RE: Rack System Safety (UL1950/EN 60950) Questions
Richard, Adding Approved disks, tapes and similar devices and adding model designation usually involves paperwork. However, adding/changing Approved , datacom and other similar equipment usually requires a repeat of some of the tests, including but not limited to Input, Leakage and Capacitance Discharge Tests. Regards, On Wednesday, March 10, 1999 5:00 AM, WOODS, RICHARD [SMTP:wo...@sensormatic.com] wrote: As I think about this situation, there is a way of obtaining UL Listing on the rack and have other certification marks on the internal equipment. Have UL List just the rack without the equipment. Now you can mix and match the internal certified equipment as you see fit keeping in mind not to exceed the cooling and electrical capacity of the rack. This is what we use to do a decade ago at a mini-computer company. We would configure systems from Listed racks, cpus, disks, tapes, etc. RRR. So after we obtained the UL listed for rack (model ABC-001), then we configure, add recognized disks, recognized tapes ...etc. etc.. now it become new model (DEF-001). Do we have to submit this new model for certification again ???. Now to Jim's point. There is no law that requires one agency to accept the certification marks of another agency. For example, UL will not accept ETL marks on components and both are NRTLS. The only way one agency will accept the marks of another is if there is an agreement between them. The CB scheme is one good example. CSA and UL have an agreement to accept each others test data I believe, but I don't believe that they will accept each others marks. RRR. They don't accept each others mark, but would they review and accept test data??? Tac Pham HC Power -- From: Jim Eichner [SMTP:jeich...@statpower.com] Sent: Tuesday, March 09, 1999 3:23 PM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Rack System Safety (UL1950/EN 60950) Questions
That's what I love about this mailing list. I learn something new most every day. Thanks Tania! -- From: Grant, Tania (Tania) [SMTP:tgr...@lucent.com] Sent: Wednesday, March 10, 1999 4:27 PM To: 'EMC-PSTC - forum'; 'WOODS, RICHARD' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Richard, Regarding your last statement I don't believe that they [CSA UL] will accept each others marks. Certain UL and CSA component standards have been harmonized and, I believe, this effort is continuing. If you look at Appendix P.2 [be sure it is P.2 and not P.1] of UL 1950, 3rd edition, you will find a matrix of UL and CSA component standards where meeting one or the other is considered acceptable for meeting the requirements of UL1950, 3rd edition. Additionally, if you are working with an astute UL engineer, very often they will inform you of additional components that fall under that category but have not yet been published in this Appendix. Tania Grant, Lucent Technologies, Octel Messaging Division tgr...@lucent.com -- From: WOODS, RICHARD[SMTP:wo...@sensormatic.com] Sent: Wednesday, March 10, 1999 5:00 AM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions As I think about this situation, there is a way of obtaining UL Listing on the rack and have other certification marks on the internal equipment. Have UL List just the rack without the equipment. Now you can mix and match the internal certified equipment as you see fit keeping in mind not to exceed the cooling and electrical capacity of the rack. This is what we use to do a decade ago at a mini-computer company. We would configure systems from Listed racks, cpus, disks, tapes, etc. Now to Jim's point. There is no law that requires one agency to accept the certification marks of another agency. For example, UL will not accept ETL marks on components and both are NRTLS. The only way one agency will accept the marks of another is if there is an agreement between them. The CB scheme is one good example. CSA and UL have an agreement to accept each others test data I believe, but I don't believe that they will accept each others marks. -- From: Jim Eichner [SMTP:jeich...@statpower.com] Sent: Tuesday, March 09, 1999 3:23 PM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] Sent: Tuesday, March 09, 1999 11:15 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: RE: Rack System Safety (UL1950/EN 60950) Questions 1.Peter, equipment with the standard NEMA plug is considered to be Class A.. 2.Equipment using the heavy duty Industrial plugs complying with IEC are considered to be Class B. I have never seen those used inside rack mounted equipment. 3.If the power supply is UL Listed, then temperature measurements are not required. However, most power supplies are categorized as Recognized and are therefore incomplete in construction - that is, they cannot pass the safety requirements for a stand alone power supply. Temperature measurements will be required. 4.Stability is performed in a worst case situation, but reason is also taken
RE: Rack System Safety (UL1950/EN 60950) Questions
