Re: [PSES] breakage of the fuse
The standard 35A or so breakage capacity glass fuses may fulfill your needs in a household situation with relative low prospective short circuit currents. If used on branches with higher currents (say 64A or even more) the prospective short circuit current will be even higher (50 kA) leading to the failure you mentioned. Small glass fuses can be obtained with 1500 A safe breaking capacity. If you need even more you need other type (large in general) of fuses and fuse holder. Not that the wiring diameter in the protected circuit should keep up with that. Regards, Ing. Gert Gremmen, BSc g.grem...@cetest.nl www.cetest.nl Kiotoweg 363 3047 BG Rotterdam T 31(0)104152426 F 31(0)104154953 Before printing, think about the environment. -Oorspronkelijk bericht- Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens Boštjan Glavic Verzonden: Thursday, August 08, 2013 6:21 AM Aan: EMC-PSTC@LISTSERV.IEEE.ORG Onderwerp: RE: [PSES] breakage of the fuse Dear all, Thank you for your comments. The below mentioned construction was rejected. The client needs to use high breaking fuse and not enhanced fuse. The problem is that in every switch mode power supply you can get high short circuit current which is causing non-high breaking fuse to burst (there is a resistance 1ohm even with power supply cord). This happens during fault condition testing in primary circuit right after the fuse (e.g. across the varistor or diode bridge). But test has to be performed on the correct branch circuit and in peak of input voltage. But the problem is that standard does not define precisely how to conduct the abnormal condition (e.g. IEC 60950-1). There are many power supplies on the market with low breaking or enhanced breaking type of fuse and they are approved by different certification bodies. Some power supplies have only TR5 low breaking fuse. That's why I decided to ask you experts for 2nd opinion. UL has a PAG about this issue and does not allow it. However in the past many such construction were acceptable also by UL. Best regards, Boštjan Glavič Head of Laboratory, Laboratory of Electronic Engineering www.siq.si SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678 t +386 (0)1 4778 265, m +386 (0)41 391 283, f +386 (0)1 4778 444 -Original Message- From: Pete Perkins [mailto:peperkin...@cs.com] Sent: Wednesday, August 07, 2013 11:33 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Cc: Boštjan Glavič Subject: RE: [PSES] breakage of the fuse Bostjan commented: During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? - - - - - Bostjan, Such a question can have several answers, among other things it depends upon who the 'you' is. If the 'you' is a party who suffered personal injury or financial damage they probably wouldn't be willing to accept such construction you will hear from them. If the 'you' is a test house or regulator they probably would be looking closely for a way to not accept such construction. If the 'you' is a tinkerer who likes to solve difficult problems they probably would accept such construction be happy that they could fix it and get on with using the product. Perhaps the question you should ask is 'would your mother accept such construction?' or would she be all over you because of what happened. Would the general public know how to clear out the mess in the fuseholder and insert a new fuse to get back in operation? Think about it; not all questions have one simple answer. :) br, Pete Peter E Perkins, PE Principal Product Safety Engineer PO Box 23427 Tigard, ORe 97281-3427 503/452-1201 fone/fax p.perk...@ieee.org - 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://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 emcp...@radiusnorth.net 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
Re: [PSES] breakage of the fuse
-Original Message- From: Boštjan Glavič [mailto:bostjan.gla...@siq.si] Sent: Wednesday, August 07, 2013 21:41 Peter, Fuse is not replaceable. It needs to be sleeved (tubed) and only manufacturer can repair the power supply. Due to the tubing, there is not likely that vaporized metal would affect other parts and decrease safety distances. Boštjan - Don't be too hasty in that tubing assessment, simply because it's there. The pressures involved can be substantial and the sealing ability of the tubing would need to be carefully reviewed, as well as application methodology (work instructions and craftsmanship). After a fuse opens the circuit involved, the tubing needs to be cut open to look for evidence of metal vapor deposition. Assume nothing. During my employ at a well known NRTL, I was responsible for testing glass tube and other fuses, as well as having seen glass tube fuses crack, ferrules become dislodged (even on solder in place fuses), when the interrupting (breaking) capacity was too low for an application in end-product equipment. I'm glad the fuse will be replaced with another, more approriate type. Peter Tarver This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message. - 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
What is the breaking capacity of the fuse? Sounds like it may be a low breaking capacity fuse. If it is you should change it to a high breaking capacity fuse. From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Boštjan Glavic Sent: Tuesday, August 06, 2013 12:46 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: breakage of the fuse Dear safety experts, During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? Best regards, Bostjan SIQ - 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.orgmailto: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://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 emcp...@radiusnorth.netmailto:emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.orgmailto:mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.orgmailto:j.bac...@ieee.org David Heald dhe...@gmail.commailto: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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
Bostjan commented: During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? - - - - - Bostjan, Such a question can have several answers, among other things it depends upon who the 'you' is. If the 'you' is a party who suffered personal injury or financial damage they probably wouldn't be willing to accept such construction you will hear from them. If the 'you' is a test house or regulator they probably would be looking closely for a way to not accept such construction. If the 'you' is a tinkerer who likes to solve difficult problems they probably would accept such construction be happy that they could fix it and get on with using the product. Perhaps the question you should ask is 'would your mother accept such construction?' or would she be all over you because of what happened. Would the general public know how to clear out the mess in the fuseholder and insert a new fuse to get back in operation? Think about it; not all questions have one simple answer. :) br, Pete Peter E Perkins, PE Principal Product Safety Engineer PO Box 23427 Tigard, ORe 97281-3427 503/452-1201 fone/fax p.perk...@ieee.org - 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
