another point I wanted to bring out we had a product tested to CSA approvals. Inside, we used a power supply that carried a UL listing with "C US" subscript which said that UL tested it to both UL and CSA standards. A copy of the test report wasn't enough for CSA. Since UL did the testing, they wanted construction details. The manufacturer that we wanted to use refused to provide them (I have to agree on this one.) This left a very sour taste in my mouth regarding the whole "C US" dual approval issue. What is the point of UL providing a "C US" lising if CSA treats it as if it means nothing? Anyway, that isn't the issue...I wanted to bring out two points 1. There is occasionally an argument for using a power supply that doesn't have previous approvals. 2. Power supplies with previous approvals still don't guarantee a smooth ride through agency testing...especially when you get caught in the middle of a "posturing" contest between the agencies. If my message doesn't help clear the water; I hope it at least helps you figure out where some of the mud came from :-) Chris Maxwell | Design Engineer - Optical Division email [email protected] | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | > -----Original Message----- > From: Brian O'Connell [SMTP:[email protected]] > Sent: Thursday, September 26, 2002 9:50 AM > To: [email protected] > Subject: RE: subcontracted parts - compliance with EN's > > > CONFLICT OF INTEREST NOTICE: > My employer makes componet power supplies (almost all types). > > I was waiting for someone (Mr Woodgate?) to jump on this... > > I can think of no reason to ever build in a component power supply, that is > connected to mains, or a safety-related TNV source, that does not have an > existing CB report and/or a major agency approval. There is no way that you > can demonstrate control of the construction of a power supply unless the > vendor is subject to FUS audits by the applicable agency(s).> > > A (CE-type) declaration of conformity does not prove anything. > > You do not need construction details for a recognized power supply, your > agency engineer will be the "escrow agent" for the CB report. My complany > routinely provides copies of our CB report to agency engineers. We seldom > provide detailed construction data to a customer, unless it is a custom > power supply. Get a copy of the installation instructions, a copy of the CB > and safety agency certs, and you are done... > > I do not speak for my employer. > > R/S, > Brian > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