Richard, Regarding your last statement I don't believe that they [CSA UL] will accept each others marks. Certain UL and CSA component standards have been harmonized and, I believe, this effort is continuing. If you look at Appendix P.2 [be sure it is P.2 and not P.1] of UL 1950, 3rd edition, you will find a matrix of UL and CSA component standards where meeting one or the other is considered acceptable for meeting the requirements of UL1950, 3rd edition. Additionally, if you are working with an astute UL engineer, very often they will inform you of additional components that fall under that category but have not yet been published in this Appendix. Tania Grant, Lucent Technologies, Octel Messaging Division tgr...@lucent.com -- From: WOODS, RICHARD[SMTP:wo...@sensormatic.com] Sent: Wednesday, March 10, 1999 5:00 AM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions As I think about this situation, there is a way of obtaining UL Listing on the rack and have other certification marks on the internal equipment. Have UL List just the rack without the equipment. Now you can mix and match the internal certified equipment as you see fit keeping in mind not to exceed the cooling and electrical capacity of the rack. This is what we use to do a decade ago at a mini-computer company. We would configure systems from Listed racks, cpus, disks, tapes, etc. Now to Jim's point. There is no law that requires one agency to accept the certification marks of another agency. For example, UL will not accept ETL marks on components and both are NRTLS. The only way one agency will accept the marks of another is if there is an agreement between them. The CB scheme is one good example. CSA and UL have an agreement to accept each others test data I believe, but I don't believe that they will accept each others marks. -- From: Jim Eichner [SMTP:jeich...@statpower.com] Sent: Tuesday, March 09, 1999 3:23 PM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] Sent: Tuesday, March 09, 1999 11:15 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: RE: Rack System Safety (UL1950/EN 60950) Questions 1.Peter, equipment with the standard NEMA plug is considered to be Class A.. 2.Equipment using the heavy duty Industrial plugs complying with IEC are considered to be Class B. I have never seen those used inside rack mounted equipment. 3.If the power supply is UL Listed, then temperature measurements are not required. However, most power supplies are categorized as Recognized and are therefore incomplete in construction - that is, they cannot pass the safety requirements for a stand alone power supply. Temperature measurements will be required. 4.Stability is performed in a worst case situation, but reason is also taken into account. Most likely, you will determine that it is possible and reasonable to assume that more than one assembly can be extending at the same time. 5.UL requires that all internal equipment be UL Listed or Recognized. --- From: pe...@itl.co.il [SMTP:pe...@itl.co.il] Sent: Tuesday, March 09, 1999 11:26 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: Rack System Safety (UL1950/EN 60950) Questions Dear All, I would like to know some of your professional advice on some issues reagrding rack systems to be evaluated to UL1950/EN 60 950. 1. For the North America, does a NEMA 125 V, 20 A plug meet the pluggable B definition? 2. What are some plug configurations which will meet the pluggable B
RE: Rack System Safety (UL1950/EN 60950) Questions
On Wednesday, March 10, 1999 5:00 AM, WOODS, RICHARD [SMTP:wo...@sensormatic.com] wrote: As I think about this situation, there is a way of obtaining UL Listing on the rack and have other certification marks on the internal equipment. Have UL List just the rack without the equipment. Now you can mix and match the internal certified equipment as you see fit keeping in mind not to exceed the cooling and electrical capacity of the rack. This is what we use to do a decade ago at a mini-computer company. We would configure systems from Listed racks, cpus, disks, tapes, etc. RRR. So after we obtained the UL listed for rack (model ABC-001), then we configure, add recognized disks, recognized tapes ...etc. etc.. now it become new model (DEF-001). Do we have to submit this new model for certification again ???. Now to Jim's point. There is no law that requires one agency to accept the certification marks of another agency. For example, UL will not accept ETL marks on components and both are NRTLS. The only way one agency will accept the marks of another is if there is an agreement between them. The CB scheme is one good example. CSA and UL have an agreement to accept each others test data I believe, but I don't believe that they will accept each others marks. RRR. They don't accept each others mark, but would they review and accept test data??? Tac Pham HC Power -- From: Jim Eichner [SMTP:jeich...@statpower.com] Sent: Tuesday, March 09, 1999 3:23 PM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Rack System Safety (UL1950/EN 60950) Questions
