RE: 94V-0 question
This is a multi-part message in MIME format. I might add that almost any plastic or fiber will pass 94V-0 in application if adhered to the metal enclosure. The heat sinking makes it almost impossible to burn. Bob Johnson ITE Safety From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of drcuthb...@micron.com Sent: Tuesday, August 12, 2003 1:55 PM To: emc-p...@majordomo.ieee.org Subject: 94V-0 question I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology Title: RE: 94V-0 question I might add that almost any plastic or fiber will pass 94V-0 in application if adhered to the metal enclosure. The heat sinking makes it almost impossible to burn. Bob Johnson ITE Safety -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of drcuthb...@micron.com Sent: Tuesday, August 12, 2003 1:55 PM To: emc-p...@majordomo.ieee.org Subject: 94V-0 question I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology attachment: Robert_Johnson.vcf
Re: 94V-0 question
Hi Dave: I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? With respect to IEC 60950... A plastic material used as an electrical insulator (creepage) has no flame-rating requirement. Rather, the material must be a suitable insulating material. Most plastics are suitable insulating materials. Check the UL electrical ratings for your candidate materials. If you are seeking UL certification or equivalent, then the material must be a UL-recognized plastic. If the material is within a fire enclosure, then the material must be V-2 or better. If it is not within a fire enclosure, then there is no flame rating requirement. If you are placing the material between the PCB and the metal enclosure, then I suspect you really mean clearance, not creepage. A creepage is a distance along the surface of an insulator. If the PCB abuts the metal enclosure, then it would indeed be a creepage (as well as a clearance). If the PCB does not abut the metal enclosure, then it is a clearance. This is a very important distinction. If the clearance does not meet the necessary distance, and if the metal enclosure is grounded, then the sheet insulator comprises Basic Insulation (and there is no thickness requirement). If the metal enclosure is not grounded, then the sheet insulator comprises Reinforced Insulation, in which case the material thickness must be 0.4 mm or more. Good luck, and best regards, Rich 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 94V-0 question
This is a multi-part message in MIME format. Dave, Some interesting comments and discussion so far. Let me comment that I often use insulation in chassis because of the creepage/clearance for the same issue you describe. Normally UL94V-2 is sufficient since the insulation is not in direct contact with hazardous currents and is not subject to resistive heating from current. Normally, I will use die-cut adhesive-backed Mylar or Nomex and this is applied by the sheet metal vendor as a value added operation. My choice of material thickness for insulation value is guided by a Technical Information Letter (TIL) from CSA. I use this information on products that are approved for use in Canada and the USA. The attached file is a small HTML page I adapted from that TIL a couple of years ago. I find it helpful. Regards, -doug Douglas E. Powell Corporate Compliance Dept. Advanced Energy Industries, Inc. Fort Collins, CO 80535 USA ___ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. Title: RE: 94V-0 question Dave, Some interesting comments and discussion so far. Let me comment that I often use insulation in chassis because of the creepage/clearance for the same issue you describe. Normally UL94V-2 is sufficient since the insulation is not in direct contact with hazardous currents and is not subject to resistive heating from current. Normally, I will use die-cut adhesive-backed Mylar or Nomex and this is applied by the sheet metal vendor as a value added operation. My choice of material thickness for insulation value is guided by a Technical Information Letter (TIL) from CSA. I use this information on products that are approved for use in Canada and the USA. The attached file is a small HTML page I adapted from that TIL a couple of years ago. I find it helpful. Regards, -doug Douglas E. Powell Corporate Compliance Dept. Advanced Energy Industries, Inc. Fort Collins, CO 80535 USA ___ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. attachment: CSA_TIL_I-3.zip
94V-0 question
Thanks to all for your sage comments! We will go with 20 mil Nomex. Dave Cuthbert Micron Technology 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 94V-0 question
Bryan - I know this is nit picking, but Nomex is a brand of aramid paper (a nonwoven polyester) and is not vulcanized fiber. I agree that it's an excellent insulating material, especially for high temperature applications, though pricier than other materials equally suited to Dave's particular application. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA peter.tar...@sanmina-sci.com From: Cole, Bryan [LBRT/CCC] Sent: Tuesday, August 12, 2003 1:11 PM This scenaro comes up often in our designs. We typically use 0.010 or 0.020 inch thick Nomex (vulcanized fiber) instead of plastic. The Nomex is UL recognized, 94V-0, very low cost and can be bought in sheets or punched to the exact size. Thanks, Bryan. 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 94V-0 question
