Re: 60950 SFC - Rathole warning
I read in !emc-pstc that Gregg Kervill gkerv...@pgtv.net wrote (in 000401c1bc76$fb459a10$7e00a8c0@MENHADEN) about '60950 SFC - Rathole warning', on Sat, 23 Feb 2002: Please do not take emphasis AWAY from the point that I was trying to make: We are required (by the standards, general morality, legal liability, etc) to ensure that products will remain 'safe' under worst case conditions. Hence we spend much soul-searching to evaluate and to test under 'worst-case' conditions. I considered that your point needed *clarification*. I was certainly not de-emphasizing such an apparently provocative statement. The example was merely to show one area where designers get it wrong - and there are too many to list - hence I emphasis the principle of responsibility - and worst-case... Designers get it wrong? The use of low-current fuses (although not 1 A or 2A in the BS1363 plug; they go in BS546 plugs and clock connectors) is permitted by BS1363 and BS7671. In answer to your specific question: typically a manufacturer (wrongly) selects a plug with a 13A marking and fits a 1,2,3,5,7Amp fuse. When the fuse blows the user then replaces it with a 13A fuse. As per the generic 13A marking on the plug. I have seen this done by many engineers in many companies - but it is only ONE of the common errors. You might have a claim that this is 'foreseeable misuse', which is a much wider subject that the electrical safety committees now have to take into account, for Europe anyway. In some cases, this will lead to new restrictions on design. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
RE: 60950 SFC
Brian, The fault tests must be conducted with branch circuit fuses or breakers anticipated at the supply during installation. So, for a 30 A unit connected to a 30 A central office noninal -48/60 V supply, you should be conducting test with 1.5 x 30 A - 45 A or next larger fuse available in the country of destimation. For a 12-16 A mains operated unit in the US, the branch circuit fuse you would be conducting fault testing is 20 A. For same unit rated up to 12 A, the branch circuit fuse is 15 A. For power suipply tests, I advise my clientele to test at the highest branch circuit fuse they believe their power supplies might be installed. It is of no use to the end-product manufacturer of CO equipment rated 30 A to chose a power supply that has been tested by fault tests at 15A or 20 A. There are many things that are not written in the standards because of the various local codes in the various countries. The UL60950 standard for example, refers you to the National Electrical Code (NEC) and this is where you find information regarding branch circuit fuses at the installation. -Original Message- From: Brian O'Connell To: emc-p...@ieee.org Sent: 2/22/02 9:28 PM Subject: 60950 SFC Good People of PSTC My notes from an agency (60950) seminar state that fault conditions shall be done with 16A installation fuses. I cannot find any clause in EN60950:2000 or UL60950, 3d Ed with this requirement. Is this test requirement in one the stds listed in 60950, or am I blind? R/S, Brian O'Connell Taiyo Yuden (USA), Inc. --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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 --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
RE: 60950 SFC - Rathole warning
Please do not take emphasis AWAY from the point that I was trying to make: We are required (by the standards, general morality, legal liability, etc) to ensure that products will remain 'safe' under worst case conditions. Hence we spend much soul-searching to evaluate and to test under 'worst-case' conditions. The example was merely to show one area where designers get it wrong - and there are too many to list - hence I emphasis the principle of responsibility - and worst-case... In answer to your specific question: typically a manufacturer (wrongly) selects a plug with a 13A marking and fits a 1,2,3,5,7Amp fuse. When the fuse blows the user then replaces it with a 13A fuse. As per the generic 13A marking on the plug. I have seen this done by many engineers in many companies - but it is only ONE of the common errors. Best regards Gregg PLEASE NOTE: We are currently experiencing serious problems with our service provider PLEASE reply only to gr...@test4safety.com mailto:gr...@test4safety.com and ignore any reference to pgtv.net, Thank you. --Original Message- -From: owner-emc-p...@majordomo.ieee.org -[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Woodgate -Sent: Saturday, February 23, 2002 1:19 AM -To: emc-p...