Hello from San Diego: I said: 1. For the North America, does a NEMA 125 V, 20 A plug meet the pluggable B definition? No. The objective of the Pluggable Type B connection is that of a reliable, non-defeatable earth connection. The NEMA 20 A plug uses the same earthing connection as the NEMA 15 A plug. The 15 A plug is notorious for having the earthing connection destroyed or removed in use. A colleague has pointed out that the NEMA 20 A plug is indeed accepted by some North American certification houses as meeting the Pluggable Type B definition. The thinking is twofold: 1) the 20 A receptacle is ALWAYS a grounding type, and 2) the 20 A plug is not subject to the same abuse as the 15 A plug. Best regards, Rich - Richard Nute Product Safety Engineer Hewlett-Packard Company Product Regulations Group AiO Division Tel : +1 619 655 3329 16399 West Bernardo Drive FAX : +1 619 655 4979 San Diego, California 92127 e-mail: ri...@sdd.hp.com - - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Rack System Safety (UL1950/EN 60950) Questions
Peter, Some experiences I have had in past lives follow each of your questions. My responses are brief due to lack of time. I hope this helps. Anyone else, please feel free to comment. Best regards, Ron Pickard ron_pick...@hypercom.com __ Reply Separator _ Subject: Rack System Safety (UL1950/EN 60950) Questions Author: pe...@itl.co.il (Peter Merguerian) at INTERNET List-Post: emc-pstc@listserv.ieee.org Date:3/9/99 6:26 PM Dear All, I would like to know some of your professional advice on some issues reagrding rack systems to be evaluated to UL1950/EN 60 950. 1. For the North America, does a NEMA 125 V, 20 A plug meet the pluggable B definition? R. I must say no. A pluggable type B plug is of the industrial grade (e.g., NEMA twist lock, IEC309, etc.). Anyone correct me if I'm off base here, but an industrial plug (type B) is not normally found in a residential or light commercial (office) environment. 2. What are some plug configurations which will meet the pluggable B equipment requirements for North America and Europe? R. See above. 3. Does anyone have experience with UL and/or CSA and/or TUV when testing a unit employing a Recognized/Certified/Approved computer type totally enclosed power supply? I am interested to know if temperatures should be monitored within such a power supply. So far, I have been asked to thermocouple various points within the power supply and as you all know, it could get very crowded in there. I am interested to know if someone out there knows if such a waiver exists for totally enclosed Approved power supplies. R. Its a pain, I know, but I see no way for you to avoid having to theromcouple points in the power supply as part of your system safety tests. How else are you to verify that the power supply is still within the temperature limits required by the safety standard of your product. 4. When conducting stability tests for rack systems, should all the serviceable card cages be extended out or is it enough to do it one at a time. R. 4.1.1 of UL1950 deals with the subject of stability. If the rack system does become unstable with more than 1 cage extended, then a stabilizing means must be employed or a warning must be conspicuously placed to prevent that. 5. For a CSA NRTLC unit employed in the rack system, does anyone know if the CSA NRTLC Mark is automatically accepted by UL or does UL require that the unit must be re-investigated and placed under their Follow-Up Program? R. I have no experience with this, but UL will likely need detailed information in the form of the equipment's CSA certification report to include test data. After all, if UL allows you to put their mark on your product, I would think that they should want make sure all is ok first. I would suggest that you contact your friendly UL engineer for more details. 6. Has the US Robotics Listed Sporster card modem been evaluated to UL1950 Third Edition? R. I have no idea. I would suggest contacting US Robotics and/or look into UL's Recognized Component Directory or yellow book. 7. Can I List/Certify a rack system to UL1950 Third Edition if the units within it have been Listed/Certified to UL1950 First and/or Second Editions? I do not think so, but am interested to hear your opinions. R. In my experience, I would have to say no. UL1950 1st/2nd Editions are significantly different from the 3rd Edition and even the 3/1/98 revision made significant changes to the 3rd Edition. Doing what you suggest may be mixing apples and oranges. UL should be able to tell you what they need. BTW, see page 11 of UL1950 3rd Edition for effectivity dates. 8. How is a CB test report done for a rack system which consists of previously Listed/Certified/Approved units? Does the CB scheme Recognize the Approvals of the various test agencies (UL/CSA/TUV)? R. In my experience, it's most important that the individual components/sub-systems meet the requirements that would be acceptable to the applicable standard of your product as it relates to the CB Scheme. This can be done as a collection of documents from reputable authorities* such as licenses, approval certificates, test reports, etc., each of which connect the respective components/sub-systems to the requirements. These documents should then be made a part of the greater CB test report. * CB Scheme member NCBs preferred. Thanks in advance. PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes).
