Adam
I’m not sure that reading and trying to understand the standards themselves in detail is the best first step in understanding the design issues because most standards are written mainly for test and certification organisations, rather than design engineers – and the latter often have a lot of problems in interpreting the requirements in the context of the equipment on which they working. The problems surface for many reasons: - The structure of some standards, which may seem somewhat random – why is this here and that there (etc.)? That has developed over many years, and is reasonably consistent across many IEC/EN standards, but can be confusing to newcomers; - The multiple options for doing “something” with no indication of which would be best (in fact, one of the guiding principles of standards preparation is not to do that, but to give the designer as much freedom as possible to meet the “essential” requirements of that particular section of the standard); - The apparent (and sometimes real) conflicts in requirements between apparently similar standards, and even, occasionally, within the same standard; - The often abysmal level of comprehensibility of many of the sections in some standards where the requirements have grown and been tweaked over the years by various committees – often, one paragraph will contain multiple requirements and cross-references, which you then have to carefully dissect before you can determine what parts do/do not apply to your product. Therefore, I would suggest that you need to start reasonably “simply” / cheaply, and so: - Find out what standards apply to your product (presumably, from what you say, that would include 60950-1 or the new 62368-1 – which is much better written, IMHO, although the scope and structure are somewhat different – which is replacing it), but it does not really matter all that much if all you can get your hands on is an older version of a document (there are “sources”) because the basic requirements haven’t actually changed that much over the last 20-30 yrs (although some of the detailed requirements have, but generally just to clarify previously unclear wording)! - Familiarise yourself with the overall structure of the document (you can get first few pages and the index to the standard from the free synopsis which can be downloaded from the IECEE website in Geneva!) Identify the parts are likely to apply to the product – basically, that’s those for the enclosure, means of connection to the mains supply, and the circuits to which those connect within the unit, PSUs, access to Hazardous Live parts, output connections, and – significantly – the requirements for the components and materials within the enclosure (notably creepage/clearance distances and flammability) Do this by taking a typical product, opening it up and then working out roughly what requirements are liable to apply to what parts. - Delve into those, one-by-one, in the specific context of the overall design and the detailed component requirements - which you can do by some basic searching on the web – but don’t try to go too deep before you begin to understand how all the requirements begin to “fit together” as a whole. Once you have begun to understand the above, sit back and decide what you think you do understand, and what you don’t – and then ask questions here on this forum as there are many people with the relevant knowledge who are very willing to assist. Just like many other learning processes it will take some time, and it’s an ongoing one – that’s why many of us here on this forum are still learning towards the ends of our careers in the industry! J Regards John Allen W.London, UK From: Adam Dixon [mailto:lanterna.viri...@gmail.com] Sent: 17 March 2015 00:18 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Safety standards versus safety engineering For the design engineer who wants to learn more about safety regarding both product design (systems using 85-264VAC sources; mostly digital logic but including an Ethernet physical layer interface) and production test, but is on a very tight budget, are there recommended references? Soft and/or hardcopy are fine. I have searched the archives using a variety of terms to locate recommended references but didn't locate any lists. I've read the discussions about lowest cost sources for standards. IEC 60950-1:2013 is 707 Euros from what I see on the Estonian site. The UL version is $493 for starters. Purchasing any number of standards certainly is a moderate to significant investment for the individual. I checked out the HBSE per Rich's post about how it came to be, but don't have $1050 for the two day workshop at this time either. There look to be a handful of texts on Amazon. Electrical Safety Handbook, 4th edition looks like the most appropriate title -- any benefit with something from Amazon or other publishing house/distributor compared to the actual standards? If I've missed pertinent discussions in the archives or if you would consider sharing a recommended reading/standards list, I would appreciate any guidance/feedback. Kind regards, Adam Dixon adam.di...@ieee.org On Wed, Mar 4, 2015 at 9:30 PM, Richard Nute <ri...@ieee.org> wrote: Many years ago, a group of R&D engineers came to me and said: "We want to learn about product safety, but we don't want to read the standards." The result was the HBSE course. If the product safety engineer does his job, there will be no test failures. Best regards, Rich > -----Original Message----- > From: Nyffenegger, Dave > [mailto:dave.nyffeneg...@bhemail.com] > Sent: Wednesday, March 04, 2015 12:41 PM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: Re: [PSES] Estonian Standards MultiUser > License > > Same message I've been communicating here internally > as well. Management certainly supports and expects to > have it right the first time but educating on what needs to > happen and by who to accomplish that seems to be a > recurring theme. > > -Dave > > -----Original Message----- > From: John Woodgate > [mailto:j...@jmwa.demon.co.uk] > Sent: Wednesday, March 04, 2015 2:48 PM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: Re: [PSES] Estonian Standards MultiUser > License > > In message > <BLUPR0701MB8208F224B64620D128B43E9E31E0@ > BLUPR0701MB820.namprd07.prod.out > look.com>, dated Wed, 4 Mar 2015, Brian Ceresney > <bceres...@delta-q.com> > writes: > > > As a matter of fact, it is very difficult to get our > engineers to > >take an interest in reading and understanding the > standards at all, > > That is BAD. I forestalled it with my group by > explaining that while the safety and EMC experts did the > tests, THEY were responsible for THEIR designs > conforming. They were, of course, free to ask advice and > assistance from the experts, but when the designs came to > be tested, I said that I did not expected them to fail. > > Senior managers found this arrangement seriously > intellectually challenging. Of course, what it does is > eliminate almost all friction between the designers and > the 'testers' - they are all in the same boat, which is as it > should be. > -- > OOO - Own Opinions Only. With best wishes. See > www.jmwa.demon.co.uk When I turn my back on the > sun, it's to look for a rainbow John Woodgate, J M > Woodgate and Associates, Rayleigh, Essex UK > - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