1. You have already received many good material suggestions from by others but do you really need 94V-0? I believe that most standards will allow 94V-2 for this purpose (assuming it provides the necessary creepage clearance distances and passes the dielectric strength test). 2. If the enclosure is grounded, the insulation will serve as basic insulation = creepage clearance distance + hipot test. If the enclosure isn't grounded, the insulation will serve as reinforced insulation = be careful, some safety standards have a minimum thickness requirement for reinforced insulation if only one layer of the material is used (other standards indicate that whatever thickness passes the hipot test is acceptable). 3. I suggest that you consider a method of mechanical securement so you don't have to worry about the reliability/certification of an adhesive. Punching holes in the insulation that fit over existing standoffs is one option. 4. Be careful if there is any pressure between the board and enclosure = this could create reliability questions if a sharp solder pad could put a hole through the insulation. Regards, Bill Bisenius E.D. D. bi...@productsafet.com -Original Message- From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: Tuesday, August 12, 2003 1:55 PM To: emc-p...@majordomo.ieee.org Subject:94V-0 question I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 94V-0 question
I read in !emc-pstc that drcuthb...@micron.com wrote (in E6F64B42266D6 54b80a0f7f4b98212a5cf1...@ntxboimbx03.micron.com) about '94V-0 question' on Tue, 12 Aug 2003: I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. The dimensions matter a lot. Please give more detail. If the sheet is bonded to the metal, its flammability rating will probably be greatly improved. Polycarbonate is an unusual material for this sort of application, I think. You might consider polyethylene terephthalate. -- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 94V-0 question
This scenaro comes up often in our designs. We typically use 0.010 or 0.020 inch thick Nomex (vulcanized fiber) instead of plastic. The Nomex is UL recognized, 94V-0, very low cost and can be bought in sheets or punched to the exact size. Thanks, Bryan. From: drcuthb...@micron.com To: emc-p...@majordomo.ieee.org Sent: 8/12/03 1:55 PM Subject: 94V-0 question I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 94V-0 question
Hello Dave, Nomex paper (sheet stock) will do the trick, I believe. Best regards, Art Michael, Editor, IPSN -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- |http://www.safetylink.com | || | The Safety Link is the most comprehensive collection | |of product safety and standards links on the WEB| || | Int'l Product Safety News | |(It's our 15th Anniversary 1988-2003 | | P.O.Box 1561 - WWW | |Middletown CT 06457-8061 U.S.A. | | Phone: (860) 344-1651 Fax: (860) 346-9066 | | email: i...@safetylink.com| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- On Tue, 12 Aug 2003 drcuthb...@micron.com wrote: I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 94V-0 question
Dave - You don't identify the end-product safety standard, but here goes. Not all polymeric materials are created equal, often not even in the same generic family. Any number of key material parameters might change with the formulation of the resin. To be certain you have a material that meets your needs, you can use UL's on-line Plastics IQ database. It's searchable by parameters, including flammability, generic type, thickness, and other common properties. V-0 is probably a good property to have; it's usually enough for a barrier. However, if the end-product standard(s) include a UL standard that relies on UL746C (Standard for Polymeric Materials; Use in Electrical Equipment Evaluations) as a reference standard, you may have a number of other material parameters to match up, on top of flammability classification. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA peter.tar...@sanmina-sci.com From: drcuthb...@micron.com Sent: Tuesday, August 12, 2003 10:55 AM I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 94V-0 question
DuPont Nomex, GE Lexan, and GE Valox From: drcuthb...@micron.com Reply-To: drcuthb...@micron.com To: emc-p...@majordomo.ieee.org Subject: 94V-0 question Date: Tue, 12 Aug 2003 11:55:25 -0600 I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc _ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 94V-0 question
Not all polycarbonates are V-0. I tend to use Valox: easy to both machine and hand-cut, good dielectric (have tested single 0.003in sheet to 5kV), most thicknesses are V-0 rated, and has decent (non) water absorption properties. I also like to have the mechanical designers put a sheet between chassis and PCB so that any bad SFC will not result in failure of subsequent hi-pot. luck, Brian -Original Message- From: drcuthb...@micron.com [ mailto:drcuthb...@micron.com] Sent: Tuesday, August 12, 2003 10:55 AM To: emc-p...@majordomo.ieee.org Subject: 94V-0 question I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 94V-0 question
Kapton comes to mind. - Robert - On Tue, 12 Aug 2003 11:55:25 -0600 drcuthb...@micron.com wrote: I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
94V-0 question
I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