RE: Rack System Safety (UL1950/EN 60950) Questions
Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] Sent: Tuesday, March 09, 1999 11:15 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: RE: Rack System Safety (UL1950/EN 60950) Questions 1.Peter, equipment with the standard NEMA plug is considered to be Class A.. 2.Equipment using the heavy duty Industrial plugs complying with IEC are considered to be Class B. I have never seen those used inside rack mounted equipment. 3.If the power supply is UL Listed, then temperature measurements are not required. However, most power supplies are categorized as Recognized and are therefore incomplete in construction - that is, they cannot pass the safety requirements for a stand alone power supply. Temperature measurements will be required. 4.Stability is performed in a worst case situation, but reason is also taken into account. Most likely, you will determine that it is possible and reasonable to assume that more than one assembly can be extending at the same time. 5.UL requires that all internal equipment be UL Listed or Recognized. --- From: pe...@itl.co.il [SMTP:pe...@itl.co.il] Sent: Tuesday, March 09, 1999 11:26 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: Rack System Safety (UL1950/EN 60950) Questions Dear All, I would like to know some of your professional advice on some issues reagrding rack systems to be evaluated to UL1950/EN 60 950. 1. For the North America, does a NEMA 125 V, 20 A plug meet the pluggable B definition? 2. What are some plug configurations which will meet the pluggable B equipment requirements for North America and Europe? 3. Does anyone have experience with UL and/or CSA and/or TUV when testing a unit employing a Recognized/Certified/Approved computer type totally enclosed power supply? I am interested to know if temperatures should be monitored within such a power supply. So far, I have been asked to thermocouple various points within the power supply and as you all know, it could get very crowded in there. I am interested to know if someone out there knows if such a waiver exists for totally enclosed Approved power supplies. 4. When conducting stability tests for rack systems, should all the serviceable card cages be extended out or is it enough to do it one at a time. 5. For a CSA NRTLC unit employed in the rack system, does anyone know if the CSA NRTLC Mark is automatically accepted by UL or does UL require that the unit must be re-investigated and placed under their Follow-Up Program? 6. Has the US Robotics Listed Sporster card modem been evaluated to UL1950 Third Edition? 7. Can I List/Certify a rack system to UL1950 Third Edition if the units within it have been Listed/Certified to UL1950 First and/or Second Editions? I do not think so, but am interested to hear your opinions. 8. How is a CB test report done for a rack system which consists of previously Listed/Certified/Approved units? Does the CB scheme Recognize the Approvals of the various test agencies (UL/CSA/TUV)? Thanks in advance. PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send
Re: Rack System Safety (UL1950/EN 60950) Questions
Hello Peter: 1. For the North America, does a NEMA 125 V, 20 A plug meet the pluggable B definition? No. The objective of the Pluggable Type B connection is that of a reliable, non-defeatable earth connection. The NEMA 20 A plug uses the same earthing connection as the NEMA 15 A plug. The 15 A plug is notorious for having the earthing connection destroyed or removed in use. 2. What are some plug configurations which will meet the pluggable B equipment requirements for North America and Europe? I'm afraid I can't answer this question. I suggest you ask UL or CSA. 3. Does anyone have experience with UL and/or CSA and/or TUV when testing a unit employing a Recognized/Certified/Approved computer type totally enclosed power supply? I am interested to know if temperatures should be monitored within such a power supply. So far, I have been asked to thermocouple various points within the power supply and as you all know, it could get very crowded in there. I am interested to know if someone out there knows if such a waiver exists for totally enclosed Approved power supplies. Any component, including component power supplies, must be tested for temperature rise in the end-product configuration. It is not necessary to measure all of the same points as was done for the power supply safety qualification. I choose a sub-set of those, especially the highest temperatures. If the highest temperatures are okay in the end-product, then it is a good assumption that the lower temperatures are also okay. I would expect that you would only need to test 20% of the total test points. 