When a fuse's interrupting (breaking) capacity is too low for an application and the fuse opening interrupts current in a manner that causes the glass to crack or break, the temperature gradient across the glass and the internal pressure created by the plasma when the fusible element vaporized can and will push some of the vaporized metal out of the confines of the glass and contaminate the surrounding area. Sometimes the deposited metal is not readily visible and even if visible does not always clean up easily or well. The Creepage Distances may be compromised. Depending on the overall design, this can cause increases in touch current (leakage current) and otherwise increase the risk of electric shock with continued product use. Replacement of the fuse can become more frequently necessary due to the contamination allowing unintentional current flow to keep the product operating. If each successive fuse replacement uses the same fuse, more of the same may result. If the product isn't returned for replacement or discarded, the fuse might eventually be replaced with a larger rated fuse with possible further degradation of safety. Peter Tarver This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message. - 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
Dear all, Thank you for your comments. The below mentioned construction was rejected. The client needs to use high breaking fuse and not enhanced fuse. The problem is that in every switch mode power supply you can get high short circuit current which is causing non-high breaking fuse to burst (there is a resistance 1ohm even with power supply cord). This happens during fault condition testing in primary circuit right after the fuse (e.g. across the varistor or diode bridge). But test has to be performed on the correct branch circuit and in peak of input voltage. But the problem is that standard does not define precisely how to conduct the abnormal condition (e.g. IEC 60950-1). There are many power supplies on the market with low breaking or enhanced breaking type of fuse and they are approved by different certification bodies. Some power supplies have only TR5 low breaking fuse. That's why I decided to ask you experts for 2nd opinion. UL has a PAG about this issue and does not allow it. However in the past many such construction were acceptable also by UL. Best regards, Boštjan Glavič Head of Laboratory, Laboratory of Electronic Engineering www.siq.si SIQ Ljubljana, Trzaska c. 2, SI-1000 Ljubljana, Slovenia, VAT ID: SI23509678 t +386 (0)1 4778 265, m +386 (0)41 391 283, f +386 (0)1 4778 444 -Original Message- From: Pete Perkins [mailto:peperkin...@cs.com] Sent: Wednesday, August 07, 2013 11:33 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Cc: Boštjan Glavič Subject: RE: [PSES] breakage of the fuse Bostjan commented: During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? - - - - - Bostjan, Such a question can have several answers, among other things it depends upon who the 'you' is. If the 'you' is a party who suffered personal injury or financial damage they probably wouldn't be willing to accept such construction you will hear from them. If the 'you' is a test house or regulator they probably would be looking closely for a way to not accept such construction. If the 'you' is a tinkerer who likes to solve difficult problems they probably would accept such construction be happy that they could fix it and get on with using the product. Perhaps the question you should ask is 'would your mother accept such construction?' or would she be all over you because of what happened. Would the general public know how to clear out the mess in the fuseholder and insert a new fuse to get back in operation? Think about it; not all questions have one simple answer. :) br, Pete Peter E Perkins, PE Principal Product Safety Engineer PO Box 23427 Tigard, ORe 97281-3427 503/452-1201 fone/fax p.perk...@ieee.org - 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
In message f3471a52242d724da04c8a85ac1ca33a91c8a...@ser-ex01.siq.si, dated Tue, 6 Aug 2013, =?iso-8859-2?Q?Bo=B9tjan_Glavi=E8?= bostjan.gla...@siq.si writes: During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. This indicates that the fuse is being used beyond its safe interrupting current rating. To meet most safety standards, components must be used within their ratings, so your scenario is not allowed. What happens to the glass is irrelevant. How can the fuse be safely replaced? The tubing must be damaged by the explosion (yes, it IS an explosion). -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Why is the stapler always empty just when you want it? 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
No From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Boštjan Glavic Sent: Monday, August 05, 2013 9:46 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: breakage of the fuse Dear safety experts, During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? Best regards, Bostjan SIQ - 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
Yes do the test 3 times to check for repeatable results Sent from my iPhone Peter S. Merguerian pe...@goglobalcompliance.com Go Global Compliance Inc. www.goglobalcompliance.com (408) 931-3303 On Aug 6, 2013, at 8:31 AM, Brian Oconnell oconne...@tamuracorp.com wrote: No From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Boštjan Glavic Sent: Monday, August 05, 2013 9:46 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: breakage of the fuse Dear safety experts, During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? Best regards, Bostjan SIQ - 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://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 emcp...@radiusnorth.net 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] breakage of the fuse
Hello Bostjan: I agree with John Woodgate. The fuse is being used beyond its ratings. It cannot be relied upon to interrupt the fault current. Rich On 8/5/2013 9:46 PM, Boštjan Glavič wrote: Dear safety experts, During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? Best regards, Bostjan SIQ - 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 mailto: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://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 emcp...@radiusnorth.net mailto:emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org mailto:mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org mailto:j.bac...@ieee.org David Heald dhe...@gmail.com mailto: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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
[PSES] breakage of the fuse
Dear safety experts, During the abnormal tests in primary circuit, internal input fuse operates and glass breaks. However, fuse is inside the tubing and broken glass does not spread around. Would you accept such construction? Best regards, Bostjan SIQ - 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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