@majordomo.ieee.org -Subject: Re: 60950 SFC - - - -I read in !emc-pstc that Gregg Kervill gkerv...@pgtv.net wrote (in -008b01c1bbf5$c76fa950$7e00a8c0@MENHADEN) about '60950 SFC', -on Fri, 22 -Feb 2002: -In the UK domestic plugs can be fitted with fuzes between 1A -and 13A - some -manufacturers supply plugs with a 13A marking AND a 1A fuze. -PLEASE check -that you do not use this configuration - these are potential -fire hazards -waiting to happen. - -Please explain how an approved plug fitted with an approved fuse can be -a fire hazard. --- -Regards, John Woodgate, OOO - Own Opinions Only. -http://www.jmwa.demon.co.uk -Interested in professional sound -reinforcement and distribution? Then go to -http://www.isce.org.uk -PLEASE do NOT copy news posts to me by E-MAIL! - -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: - majord...@ieee.org -with the single line: - unsubscribe emc-pstc - -For help, send mail to the list administrators: - Ron Pickard: emc-p...@hypercom.com - Dave Heald: davehe...@mediaone.net - -For policy questions, send mail to: - Richard Nute: ri...@ieee.org - Jim Bacher: j.bac...@ieee.org - -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 --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
Re: 60950 SFC
I read in !emc-pstc that Gregg Kervill gkerv...@pgtv.net wrote (in 008b01c1bbf5$c76fa950$7e00a8c0@MENHADEN) about '60950 SFC', on Fri, 22 Feb 2002: In the UK domestic plugs can be fitted with fuzes between 1A and 13A - some manufacturers supply plugs with a 13A marking AND a 1A fuze. PLEASE check that you do not use this configuration - these are potential fire hazards waiting to happen. Please explain how an approved plug fitted with an approved fuse can be a fire hazard. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
RE: 60950 SFC
We are required (by the standards, general morality, legal liability, etc) to ensure that products will remain 'safe' under worst case conditions. Hence we spend much soul-searching to evaluate and to test under 'worst-case' conditions. Fuzing in most countries is generally via a 16 A CB or fuze - hence this is used for testing. It is pretty hopeless if the power cord ignites BEFORE the fuze blows - so check out worst case (high, and low voltage) and worst place for short-circuits to maximuze the current - AND to maximize the let-through energy. In the UK domestic plugs can be fitted with fuzes between 1A and 13A - some manufacturers supply plugs with a 13A marking AND a 1A fuze. PLEASE check that you do not use this configuration - these are potential fire hazards waiting to happen. Best regards Gregg PLEASE NOTE: We are currently experiencing serious problems with our service provider PLEASE reply only to gr...@test4safety.com mailto:gr...@test4safety.com and ignore any reference to pgtv.net, Thank you. --Original Message- -From: owner-emc-p...@majordomo.ieee.org -[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Brian O'Connell -Sent: Friday, February 22, 2002 2:29 PM -To: emc-p...@ieee.org -Subject: 60950 SFC - - - -Good People of PSTC - -My notes from an agency (60950) seminar state that fault -conditions shall be -done with 16A installation fuses. I cannot find any clause in -EN60950:2000 -or UL60950, 3d Ed with this requirement. - -Is this test requirement in one the stds listed in 60950, or -am I blind? - -R/S, -Brian O'Connell -Taiyo Yuden (USA), Inc. - - -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: - majord...@ieee.org -with the single line: - unsubscribe emc-pstc - -For help, send mail to the list administrators: - Ron Pickard: emc-p...@hypercom.com - Dave Heald: davehe...@mediaone.net - -For policy questions, send mail to: - Richard Nute: ri...@ieee.org - Jim Bacher: j.bac...@ieee.org - -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 - --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
Re: 60950 SFC
I read in !emc-pstc that Brian O'Connell boconn...@t-yuden.com wrote (in f7e9180f6f7f5840858d3db815e4f7ad1f2...@cms21.t-yuden.com) about '60950 SFC', on Fri, 22 Feb 2002: My notes from an agency (60950) seminar state that fault conditions shall be done with 16A installation fuses. I cannot find any clause in EN60950:2000 or UL60950, 3d Ed with this requirement. Is this test requirement in one the stds listed in 60950, or am I blind? It is certainly inappropriate for UK. We have fused plugtops, 3 A, 5A, 10 A and 13 A, and ring circuits fused at 30 A or with MCBs at 32 A. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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