4. When conducting stability tests for rack systems, should all the serviceable card cages be extended out or is it enough to do it one at a time. Testing is almost always the worst-case condition, regardless whether such condition is not expected in normal service. Doors, drawers, etc., which may be moved for servicing by the operator or by service personnel are placed in their most infavourable position, consistent with the manufacturer's instructions. 5. For a CSA NRTLC unit employed in the rack system, does anyone know if the CSA NRTLC Mark is automatically accepted by UL or does UL require that the unit must be re-investigated and placed under their Follow-Up Program? The CSA NRTL mark means the unit is acceptable for use in any USA workplace. The unit need not be also certified by UL. If CSA certifies the unit to the bi-national standard, then the certification is accepted by UL if you should submit the unit to UL as part of another equipment. Otherwise, it does not make much sense to also submit the unit to UL. Both CSA and UL and all other NRTLs have follow-up programs. This is a NRTL requirement. 6. Has the US Robotics Listed Sporster card modem been evaluated to UL1950 Third Edition? If so, such certification would be marked on the unit or on the packaging accompanying the unit. In addition, it would appear in the UL Listed Products book. 7. Can I List/Certify a rack system to UL1950 Third Edition if the units within it have been Listed/Certified to UL1950 First and/or Second Editions? I do not think so, but am interested to hear your opinions. No. All certifications of components and sub-systems must be to the same or newer edition of the standard as for the entire equipment. (In most cases, certification to newer editions also means compliance to former editions.) By the way, the differences between editions rarely mean the hardware does not comply with newer requirements. Re-evaluating the hardware to the newer editions rarely results in a need to change the hardware. Its an exercise which costs the submittor money, and benefits the certifier, but has no effect on the safety of the equipment, and has no benefit to the customer. I have several products certified to IEC 60950 Amd 1, 2, and 3. We're adding some new models to these families. All new models must now be evaluated to Amds 1, 2, 3, and 4. No hardware changes, but I must go through a complete new evaluation because Amd 4 is now in effect. Since safety is realized in the hardware, and since there is no hardware change, what is the value of Amd 4? 8. How is a CB test report done for a rack system which consists of previously Listed/Certified/Approved units? Does the CB scheme Recognize the Approvals of the various test agencies (UL/CSA/TUV)? A CB for a rack system must include CBs for each of the individual parts of the system. Or, each individual part must be evaluated in accordance with the standard. The NCB can use the listing/certification/ approval reports from other NCBs to reduce the amount of evaluation of those parts. But, the CB Report it issues must cover everything in the rack, either directly included in the CB Report or included as attachment CB Reports. Best regards, Rich
RE: Rack System Safety (UL1950/EN 60950) Questions
Peter,
Responses are below each question. (NOTE: The answers to these questions are
easily found in the UL 1950 3rd ed. standard).
-Original Message-
From: pe...@itl.co.il [mailto:pe...@itl.co.il]
Sent: Tuesday, March 09, 1999 11:26 AM
To: emc-p...@majordomo.ieee.org; t...@world.std.com
Subject: Rack System Safety (UL1950/EN 60950) Questions
Dear All,
I would like to know some of your professional advice on some
issues reagrding rack systems to be evaluated to UL1950/EN 60
950.
1. For the North America, does a NEMA 125 V, 20 A plug meet the
pluggable B definition?
Answer: As per UL1950 3rd Ed/CAN CSA C22.2 No.950 the answer is maybe.
If you are just talking a NEMA 5-20P then it is pluggable equipment A.
That is - non-industrial. If you use a NEMA L5-20P ('L' for locking or more
commonly refered to as 'Twist-Lock') then the answer is Yes. Pluggable
equipment Type B
requires an 'industrial type plug or appliance coupler.
2. What are some plug configurations which will meet the
pluggable B equipment requirements for North America and
Europe?
Answer: Quote from UL1950 Equipment iwhich is intended for connection to
the building power supply wiring via an industrial plug and socket-outlet or
an appliance coupler, or both, complying with IEC 309 or with national
standards for similar applications.
3. Does anyone have experience with UL and/or CSA and/or TUV
when testing a unit employing a Recognized/Certified/Approved
computer type totally enclosed power supply? I am interested to
know if temperatures should be monitored within such a power
supply. So far, I have been asked to thermocouple various points
within the power supply and as you all know, it could get very
crowded in there. I am interested to know if someone out there
knows if such a waiver exists for totally enclosed Approved power
supplies.
Answer: If said unit is located WITHIN YOUR enclosed product, you still need
to take temperature measurements. This is because since it is enclosed in
your product, you could increase the ambient temperature of the power
supply. Your product will be tested with all openings closed to determine if
the internal temperatures of the pwoer supply exceed that allowed
temperature rises. You are affecting the power supply's environment.
The power supply was originally tested in free air, now you are enclosing it
in your unit.
4. When conducting stability tests for rack systems, should all the
serviceable card cages be extended out or is it enough to do it one
at a time.
Answer: All the drawers could be extended out. They check the unit in its
most unfavorable condition.
5. For a CSA NRTLC unit employed in the rack system, does
anyone know if the CSA NRTLC Mark is automatically accepted by
UL or does UL require that the unit must be re-investigated and
placed under their Follow-Up Program?
Answer: The unit will not typically have to be re-investigated. If there is
cause for concern, they may require a temperature evaluation.
6. Has the US Robotics Listed Sporster card modem been
evaluated to UL1950 Third Edition?
Answer: Call US Robotics.
7. Can I List/Certify a rack system to UL1950 Third Edition if the
units within it have been Listed/Certified to UL1950 First and/or
Second Editions? I do not think so, but am interested to hear your
opinions.
Answer: I believe you can do this. After April 1, 2000 products that were
previously evaluated by UL to the requirements in other existing standards
(like 1st/second ed.) may continue to be approved until April 1, 2005
without further investigation, provided no significant changes or revisions
are made to such products.
8. How is a CB test report done for a rack system which consists
of previously Listed/Certified/Approved units? Does the CB scheme
Recognize the Approvals of the various test agencies
(UL/CSA/TUV)?
Answer: I can't answer this one. Anyone else??
John A. Juhasz
Product Qualification
Compliance Engr.
Fiber Options, Inc.
80 Orville Dr. Suite 102
Bohemia, NY 11716 USA
Tel: 516-567-8320 ext. 24
Fax: 516-567-8322
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RE: Rack System Safety (UL1950/EN 60950) Questions
1. Peter, equipment with the standard NEMA plug is considered to be Class A.. 2. Equipment using the heavy duty Industrial plugs complying with IEC are considered to be Class B. I have never seen those used inside rack mounted equipment. 3. If the power supply is UL Listed, then temperature measurements are not required. However, most power supplies are categorized as Recognized and are therefore incomplete in construction - that is, they cannot pass the safety requirements for a stand alone power supply. Temperature measurements will be required. 4. Stability is performed in a worst case situation, but reason is also taken into account. Most likely, you will determine that it is possible and reasonable to assume that more than one assembly can be extending at the same time. 5. UL requires that all internal equipment be UL Listed or Recognized. --- From: pe...@itl.co.il [SMTP:pe...@itl.co.il] Sent: Tuesday, March 09, 1999 11:26 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: Rack System Safety (UL1950/EN 60950) Questions Dear All, I would like to know some of your professional advice on some issues reagrding rack systems to be evaluated to UL1950/EN 60 950. 1. For the North America, does a NEMA 125 V, 20 A plug meet the pluggable B definition? 2. What are some plug configurations which will meet the pluggable B equipment requirements for North America and Europe? 3. Does anyone have experience with UL and/or CSA and/or TUV when testing a unit employing a Recognized/Certified/Approved computer type totally enclosed power supply? I am interested to know if temperatures should be monitored within such a power supply. So far, I have been asked to thermocouple various points within the power supply and as you all know, it could get very crowded in there. I am interested to know if someone out there knows if such a waiver exists for totally enclosed Approved power supplies. 4. When conducting stability tests for rack systems, should all the serviceable card cages be extended out or is it enough to do it one at a time. 5. For a CSA NRTLC unit employed in the rack system, does anyone know if the CSA NRTLC Mark is automatically accepted by UL or does UL require that the unit must be re-investigated and placed under their Follow-Up Program? 6. Has the US Robotics Listed Sporster card modem been evaluated to UL1950 Third Edition? 7. Can I List/Certify a rack system to UL1950 Third Edition if the units within it have been Listed/Certified to UL1950 First and/or Second Editions? I do not think so, but am interested to hear your opinions. 8. How is a CB test report done for a rack system which consists of previously Listed/Certified/Approved units? Does the CB scheme Recognize the Approvals of the various test agencies (UL/CSA/TUV)? Thanks in advance. PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
